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2020-03-30bpf: Verifier, refine 32bit bound in do_refine_retval_rangeJohn Fastabend1-0/+1
Further refine return values range in do_refine_retval_range by noting these are int return types (We will assume here that int is a 32-bit type). Two reasons to pull this out of original patch. First it makes the original fix impossible to backport. And second I've not seen this as being problematic in practice unlike the other case. Fixes: 849fa50662fbc ("bpf/verifier: refine retval R0 state for bpf_get_stack helper") Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/158560421952.10843.12496354931526965046.stgit@john-Precision-5820-Tower
2020-03-30bpf: Verifier, do explicit ALU32 bounds trackingJohn Fastabend2-281/+852
It is not possible for the current verifier to track ALU32 and JMP ops correctly. This can result in the verifier aborting with errors even though the program should be verifiable. BPF codes that hit this can work around it by changin int variables to 64-bit types, marking variables volatile, etc. But this is all very ugly so it would be better to avoid these tricks. But, the main reason to address this now is do_refine_retval_range() was assuming return values could not be negative. Once we fixed this code that was previously working will no longer work. See do_refine_retval_range() patch for details. And we don't want to suddenly cause programs that used to work to fail. The simplest example code snippet that illustrates the problem is likely this, 53: w8 = w0 // r8 <- [0, S32_MAX], // w8 <- [-S32_MIN, X] 54: w8 <s 0 // r8 <- [0, U32_MAX] // w8 <- [0, X] The expected 64-bit and 32-bit bounds after each line are shown on the right. The current issue is without the w* bounds we are forced to use the worst case bound of [0, U32_MAX]. To resolve this type of case, jmp32 creating divergent 32-bit bounds from 64-bit bounds, we add explicit 32-bit register bounds s32_{min|max}_value and u32_{min|max}_value. Then from branch_taken logic creating new bounds we can track 32-bit bounds explicitly. The next case we observed is ALU ops after the jmp32, 53: w8 = w0 // r8 <- [0, S32_MAX], // w8 <- [-S32_MIN, X] 54: w8 <s 0 // r8 <- [0, U32_MAX] // w8 <- [0, X] 55: w8 += 1 // r8 <- [0, U32_MAX+1] // w8 <- [0, X+1] In order to keep the bounds accurate at this point we also need to track ALU32 ops. To do this we add explicit ALU32 logic for each of the ALU ops, mov, add, sub, etc. Finally there is a question of how and when to merge bounds. The cases enumerate here, 1. MOV ALU32 - zext 32-bit -> 64-bit 2. MOV ALU64 - copy 64-bit -> 32-bit 3. op ALU32 - zext 32-bit -> 64-bit 4. op ALU64 - n/a 5. jmp ALU32 - 64-bit: var32_off | upper_32_bits(var64_off) 6. jmp ALU64 - 32-bit: (>> (<< var64_off)) Details for each case, For "MOV ALU32" BPF arch zero extends so we simply copy the bounds from 32-bit into 64-bit ensuring we truncate var_off and 64-bit bounds correctly. See zext_32_to_64. For "MOV ALU64" copy all bounds including 32-bit into new register. If the src register had 32-bit bounds the dst register will as well. For "op ALU32" zero extend 32-bit into 64-bit the same as move, see zext_32_to_64. For "op ALU64" calculate both 32-bit and 64-bit bounds no merging is done here. Except we have a special case. When RSH or ARSH is done we can't simply ignore shifting bits from 64-bit reg into the 32-bit subreg. So currently just push bounds from 64-bit into 32-bit. This will be correct in the sense that they will represent a valid state of the register. However we could lose some accuracy if an ARSH is following a jmp32 operation. We can handle this special case in a follow up series. For "jmp ALU32" mark 64-bit reg unknown and recalculate 64-bit bounds from tnum by setting var_off to ((<<(>>var_off)) | var32_off). We special case if 64-bit bounds has zero'd upper 32bits at which point we can simply copy 32-bit bounds into 64-bit register. This catches a common compiler trick where upper 32-bits are zeroed and then 32-bit ops are used followed by a 64-bit compare or 64-bit op on a pointer. See __reg_combine_64_into_32(). For "jmp ALU64" cast the bounds of the 64bit to their 32-bit counterpart. For example s32_min_value = (s32)reg->smin_value. For tnum use only the lower 32bits via, (>>(<<var_off)). See __reg_combine_64_into_32(). Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/158560419880.10843.11448220440809118343.stgit@john-Precision-5820-Tower
2020-03-30bpf: Verifier, do_refine_retval_range may clamp umin to 0 incorrectlyJohn Fastabend1-8/+11
do_refine_retval_range() is called to refine return values from specified helpers, probe_read_str and get_stack at the moment, the reasoning is because both have a max value as part of their input arguments and because the helper ensure the return value will not be larger than this we can set smax values of the return register, r0. However, the return value is a signed integer so setting umax is incorrect It leads to further confusion when the do_refine_retval_range() then calls, __reg_deduce_bounds() which will see a umax value as meaning the value is unsigned and then assuming it is unsigned set the smin = umin which in this case results in 'smin = 0' and an 'smax = X' where X is the input argument from the helper call. Here are the comments from _reg_deduce_bounds() on why this would be safe to do. /* Learn sign from unsigned bounds. Signed bounds cross the sign * boundary, so we must be careful. */ if ((s64)reg->umax_value >= 0) { /* Positive. We can't learn anything from the smin, but smax * is positive, hence safe. */ reg->smin_value = reg->umin_value; reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, reg->umax_value); But now we incorrectly have a return value with type int with the signed bounds (0,X). Suppose the return value is negative, which is possible the we have the verifier and reality out of sync. Among other things this may result in any error handling code being falsely detected as dead-code and removed. For instance the example below shows using bpf_probe_read_str() causes the error path to be identified as dead code and removed. >From the 'llvm-object -S' dump, r2 = 100 call 45 if r0 s< 0 goto +4 r4 = *(u32 *)(r7 + 0) But from dump xlate (b7) r2 = 100 (85) call bpf_probe_read_compat_str#-96768 (61) r4 = *(u32 *)(r7 +0) <-- dropped if goto Due to verifier state after call being R0=inv(id=0,umax_value=100,var_off=(0x0; 0x7f)) To fix omit setting the umax value because its not safe. The only actual bounds we know is the smax. This results in the correct bounds (SMIN, X) where X is the max length from the helper. After this the new verifier state looks like the following after call 45. R0=inv(id=0,smax_value=100) Then xlated version no longer removed dead code giving the expected result, (b7) r2 = 100 (85) call bpf_probe_read_compat_str#-96768 (c5) if r0 s< 0x0 goto pc+4 (61) r4 = *(u32 *)(r7 +0) Note, bpf_probe_read_* calls are root only so we wont hit this case with non-root bpf users. v3: comment had some documentation about meta set to null case which is not relevant here and confusing to include in the comment. v2 note: In original version we set msize_smax_value from check_func_arg() and propagated this into smax of retval. The logic was smax is the bound on the retval we set and because the type in the helper is ARG_CONST_SIZE we know that the reg is a positive tnum_const() so umax=smax. Alexei pointed out though this is a bit odd to read because the register in check_func_arg() has a C type of u32 and the umax bound would be the normally relavent bound here. Pulling in extra knowledge about future checks makes reading the code a bit tricky. Further having a signed meta data that can only ever be positive is also a bit odd. So dropped the msize_smax_value metadata and made it a u64 msize_max_value to indicate its unsigned. And additionally save bound from umax value in check_arg_funcs which is the same as smax due to as noted above tnumx_cont and negative check but reads better. By my analysis nothing functionally changes in v2 but it does get easier to read so that is win. Fixes: 849fa50662fbc ("bpf/verifier: refine retval R0 state for bpf_get_stack helper") Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/158560417900.10843.14351995140624628941.stgit@john-Precision-5820-Tower
2020-03-30bpf: btf: Fix arg verification in btf_ctx_access()KP Singh1-7/+17
The bounds checking for the arguments accessed in the BPF program breaks when the expected_attach_type is not BPF_TRACE_FEXIT, BPF_LSM_MAC or BPF_MODIFY_RETURN resulting in no check being done for the default case (the programs which do not receive the return value of the attached function in its arguments) when the index of the argument being accessed is equal to the number of arguments (nr_args). This was a result of a misplaced "else if" block introduced by the Commit 6ba43b761c41 ("bpf: Attachment verification for BPF_MODIFY_RETURN") Fixes: 6ba43b761c41 ("bpf: Attachment verification for BPF_MODIFY_RETURN") Reported-by: Jann Horn <[email protected]> Signed-off-by: KP Singh <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: Simplify reg_set_min_max_inv handlingJann Horn1-86/+22
reg_set_min_max_inv() contains exactly the same logic as reg_set_min_max(), just flipped around. While this makes sense in a cBPF verifier (where ALU operations are not symmetric), it does not make sense for eBPF. Replace reg_set_min_max_inv() with a helper that flips the opcode around, then lets reg_set_min_max() do the complicated work. Signed-off-by: Jann Horn <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: Fix tnum constraints for 32-bit comparisonsJann Horn1-36/+72
The BPF verifier tried to track values based on 32-bit comparisons by (ab)using the tnum state via 581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions"). The idea is that after a check like this: if ((u32)r0 > 3) exit We can't meaningfully constrain the arithmetic-range-based tracking, but we can update the tnum state to (value=0,mask=0xffff'ffff'0000'0003). However, the implementation from 581738a681b6 didn't compute the tnum constraint based on the fixed operand, but instead derives it from the arithmetic-range-based tracking. This means that after the following sequence of operations: if (r0 >= 0x1'0000'0001) exit if ((u32)r0 > 7) exit The verifier assumed that the lower half of r0 is in the range (0, 0) and apply the tnum constraint (value=0,mask=0xffff'ffff'0000'0000) thus causing the overall tnum to be (value=0,mask=0x1'0000'0000), which was incorrect. Provide a fixed implementation. Fixes: 581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions") Signed-off-by: Jann Horn <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: Undo incorrect __reg_bound_offset32 handlingDaniel Borkmann1-19/+0
Anatoly has been fuzzing with kBdysch harness and reported a hang in one of the outcomes: 0: (b7) r0 = 808464432 1: (7f) r0 >>= r0 2: (14) w0 -= 808464432 3: (07) r0 += 808464432 4: (b7) r1 = 808464432 5: (de) if w1 s<= w0 goto pc+0 R0_w=invP(id=0,umin_value=808464432,umax_value=5103431727,var_off=(0x30303020;0x10000001f)) R1_w=invP808464432 R10=fp0 6: (07) r0 += -2144337872 7: (14) w0 -= -1607454672 8: (25) if r0 > 0x30303030 goto pc+0 R0_w=invP(id=0,umin_value=271581184,umax_value=271581311,var_off=(0x10300000;0x7f)) R1_w=invP808464432 R10=fp0 9: (76) if w0 s>= 0x303030 goto pc+2 12: (95) exit from 8 to 9: safe from 5 to 6: R0_w=invP(id=0,umin_value=808464432,umax_value=5103431727,var_off=(0x30303020;0x10000001f)) R1_w=invP808464432 R10=fp0 6: (07) r0 += -2144337872 7: (14) w0 -= -1607454672 8: (25) if r0 > 0x30303030 goto pc+0 R0_w=invP(id=0,umin_value=271581184,umax_value=271581311,var_off=(0x10300000;0x7f)) R1_w=invP808464432 R10=fp0 9: safe from 8 to 9: safe verification time 589 usec stack depth 0 processed 17 insns (limit 1000000) [...] The underlying program was xlated as follows: # bpftool p d x i 9 0: (b7) r0 = 808464432 1: (7f) r0 >>= r0 2: (14) w0 -= 808464432 3: (07) r0 += 808464432 4: (b7) r1 = 808464432 5: (de) if w1 s<= w0 goto pc+0 6: (07) r0 += -2144337872 7: (14) w0 -= -1607454672 8: (25) if r0 > 0x30303030 goto pc+0 9: (76) if w0 s>= 0x303030 goto pc+2 10: (05) goto pc-1 11: (05) goto pc-1 12: (95) exit The verifier rewrote original instructions it recognized as dead code with 'goto pc-1', but reality differs from verifier simulation in that we're actually able to trigger a hang due to hitting the 'goto pc-1' instructions. Taking different examples to make the issue more obvious: in this example we're probing bounds on a completely unknown scalar variable in r1: [...] 5: R0_w=inv1 R1_w=inv(id=0) R10=fp0 5: (18) r2 = 0x4000000000 7: R0_w=inv1 R1_w=inv(id=0) R2_w=inv274877906944 R10=fp0 7: (18) r3 = 0x2000000000 9: R0_w=inv1 R1_w=inv(id=0) R2_w=inv274877906944 R3_w=inv137438953472 R10=fp0 9: (18) r4 = 0x400 11: R0_w=inv1 R1_w=inv(id=0) R2_w=inv274877906944 R3_w=inv137438953472 R4_w=inv1024 R10=fp0 11: (18) r5 = 0x200 13: R0_w=inv1 R1_w=inv(id=0) R2_w=inv274877906944 R3_w=inv137438953472 R4_w=inv1024 R5_w=inv512 R10=fp0 13: (2d) if r1 > r2 goto pc+4 R0_w=inv1 R1_w=inv(id=0,umax_value=274877906944,var_off=(0x0; 0x7fffffffff)) R2_w=inv274877906944 R3_w=inv137438953472 R4_w=inv1024 R5_w=inv512 R10=fp0 14: R0_w=inv1 R1_w=inv(id=0,umax_value=274877906944,var_off=(0x0; 0x7fffffffff)) R2_w=inv274877906944 R3_w=inv137438953472 R4_w=inv1024 R5_w=inv512 R10=fp0 14: (ad) if r1 < r3 goto pc+3 R0_w=inv1 R1_w=inv(id=0,umin_value=137438953472,umax_value=274877906944,var_off=(0x0; 0x7fffffffff)) R2_w=inv274877906944 R3_w=inv137438953472 R4_w=inv1024 R5_w=inv512 R10=fp0 15: R0=inv1 R1=inv(id=0,umin_value=137438953472,umax_value=274877906944,var_off=(0x0; 0x7fffffffff)) R2=inv274877906944 R3=inv137438953472 R4=inv1024 R5=inv512 R10=fp0 15: (2e) if w1 > w4 goto pc+2 R0=inv1 R1=inv(id=0,umin_value=137438953472,umax_value=274877906944,var_off=(0x0; 0x7f00000000)) R2=inv274877906944 R3=inv137438953472 R4=inv1024 R5=inv512 R10=fp0 16: R0=inv1 R1=inv(id=0,umin_value=137438953472,umax_value=274877906944,var_off=(0x0; 0x7f00000000)) R2=inv274877906944 R3=inv137438953472 R4=inv1024 R5=inv512 R10=fp0 16: (ae) if w1 < w5 goto pc+1 R0=inv1 R1=inv(id=0,umin_value=137438953472,umax_value=274877906944,var_off=(0x0; 0x7f00000000)) R2=inv274877906944 R3=inv137438953472 R4=inv1024 R5=inv512 R10=fp0 [...] We're first probing lower/upper bounds via jmp64, later we do a similar check via jmp32 and examine the resulting var_off there. After fall-through in insn 14, we get the following bounded r1 with 0x7fffffffff unknown marked bits in the variable section. Thus, after knowing r1 <= 0x4000000000 and r1 >= 0x2000000000: max: 0b100000000000000000000000000000000000000 / 0x4000000000 var: 0b111111111111111111111111111111111111111 / 0x7fffffffff min: 0b010000000000000000000000000000000000000 / 0x2000000000 Now, in insn 15 and 16, we perform a similar probe with lower/upper bounds in jmp32. Thus, after knowing r1 <= 0x4000000000 and r1 >= 0x2000000000 and w1 <= 0x400 and w1 >= 0x200: max: 0b100000000000000000000000000000000000000 / 0x4000000000 var: 0b111111100000000000000000000000000000000 / 0x7f00000000 min: 0b010000000000000000000000000000000000000 / 0x2000000000 The lower/upper bounds haven't changed since they have high bits set in u64 space and the jmp32 tests can only refine bounds in the low bits. However, for the var part the expectation would have been 0x7f000007ff or something less precise up to 0x7fffffffff. A outcome of 0x7f00000000 is not correct since it would contradict the earlier probed bounds where we know that the result should have been in [0x200,0x400] in u32 space. Therefore, tests with such info will lead to wrong verifier assumptions later on like falsely predicting conditional jumps to be always taken, etc. The issue here is that __reg_bound_offset32()'s implementation from commit 581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions") makes an incorrect range assumption: static void __reg_bound_offset32(struct bpf_reg_state *reg) { u64 mask = 0xffffFFFF; struct tnum range = tnum_range(reg->umin_value & mask, reg->umax_value & mask); struct tnum lo32 = tnum_cast(reg->var_off, 4); struct tnum hi32 = tnum_lshift(tnum_rshift(reg->var_off, 32), 32); reg->var_off = tnum_or(hi32, tnum_intersect(lo32, range)); } In the above walk-through example, __reg_bound_offset32() as-is chose a range after masking with 0xffffffff of [0x0,0x0] since umin:0x2000000000 and umax:0x4000000000 and therefore the lo32 part was clamped to 0x0 as well. However, in the umin:0x2000000000 and umax:0x4000000000 range above we'd end up with an actual possible interval of [0x0,0xffffffff] for u32 space instead. In case of the original reproducer, the situation looked as follows at insn 5 for r0: [...] 5: R0_w=invP(id=0,umin_value=808464432,umax_value=5103431727,var_off=(0x0; 0x1ffffffff)) R1_w=invP808464432 R10=fp0 0x30303030 0x13030302f 5: (de) if w1 s<= w0 goto pc+0 R0_w=invP(id=0,umin_value=808464432,umax_value=5103431727,var_off=(0x30303020; 0x10000001f)) R1_w=invP808464432 R10=fp0 0x30303030 0x13030302f [...] After the fall-through, we similarly forced the var_off result into the wrong range [0x30303030,0x3030302f] suggesting later on that fixed bits must only be of 0x30303020 with 0x10000001f unknowns whereas such assumption can only be made when both bounds in hi32 range match. Originally, I was thinking to fix this by moving reg into a temp reg and use proper coerce_reg_to_size() helper on the temp reg where we can then based on that define the range tnum for later intersection: static void __reg_bound_offset32(struct bpf_reg_state *reg) { struct bpf_reg_state tmp = *reg; struct tnum lo32, hi32, range; coerce_reg_to_size(&tmp, 4); range = tnum_range(tmp.umin_value, tmp.umax_value); lo32 = tnum_cast(reg->var_off, 4); hi32 = tnum_lshift(tnum_rshift(reg->var_off, 32), 32); reg->var_off = tnum_or(hi32, tnum_intersect(lo32, range)); } In the case of the concrete example, this gives us a more conservative unknown section. Thus, after knowing r1 <= 0x4000000000 and r1 >= 0x2000000000 and w1 <= 0x400 and w1 >= 0x200: max: 0b100000000000000000000000000000000000000 / 0x4000000000 var: 0b111111111111111111111111111111111111111 / 0x7fffffffff min: 0b010000000000000000000000000000000000000 / 0x2000000000 However, above new __reg_bound_offset32() has no effect on refining the knowledge of the register contents. Meaning, if the bounds in hi32 range mismatch we'll get the identity function given the range reg spans [0x0,0xffffffff] and we cast var_off into lo32 only to later on binary or it again with the hi32. Likewise, if the bounds in hi32 range match, then we mask both bounds with 0xffffffff, use the resulting umin/umax for the range to later intersect the lo32 with it. However, _prior_ called __reg_bound_offset() did already such intersection on the full reg and we therefore would only repeat the same operation on the lo32 part twice. Given this has no effect and the original commit had false assumptions, this patch reverts the code entirely which is also more straight forward for stable trees: apparently 581738a681b6 got auto-selected by Sasha's ML system and misclassified as a fix, so it got sucked into v5.4 where it should never have landed. A revert is low-risk also from a user PoV since it requires a recent kernel and llc to opt-into -mcpu=v3 BPF CPU to generate jmp32 instructions. A proper bounds refinement would need a significantly more complex approach which is currently being worked, but no stable material [0]. Hence revert is best option for stable. After the revert, the original reported program gets rejected as follows: 1: (7f) r0 >>= r0 2: (14) w0 -= 808464432 3: (07) r0 += 808464432 4: (b7) r1 = 808464432 5: (de) if w1 s<= w0 goto pc+0 R0_w=invP(id=0,umin_value=808464432,umax_value=5103431727,var_off=(0x0; 0x1ffffffff)) R1_w=invP808464432 R10=fp0 6: (07) r0 += -2144337872 7: (14) w0 -= -1607454672 8: (25) if r0 > 0x30303030 goto pc+0 R0_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x3fffffff)) R1_w=invP808464432 R10=fp0 9: (76) if w0 s>= 0x303030 goto pc+2 R0=invP(id=0,umax_value=3158063,var_off=(0x0; 0x3fffff)) R1=invP808464432 R10=fp0 10: (30) r0 = *(u8 *)skb[808464432] BPF_LD_[ABS|IND] uses reserved fields processed 11 insns (limit 1000000) [...] [0] https://lore.kernel.org/bpf/158507130343.15666.8018068546764556975.stgit@john-Precision-5820-Tower/T/ Fixes: 581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions") Reported-by: Anatoly Trosinenko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: lsm: Implement attach, detach and executionKP Singh5-27/+105
JITed BPF programs are dynamically attached to the LSM hooks using BPF trampolines. The trampoline prologue generates code to handle conversion of the signature of the hook to the appropriate BPF context. The allocated trampoline programs are attached to the nop functions initialized as LSM hooks. BPF_PROG_TYPE_LSM programs must have a GPL compatible license and and need CAP_SYS_ADMIN (required for loading eBPF programs). Upon attachment: * A BPF fexit trampoline is used for LSM hooks with a void return type. * A BPF fmod_ret trampoline is used for LSM hooks which return an int. The attached programs can override the return value of the bpf LSM hook to indicate a MAC Policy decision. Signed-off-by: KP Singh <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Reviewed-by: Brendan Jackman <[email protected]> Reviewed-by: Florent Revest <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: James Morris <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: lsm: Provide attachment points for BPF LSM programsKP Singh1-0/+14
When CONFIG_BPF_LSM is enabled, nop functions, bpf_lsm_<hook_name>, are generated for each LSM hook. These functions are initialized as LSM hooks in a subsequent patch. Signed-off-by: KP Singh <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Reviewed-by: Brendan Jackman <[email protected]> Reviewed-by: Florent Revest <[email protected]> Reviewed-by: Kees Cook <[email protected]> Acked-by: Yonghong Song <[email protected]> Acked-by: James Morris <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-30bpf: Introduce BPF_PROG_TYPE_LSMKP Singh3-6/+24
Introduce types and configs for bpf programs that can be attached to LSM hooks. The programs can be enabled by the config option CONFIG_BPF_LSM. Signed-off-by: KP Singh <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Reviewed-by: Brendan Jackman <[email protected]> Reviewed-by: Florent Revest <[email protected]> Reviewed-by: Thomas Garnier <[email protected]> Acked-by: Yonghong Song <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: James Morris <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-27bpf: Enable bpf cgroup hooks to retrieve cgroup v2 and ancestor idDaniel Borkmann2-0/+19
Enable the bpf_get_current_cgroup_id() helper for connect(), sendmsg(), recvmsg() and bind-related hooks in order to retrieve the cgroup v2 context which can then be used as part of the key for BPF map lookups, for example. Given these hooks operate in process context 'current' is always valid and pointing to the app that is performing mentioned syscalls if it's subject to a v2 cgroup. Also with same motivation of commit 7723628101aa ("bpf: Introduce bpf_skb_ancestor_cgroup_id helper") enable retrieval of ancestor from current so the cgroup id can be used for policy lookups which can then forbid connect() / bind(), for example. Signed-off-by: Daniel Borkmann <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/d2a7ef42530ad299e3cbb245e6c12374b72145ef.1585323121.git.daniel@iogearbox.net
2020-03-27bpf: Add netns cookie and enable it for bpf cgroup hooksDaniel Borkmann1-6/+10
In Cilium we're mainly using BPF cgroup hooks today in order to implement kube-proxy free Kubernetes service translation for ClusterIP, NodePort (*), ExternalIP, and LoadBalancer as well as HostPort mapping [0] for all traffic between Cilium managed nodes. While this works in its current shape and avoids packet-level NAT for inter Cilium managed node traffic, there is one major limitation we're facing today, that is, lack of netns awareness. In Kubernetes, the concept of Pods (which hold one or multiple containers) has been built around network namespaces, so while we can use the global scope of attaching to root BPF cgroup hooks also to our advantage (e.g. for exposing NodePort ports on loopback addresses), we also have the need to differentiate between initial network namespaces and non-initial one. For example, ExternalIP services mandate that non-local service IPs are not to be translated from the host (initial) network namespace as one example. Right now, we have an ugly work-around in place where non-local service IPs for ExternalIP services are not xlated from connect() and friends BPF hooks but instead via less efficient packet-level NAT on the veth tc ingress hook for Pod traffic. On top of determining whether we're in initial or non-initial network namespace we also have a need for a socket-cookie like mechanism for network namespaces scope. Socket cookies have the nice property that they can be combined as part of the key structure e.g. for BPF LRU maps without having to worry that the cookie could be recycled. We are planning to use this for our sessionAffinity implementation for services. Therefore, add a new bpf_get_netns_cookie() helper which would resolve both use cases at once: bpf_get_netns_cookie(NULL) would provide the cookie for the initial network namespace while passing the context instead of NULL would provide the cookie from the application's network namespace. We're using a hole, so no size increase; the assignment happens only once. Therefore this allows for a comparison on initial namespace as well as regular cookie usage as we have today with socket cookies. We could later on enable this helper for other program types as well as we would see need. (*) Both externalTrafficPolicy={Local|Cluster} types [0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.c Signed-off-by: Daniel Borkmann <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/c47d2346982693a9cf9da0e12690453aded4c788.1585323121.git.daniel@iogearbox.net
2020-03-26bpf: Remove unused vairable 'bpf_xdp_link_lops'YueHaibing1-1/+0
kernel/bpf/syscall.c:2263:34: warning: 'bpf_xdp_link_lops' defined but not used [-Wunused-const-variable=] static const struct bpf_link_ops bpf_xdp_link_lops; ^~~~~~~~~~~~~~~~~ commit 70ed506c3bbc ("bpf: Introduce pinnable bpf_link abstraction") involded this unused variable, remove it. Reported-by: Hulk Robot <[email protected]> Signed-off-by: YueHaibing <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-26bpf: Factor out attach_type to prog_type mapping for attach/detachAndrii Nakryiko1-87/+66
Factor out logic mapping expected program attach type to program type and subsequent handling of program attach/detach. Also list out all supported cgroup BPF program types explicitly to prevent accidental bugs once more program types are added to a mapping. Do the same for prog_query API. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-26bpf: Factor out cgroup storages operationsAndrii Nakryiko1-46/+72
Refactor cgroup attach/detach code to abstract away common operations performed on all types of cgroup storages. This makes high-level logic more apparent, plus allows to reuse more code across multiple functions. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-25bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds()John Fastabend1-0/+1
Currently, for all op verification we call __red_deduce_bounds() and __red_bound_offset() but we only call __update_reg_bounds() in bitwise ops. However, we could benefit from calling __update_reg_bounds() in BPF_ADD, BPF_SUB, and BPF_MUL cases as well. For example, a register with state 'R1_w=invP0' when we subtract from it, w1 -= 2 Before coerce we will now have an smin_value=S64_MIN, smax_value=U64_MAX and unsigned bounds umin_value=0, umax_value=U64_MAX. These will then be clamped to S32_MIN, U32_MAX values by coerce in the case of alu32 op as done in above example. However tnum will be a constant because the ALU op is done on a constant. Without update_reg_bounds() we have a scenario where tnum is a const but our unsigned bounds do not reflect this. By calling update_reg_bounds after coerce to 32bit we further refine the umin_value to U64_MAX in the alu64 case or U32_MAX in the alu32 case above. Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/158507151689.15666.566796274289413203.stgit@john-Precision-5820-Tower
2020-03-25bpf: Verifer, refactor adjust_scalar_min_max_valsJohn Fastabend1-164/+239
Pull per op ALU logic into individual functions. We are about to add u32 versions of each of these by pull them out the code gets a bit more readable here and nicer in the next patch. Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/158507149518.15666.15672349629329072411.stgit@john-Precision-5820-Tower
2020-03-19bpf: Support llvm-objcopy for vmlinux BTFFangrui Song2-11/+9
Simplify gen_btf logic to make it work with llvm-objcopy. The existing 'file format' and 'architecture' parsing logic is brittle and does not work with llvm-objcopy/llvm-objdump. 'file format' output of llvm-objdump>=11 will match GNU objdump, but 'architecture' (bfdarch) may not. .BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag because it is part of vmlinux image used for introspection. C code can reference the section via linker script defined __start_BTF and __stop_BTF. This fixes a small problem that previous .BTF had the SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data). Additionally, `objcopy -I binary` synthesized symbols _binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not used elsewhere) are replaced with more commonplace __start_BTF and __stop_BTF. Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns "empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?" We use a dd command to change the e_type field in the ELF header from ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o. Accepting ET_EXEC as an input file is an extremely rare GNU ld feature that lld does not intend to support, because this is error-prone. The output section description .BTF in include/asm-generic/vmlinux.lds.h avoids potential subtle orphan section placement issues and suppresses --orphan-handling=warn warnings. Fixes: df786c9b9476 ("bpf: Force .BTF section start to zero when dumping from vmlinux") Fixes: cb0cc635c7a9 ("powerpc: Include .BTF section") Reported-by: Nathan Chancellor <[email protected]> Signed-off-by: Fangrui Song <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Tested-by: Stanislav Fomichev <[email protected]> Tested-by: Andrii Nakryiko <[email protected]> Reviewed-by: Stanislav Fomichev <[email protected]> Reviewed-by: Kees Cook <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Michael Ellerman <[email protected]> (powerpc) Link: https://github.com/ClangBuiltLinux/linux/issues/871 Link: https://lore.kernel.org/bpf/[email protected]
2020-03-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller12-219/+542
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-03-13 The following pull-request contains BPF updates for your *net-next* tree. We've added 86 non-merge commits during the last 12 day(s) which contain a total of 107 files changed, 5771 insertions(+), 1700 deletions(-). The main changes are: 1) Add modify_return attach type which allows to attach to a function via BPF trampoline and is run after the fentry and before the fexit programs and can pass a return code to the original caller, from KP Singh. 2) Generalize BPF's kallsyms handling and add BPF trampoline and dispatcher objects to be visible in /proc/kallsyms so they can be annotated in stack traces, from Jiri Olsa. 3) Extend BPF sockmap to allow for UDP next to existing TCP support in order in order to enable this for BPF based socket dispatch, from Lorenz Bauer. 4) Introduce a new bpftool 'prog profile' command which attaches to existing BPF programs via fentry and fexit hooks and reads out hardware counters during that period, from Song Liu. Example usage: bpftool prog profile id 337 duration 3 cycles instructions llc_misses 4228 run_cnt 3403698 cycles (84.08%) 3525294 instructions # 1.04 insn per cycle (84.05%) 13 llc_misses # 3.69 LLC misses per million isns (83.50%) 5) Batch of improvements to libbpf, bpftool and BPF selftests. Also addition of a new bpf_link abstraction to keep in particular BPF tracing programs attached even when the applicaion owning them exits, from Andrii Nakryiko. 6) New bpf_get_current_pid_tgid() helper for tracing to perform PID filtering and which returns the PID as seen by the init namespace, from Carlos Neira. 7) Refactor of RISC-V JIT code to move out common pieces and addition of a new RV32G BPF JIT compiler, from Luke Nelson. 8) Add gso_size context member to __sk_buff in order to be able to know whether a given skb is GSO or not, from Willem de Bruijn. 9) Add a new bpf_xdp_output() helper which reuses XDP's existing perf RB output implementation but can be called from tracepoint programs, from Eelco Chaudron. ==================== Signed-off-by: David S. Miller <[email protected]>
2020-03-13bpf: Add missing annotations for __bpf_prog_enter() and __bpf_prog_exit()Jules Irenge1-0/+2
Sparse reports a warning at __bpf_prog_enter() and __bpf_prog_exit() warning: context imbalance in __bpf_prog_enter() - wrong count at exit warning: context imbalance in __bpf_prog_exit() - unexpected unlock The root cause is the missing annotation at __bpf_prog_enter() and __bpf_prog_exit() Add the missing __acquires(RCU) annotation Add the missing __releases(RCU) annotation Signed-off-by: Jules Irenge <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-13bpf: Remove bpf_image treeJiri Olsa3-77/+12
Now that we have all the objects (bpf_prog, bpf_trampoline, bpf_dispatcher) linked in bpf_tree, there's no need to have separate bpf_image tree for images. Reverting the bpf_image tree together with struct bpf_image, because it's no longer needed. Also removing bpf_image_alloc function and adding the original bpf_jit_alloc_exec_page interface instead. The kernel_text_address function can now rely only on is_bpf_text_address, because it checks the bpf_tree that contains all the objects. Keeping bpf_image_ksym_add and bpf_image_ksym_del because they are useful wrappers with perf's ksymbol interface calls. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add dispatchers to kallsymsJiri Olsa1-0/+1
Adding dispatchers to kallsyms. It's displayed as bpf_dispatcher_<NAME> where NAME is the name of dispatcher. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add trampolines to kallsymsJiri Olsa1-0/+28
Adding trampolines to kallsyms. It's displayed as bpf_trampoline_<ID> [bpf] where ID is the BTF id of the trampoline function. Adding bpf_image_ksym_add/del functions that setup the start/end values and call KSYMBOL perf events handlers. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add bpf_ksym_add/del functionsJiri Olsa1-14/+19
Separating /proc/kallsyms add/del code and adding bpf_ksym_add/del functions for that. Moving bpf_prog_ksym_node_add/del functions to __bpf_ksym_add/del and changing their argument to 'struct bpf_ksym' object. This way we can call them for other bpf objects types like trampoline and dispatcher. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add prog flag to struct bpf_ksym objectJiri Olsa1-11/+11
Adding 'prog' bool flag to 'struct bpf_ksym' to mark that this object belongs to bpf_prog object. This change allows having bpf_prog objects together with other types (trampolines and dispatchers) in the single bpf_tree. It's used when searching for bpf_prog exception tables by the bpf_prog_ksym_find function, where we need to get the bpf_prog pointer. >From now we can safely add bpf_ksym support for trampoline or dispatcher objects, because we can differentiate them from bpf_prog objects. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add bpf_ksym_find functionJiri Olsa1-7/+15
Adding bpf_ksym_find function that is used bpf bpf address lookup functions: __bpf_address_lookup is_bpf_text_address while keeping bpf_prog_kallsyms_find to be used only for lookup of bpf_prog objects (will happen in following changes). Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Move ksym_tnode to bpf_ksymJiri Olsa1-14/+10
Moving ksym_tnode list node to 'struct bpf_ksym' object, so the symbol itself can be chained and used in other objects like bpf_trampoline and bpf_dispatcher. We need bpf_ksym object to be linked both in bpf_kallsyms via lnode for /proc/kallsyms and in bpf_tree via tnode for bpf address lookup functions like __bpf_address_lookup or bpf_prog_kallsyms_find. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Move lnode list node to struct bpf_ksymJiri Olsa1-11/+11
Adding lnode list node to 'struct bpf_ksym' object, so the struct bpf_ksym itself can be chained and used in other objects like bpf_trampoline and bpf_dispatcher. Changing iterator to bpf_ksym in bpf_get_kallsym function. The ksym->start is holding the prog->bpf_func value, so it's ok to use it as value in bpf_get_kallsym. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Song Liu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add name to struct bpf_ksymJiri Olsa2-8/+10
Adding name to 'struct bpf_ksym' object to carry the name of the symbol for bpf_prog, bpf_trampoline, bpf_dispatcher objects. The current benefit is that name is now generated only when the symbol is added to the list, so we don't need to generate it every time it's accessed. The future benefit is that we will have all the bpf objects symbols represented by struct bpf_ksym. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Song Liu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Add struct bpf_ksymJiri Olsa1-16/+12
Adding 'struct bpf_ksym' object that will carry the kallsym information for bpf symbol. Adding the start and end address to begin with. It will be used by bpf_prog, bpf_trampoline, bpf_dispatcher objects. The symbol_start/symbol_end values were originally used to sort bpf_prog objects. For the address displayed in /proc/kallsyms we are using prog->bpf_func value. I'm using the bpf_func value for program symbol start instead of the symbol_start, because it makes no difference for sorting bpf_prog objects and we can use it directly as an address to display it in /proc/kallsyms. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Song Liu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-13bpf: Abstract away entire bpf_link clean up procedureAndrii Nakryiko1-7/+11
Instead of requiring users to do three steps for cleaning up bpf_link, its anon_inode file, and unused fd, abstract that away into bpf_link_cleanup() helper. bpf_link_defunct() is removed, as it shouldn't be needed as an individual operation anymore. v1->v2: - keep bpf_link_cleanup() static for now (Daniel). Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
2020-03-12Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller10-55/+144
Minor overlapping changes, nothing serious. Signed-off-by: David S. Miller <[email protected]>
2020-03-12bpf: Add bpf_xdp_output() helperEelco Chaudron2-1/+6
Introduce new helper that reuses existing xdp perf_event output implementation, but can be called from raw_tracepoint programs that receive 'struct xdp_buff *' as a tracepoint argument. Signed-off-by: Eelco Chaudron <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: John Fastabend <[email protected]> Acked-by: Toke Høiland-Jørgensen <[email protected]> Link: https://lore.kernel.org/bpf/158348514556.2239.11050972434793741444.stgit@xdp-tutorial
2020-03-12bpf: Added new helper bpf_get_ns_current_pid_tgidCarlos Neira3-0/+48
New bpf helper bpf_get_ns_current_pid_tgid, This helper will return pid and tgid from current task which namespace matches dev_t and inode number provided, this will allows us to instrument a process inside a container. Signed-off-by: Carlos Neira <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-12Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds1-0/+4
Pull networking fixes from David Miller: "It looks like a decent sized set of fixes, but a lot of these are one liner off-by-one and similar type changes: 1) Fix netlink header pointer to calcular bad attribute offset reported to user. From Pablo Neira Ayuso. 2) Don't double clear PHY interrupts when ->did_interrupt is set, from Heiner Kallweit. 3) Add missing validation of various (devlink, nl802154, fib, etc.) attributes, from Jakub Kicinski. 4) Missing *pos increments in various netfilter seq_next ops, from Vasily Averin. 5) Missing break in of_mdiobus_register() loop, from Dajun Jin. 6) Don't double bump tx_dropped in veth driver, from Jiang Lidong. 7) Work around FMAN erratum A050385, from Madalin Bucur. 8) Make sure ARP header is pulled early enough in bonding driver, from Eric Dumazet. 9) Do a cond_resched() during multicast processing of ipvlan and macvlan, from Mahesh Bandewar. 10) Don't attach cgroups to unrelated sockets when in interrupt context, from Shakeel Butt. 11) Fix tpacket ring state management when encountering unknown GSO types. From Willem de Bruijn. 12) Fix MDIO bus PHY resume by checking mdio_bus_phy_may_suspend() only in the suspend context. From Heiner Kallweit" * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (112 commits) net: systemport: fix index check to avoid an array out of bounds access tc-testing: add ETS scheduler to tdc build configuration net: phy: fix MDIO bus PM PHY resuming net: hns3: clear port base VLAN when unload PF net: hns3: fix RMW issue for VLAN filter switch net: hns3: fix VF VLAN table entries inconsistent issue net: hns3: fix "tc qdisc del" failed issue taprio: Fix sending packets without dequeueing them net: mvmdio: avoid error message for optional IRQ net: dsa: mv88e6xxx: Add missing mask of ATU occupancy register net: memcg: fix lockdep splat in inet_csk_accept() s390/qeth: implement smarter resizing of the RX buffer pool s390/qeth: refactor buffer pool code s390/qeth: use page pointers to manage RX buffer pool seg6: fix SRv6 L2 tunnels to use IANA-assigned protocol number net: dsa: Don't instantiate phylink for CPU/DSA ports unless needed net/packet: tpacket_rcv: do not increment ring index on drop sxgbe: Fix off by one in samsung driver strncpy size arg net: caif: Add lockdep expression to RCU traversal primitive MAINTAINERS: remove Sathya Perla as Emulex NIC maintainer ...
2020-03-11Merge tag 'for-linus-2020-03-10' of ↵Linus Torvalds1-0/+10
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull thread fix from Christian Brauner: "This contains a single fix for a regression which was introduced when we introduced the ability to select a specific pid at process creation time. When this feature is requested, the error value will be set to -EPERM after exiting the pid allocation loop. This caused EPERM to be returned when e.g. the init process/child subreaper of the pid namespace has already died where we used to return ENOMEM before. The first patch here simply fixes the regression by unconditionally setting the return value back to ENOMEM again once we've successfully allocated the requested pid number. This should be easy to backport to v5.5. The second patch adds a comment explaining that we must keep returning ENOMEM since we've been doing it for a long time and have explicitly documented this behavior for userspace. This seemed worthwhile because we now have at least two separate example where people tried to change the return value to something other than ENOMEM (The first version of the regression fix did that too and the commit message links to an earlier patch that tried to do the same.). I have a simple regression test to make sure we catch this regression in the future but since that introduces a whole new selftest subdir and test files I'll keep this for v5.7" * tag 'for-linus-2020-03-10' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: pid: make ENOMEM return value more obvious pid: Fix error return value in some cases
2020-03-11Merge tag 'trace-v5.6-rc4' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull ftrace fix from Steven Rostedt: "Have ftrace lookup_rec() return a consistent record otherwise it can break live patching" * tag 'trace-v5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Return the first found result in lookup_rec()
2020-03-11ftrace: Return the first found result in lookup_rec()Artem Savkov1-0/+2
It appears that ip ranges can overlap so. In that case lookup_rec() returns whatever results it got last even if it found nothing in last searched page. This breaks an obscure livepatch late module patching usecase: - load livepatch - load the patched module - unload livepatch - try to load livepatch again To fix this return from lookup_rec() as soon as it found the record containing searched-for ip. This used to be this way prior lookup_rec() introduction. Link: http://lkml.kernel.org/r/[email protected] Cc: [email protected] Fixes: 7e16f581a817 ("ftrace: Separate out functionality from ftrace_location_range()") Signed-off-by: Artem Savkov <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-03-11bpf: Add bpf_link_new_file that doesn't install FDAndrii Nakryiko1-34/+88
Add bpf_link_new_file() API for cases when we need to ensure anon_inode is successfully created before we proceed with expensive BPF program attachment procedure, which will require equally (if not more so) expensive and potentially failing compensation detachment procedure just because anon_inode creation failed. This API allows to simplify code by ensuring first that anon_inode is created and after BPF program is attached proceed with fd_install() that can't fail. After anon_inode file is created, link can't be just kfree()'d anymore, because its destruction will be performed by deferred file_operations->release call. For this, bpf_link API required specifying two separate operations: release() and dealloc(), former performing detachment only, while the latter frees memory used by bpf_link itself. dealloc() needs to be specified, because struct bpf_link is frequently embedded into link type-specific container struct (e.g., struct bpf_raw_tp_link), so bpf_link itself doesn't know how to properly free the memory. In case when anon_inode file was successfully created, but subsequent BPF attachment failed, bpf_link needs to be marked as "defunct", so that file's release() callback will perform only memory deallocation, but no detachment. Convert raw tracepoint and tracing attachment to new API and eliminate detachment from error handling path. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: John Fastabend <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-10cgroup: memcg: net: do not associate sock with unrelated cgroupShakeel Butt1-0/+4
We are testing network memory accounting in our setup and noticed inconsistent network memory usage and often unrelated cgroups network usage correlates with testing workload. On further inspection, it seems like mem_cgroup_sk_alloc() and cgroup_sk_alloc() are broken in irq context specially for cgroup v1. mem_cgroup_sk_alloc() and cgroup_sk_alloc() can be called in irq context and kind of assumes that this can only happen from sk_clone_lock() and the source sock object has already associated cgroup. However in cgroup v1, where network memory accounting is opt-in, the source sock can be unassociated with any cgroup and the new cloned sock can get associated with unrelated interrupted cgroup. Cgroup v2 can also suffer if the source sock object was created by process in the root cgroup or if sk_alloc() is called in irq context. The fix is to just do nothing in interrupt. WARNING: Please note that about half of the TCP sockets are allocated from the IRQ context, so, memory used by such sockets will not be accouted by the memcg. The stack trace of mem_cgroup_sk_alloc() from IRQ-context: CPU: 70 PID: 12720 Comm: ssh Tainted: 5.6.0-smp-DEV #1 Hardware name: ... Call Trace: <IRQ> dump_stack+0x57/0x75 mem_cgroup_sk_alloc+0xe9/0xf0 sk_clone_lock+0x2a7/0x420 inet_csk_clone_lock+0x1b/0x110 tcp_create_openreq_child+0x23/0x3b0 tcp_v6_syn_recv_sock+0x88/0x730 tcp_check_req+0x429/0x560 tcp_v6_rcv+0x72d/0xa40 ip6_protocol_deliver_rcu+0xc9/0x400 ip6_input+0x44/0xd0 ? ip6_protocol_deliver_rcu+0x400/0x400 ip6_rcv_finish+0x71/0x80 ipv6_rcv+0x5b/0xe0 ? ip6_sublist_rcv+0x2e0/0x2e0 process_backlog+0x108/0x1e0 net_rx_action+0x26b/0x460 __do_softirq+0x104/0x2a6 do_softirq_own_stack+0x2a/0x40 </IRQ> do_softirq.part.19+0x40/0x50 __local_bh_enable_ip+0x51/0x60 ip6_finish_output2+0x23d/0x520 ? ip6table_mangle_hook+0x55/0x160 __ip6_finish_output+0xa1/0x100 ip6_finish_output+0x30/0xd0 ip6_output+0x73/0x120 ? __ip6_finish_output+0x100/0x100 ip6_xmit+0x2e3/0x600 ? ipv6_anycast_cleanup+0x50/0x50 ? inet6_csk_route_socket+0x136/0x1e0 ? skb_free_head+0x1e/0x30 inet6_csk_xmit+0x95/0xf0 __tcp_transmit_skb+0x5b4/0xb20 __tcp_send_ack.part.60+0xa3/0x110 tcp_send_ack+0x1d/0x20 tcp_rcv_state_process+0xe64/0xe80 ? tcp_v6_connect+0x5d1/0x5f0 tcp_v6_do_rcv+0x1b1/0x3f0 ? tcp_v6_do_rcv+0x1b1/0x3f0 __release_sock+0x7f/0xd0 release_sock+0x30/0xa0 __inet_stream_connect+0x1c3/0x3b0 ? prepare_to_wait+0xb0/0xb0 inet_stream_connect+0x3b/0x60 __sys_connect+0x101/0x120 ? __sys_getsockopt+0x11b/0x140 __x64_sys_connect+0x1a/0x20 do_syscall_64+0x51/0x200 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The stack trace of mem_cgroup_sk_alloc() from IRQ-context: Fixes: 2d7580738345 ("mm: memcontrol: consolidate cgroup socket tracking") Fixes: d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets") Signed-off-by: Shakeel Butt <[email protected]> Reviewed-by: Roman Gushchin <[email protected]> Signed-off-by: David S. Miller <[email protected]>
2020-03-10Merge branch 'for-5.6-fixes' of ↵Linus Torvalds2-14/+28
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: - cgroup.procs listing related fixes. It didn't interlock properly with exiting tasks leaving a short window where a cgroup has empty cgroup.procs but still can't be removed and misbehaved on short reads. - psi_show() crash fix on 32bit ino archs - Empty release_agent handling fix * 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup1: don't call release_agent when it is "" cgroup: fix psi_show() crash on 32bit ino archs cgroup: Iterate tasks that did not finish do_exit() cgroup: cgroup_procs_next should increase position index cgroup-v1: cgroup_pidlist_next should update position index
2020-03-10Merge branch 'for-5.6-fixes' of ↵Linus Torvalds1-6/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq Pull workqueue fixes from Tejun Heo: "Workqueue has been incorrectly round-robining per-cpu work items. Hillf's patch fixes that. The other patch documents memory-ordering properties of workqueue operations" * 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: don't use wq_select_unbound_cpu() for bound works workqueue: Document (some) memory-ordering properties of {queue,schedule}_work()
2020-03-10workqueue: don't use wq_select_unbound_cpu() for bound worksHillf Danton1-6/+8
wq_select_unbound_cpu() is designed for unbound workqueues only, but it's wrongly called when using a bound workqueue too. Fixing this ensures work queued to a bound workqueue with cpu=WORK_CPU_UNBOUND always runs on the local CPU. Before, that would happen only if wq_unbound_cpumask happened to include it (likely almost always the case), or was empty, or we got lucky with forced round-robin placement. So restricting /sys/devices/virtual/workqueue/cpumask to a small subset of a machine's CPUs would cause some bound work items to run unexpectedly there. Fixes: ef557180447f ("workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs") Cc: [email protected] # v4.5+ Signed-off-by: Hillf Danton <[email protected]> [dj: massage changelog] Signed-off-by: Daniel Jordan <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: [email protected] Signed-off-by: Tejun Heo <[email protected]>
2020-03-09pid: make ENOMEM return value more obviousChristian Brauner1-0/+8
The alloc_pid() codepath used to be simpler. With the introducation of the ability to choose specific pids in 49cb2fc42ce4 ("fork: extend clone3() to support setting a PID") it got more complex. It hasn't been super obvious that ENOMEM is returned when the pid namespace init process/child subreaper of the pid namespace has died. As can be seen from multiple attempts to improve this see e.g. [1] and most recently [2]. We regressed returning ENOMEM in [3] and [2] restored it. Let's add a comment on top explaining that this is historic and documented behavior and cannot easily be changed. [1]: 35f71bc0a09a ("fork: report pid reservation failure properly") [2]: b26ebfe12f34 ("pid: Fix error return value in some cases") [3]: 49cb2fc42ce4 ("fork: extend clone3() to support setting a PID") Signed-off-by: Christian Brauner <[email protected]>
2020-03-08pid: Fix error return value in some casesCorey Minyard1-0/+2
Recent changes to alloc_pid() allow the pid number to be specified on the command line. If set_tid_size is set, then the code scanning the levels will hard-set retval to -EPERM, overriding it's previous -ENOMEM value. After the code scanning the levels, there are error returns that do not set retval, assuming it is still set to -ENOMEM. So set retval back to -ENOMEM after scanning the levels. Fixes: 49cb2fc42ce4 ("fork: extend clone3() to support setting a PID") Signed-off-by: Corey Minyard <[email protected]> Acked-by: Christian Brauner <[email protected]> Cc: Andrei Vagin <[email protected]> Cc: Dmitry Safonov <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Adrian Reber <[email protected]> Cc: <[email protected]> # 5.5 Link: https://lore.kernel.org/r/[email protected] [[email protected]: fixup commit message] Signed-off-by: Christian Brauner <[email protected]>
2020-03-07Merge tag 'block-5.6-2020-03-07' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+4
Pull block fixes from Jens Axboe: "Here are a few fixes that should go into this release. This contains: - Revert of a bad bcache patch from this merge window - Removed unused function (Daniel) - Fixup for the blktrace fix from Jan from this release (Cengiz) - Fix of deeper level bfqq overwrite in BFQ (Carlo)" * tag 'block-5.6-2020-03-07' of git://git.kernel.dk/linux-block: block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group() blktrace: fix dereference after null check Revert "bcache: ignore pending signals when creating gc and allocator thread" block: Remove used kblockd_schedule_work_on()
2020-03-07Merge tag 'for-linus-2020-03-07' of ↵Linus Torvalds2-3/+3
gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux Pull thread fixes from Christian Brauner: "Here are a few hopefully uncontroversial fixes: - Use RCU_INIT_POINTER() when initializing rcu protected members in task_struct to fix sparse warnings. - Add pidfd_fdinfo_test binary to .gitignore file" * tag 'for-linus-2020-03-07' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux: selftests: pidfd: Add pidfd_fdinfo_test in .gitignore exit: Fix Sparse errors and warnings fork: Use RCU_INIT_POINTER() instead of rcu_access_pointer()
2020-03-05bpf: Fix bpf_prog_test_run_tracing for !CONFIG_NETKP Singh1-0/+7
test_run.o is not built when CONFIG_NET is not set and bpf_prog_test_run_tracing being referenced in bpf_trace.o causes the linker error: ld: kernel/trace/bpf_trace.o:(.rodata+0x38): undefined reference to `bpf_prog_test_run_tracing' Add a __weak function in bpf_trace.c to handle this. Fixes: da00d2f117a0 ("bpf: Add test ops for BPF_PROG_TYPE_TRACING") Signed-off-by: KP Singh <[email protected]> Reported-by: Randy Dunlap <[email protected]> Acked-by: Randy Dunlap <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-05bpf: Remove unnecessary CAP_MAC_ADMIN checkKP Singh1-10/+3
While well intentioned, checking CAP_MAC_ADMIN for attaching BPF_MODIFY_RETURN tracing programs to "security_" functions is not necessary as tracing BPF programs already require CAP_SYS_ADMIN. Fixes: 6ba43b761c41 ("bpf: Attachment verification for BPF_MODIFY_RETURN") Signed-off-by: KP Singh <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-05blktrace: fix dereference after null checkCengiz Can1-1/+4
There was a recent change in blktrace.c that added a RCU protection to `q->blk_trace` in order to fix a use-after-free issue during access. However the change missed an edge case that can lead to dereferencing of `bt` pointer even when it's NULL: Coverity static analyzer marked this as a FORWARD_NULL issue with CID 1460458. ``` /kernel/trace/blktrace.c: 1904 in sysfs_blk_trace_attr_store() 1898 ret = 0; 1899 if (bt == NULL) 1900 ret = blk_trace_setup_queue(q, bdev); 1901 1902 if (ret == 0) { 1903 if (attr == &dev_attr_act_mask) >>> CID 1460458: Null pointer dereferences (FORWARD_NULL) >>> Dereferencing null pointer "bt". 1904 bt->act_mask = value; 1905 else if (attr == &dev_attr_pid) 1906 bt->pid = value; 1907 else if (attr == &dev_attr_start_lba) 1908 bt->start_lba = value; 1909 else if (attr == &dev_attr_end_lba) ``` Added a reassignment with RCU annotation to fix the issue. Fixes: c780e86dd48 ("blktrace: Protect q->blk_trace with RCU") Cc: [email protected] Reviewed-by: Ming Lei <[email protected]> Reviewed-by: Bob Liu <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Cengiz Can <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
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