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-rw-r--r--arch/riscv/include/asm/cfi.h3
-rw-r--r--arch/riscv/kernel/cfi.c2
-rw-r--r--arch/x86/include/asm/cfi.h126
-rw-r--r--arch/x86/kernel/alternative.c87
-rw-r--r--arch/x86/kernel/cfi.c4
-rw-r--r--arch/x86/net/bpf_jit_comp.c134
-rw-r--r--include/asm-generic/Kbuild1
-rw-r--r--include/asm-generic/cfi.h5
-rw-r--r--include/linux/bpf.h27
-rw-r--r--include/linux/cfi.h12
-rw-r--r--kernel/bpf/bpf_struct_ops.c16
-rw-r--r--kernel/bpf/core.c25
-rw-r--r--kernel/bpf/cpumask.c8
-rw-r--r--kernel/bpf/helpers.c18
-rw-r--r--net/bpf/bpf_dummy_struct_ops.c31
-rw-r--r--net/bpf/test_run.c15
-rw-r--r--net/ipv4/bpf_tcp_ca.c69
17 files changed, 533 insertions, 50 deletions
diff --git a/arch/riscv/include/asm/cfi.h b/arch/riscv/include/asm/cfi.h
index 56bf9d69d5e3..8f7a62257044 100644
--- a/arch/riscv/include/asm/cfi.h
+++ b/arch/riscv/include/asm/cfi.h
@@ -7,8 +7,9 @@
*
* Copyright (C) 2023 Google LLC
*/
+#include <linux/bug.h>
-#include <linux/cfi.h>
+struct pt_regs;
#ifdef CONFIG_CFI_CLANG
enum bug_trap_type handle_cfi_failure(struct pt_regs *regs);
diff --git a/arch/riscv/kernel/cfi.c b/arch/riscv/kernel/cfi.c
index 820158d7a291..6ec9dbd7292e 100644
--- a/arch/riscv/kernel/cfi.c
+++ b/arch/riscv/kernel/cfi.c
@@ -4,7 +4,7 @@
*
* Copyright (C) 2023 Google LLC
*/
-#include <asm/cfi.h>
+#include <linux/cfi.h>
#include <asm/insn.h>
/*
diff --git a/arch/x86/include/asm/cfi.h b/arch/x86/include/asm/cfi.h
index 58dacd90daef..7cd752557905 100644
--- a/arch/x86/include/asm/cfi.h
+++ b/arch/x86/include/asm/cfi.h
@@ -7,16 +7,140 @@
*
* Copyright (C) 2022 Google LLC
*/
+#include <linux/bug.h>
+#include <asm/ibt.h>
-#include <linux/cfi.h>
+/*
+ * An overview of the various calling conventions...
+ *
+ * Traditional:
+ *
+ * foo:
+ * ... code here ...
+ * ret
+ *
+ * direct caller:
+ * call foo
+ *
+ * indirect caller:
+ * lea foo(%rip), %r11
+ * ...
+ * call *%r11
+ *
+ *
+ * IBT:
+ *
+ * foo:
+ * endbr64
+ * ... code here ...
+ * ret
+ *
+ * direct caller:
+ * call foo / call foo+4
+ *
+ * indirect caller:
+ * lea foo(%rip), %r11
+ * ...
+ * call *%r11
+ *
+ *
+ * kCFI:
+ *
+ * __cfi_foo:
+ * movl $0x12345678, %eax
+ * # 11 nops when CONFIG_CALL_PADDING
+ * foo:
+ * endbr64 # when IBT
+ * ... code here ...
+ * ret
+ *
+ * direct call:
+ * call foo # / call foo+4 when IBT
+ *
+ * indirect call:
+ * lea foo(%rip), %r11
+ * ...
+ * movl $(-0x12345678), %r10d
+ * addl -4(%r11), %r10d # -15 when CONFIG_CALL_PADDING
+ * jz 1f
+ * ud2
+ * 1:call *%r11
+ *
+ *
+ * FineIBT (builds as kCFI + CALL_PADDING + IBT + RETPOLINE and runtime patches into):
+ *
+ * __cfi_foo:
+ * endbr64
+ * subl 0x12345678, %r10d
+ * jz foo
+ * ud2
+ * nop
+ * foo:
+ * osp nop3 # was endbr64
+ * ... code here ...
+ * ret
+ *
+ * direct caller:
+ * call foo / call foo+4
+ *
+ * indirect caller:
+ * lea foo(%rip), %r11
+ * ...
+ * movl $0x12345678, %r10d
+ * subl $16, %r11
+ * nop4
+ * call *%r11
+ *
+ */
+enum cfi_mode {
+ CFI_DEFAULT, /* FineIBT if hardware has IBT, otherwise kCFI */
+ CFI_OFF, /* Taditional / IBT depending on .config */
+ CFI_KCFI, /* Optionally CALL_PADDING, IBT, RETPOLINE */
+ CFI_FINEIBT, /* see arch/x86/kernel/alternative.c */
+};
+
+extern enum cfi_mode cfi_mode;
+
+struct pt_regs;
#ifdef CONFIG_CFI_CLANG
enum bug_trap_type handle_cfi_failure(struct pt_regs *regs);
+#define __bpfcall
+extern u32 cfi_bpf_hash;
+extern u32 cfi_bpf_subprog_hash;
+
+static inline int cfi_get_offset(void)
+{
+ switch (cfi_mode) {
+ case CFI_FINEIBT:
+ return 16;
+ case CFI_KCFI:
+ if (IS_ENABLED(CONFIG_CALL_PADDING))
+ return 16;
+ return 5;
+ default:
+ return 0;
+ }
+}
+#define cfi_get_offset cfi_get_offset
+
+extern u32 cfi_get_func_hash(void *func);
+
#else
static inline enum bug_trap_type handle_cfi_failure(struct pt_regs *regs)
{
return BUG_TRAP_TYPE_NONE;
}
+#define cfi_bpf_hash 0U
+#define cfi_bpf_subprog_hash 0U
+static inline u32 cfi_get_func_hash(void *func)
+{
+ return 0;
+}
#endif /* CONFIG_CFI_CLANG */
+#if HAS_KERNEL_IBT == 1
+#define CFI_NOSEAL(x) asm(IBT_NOSEAL(__stringify(x)))
+#endif
+
#endif /* _ASM_X86_CFI_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 73be3931e4f0..49c2a62ba5e4 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -30,6 +30,7 @@
#include <asm/fixmap.h>
#include <asm/paravirt.h>
#include <asm/asm-prototypes.h>
+#include <asm/cfi.h>
int __read_mostly alternatives_patched;
@@ -832,15 +833,82 @@ void __init_or_module apply_seal_endbr(s32 *start, s32 *end) { }
#endif /* CONFIG_X86_KERNEL_IBT */
#ifdef CONFIG_FINEIBT
+#define __CFI_DEFAULT CFI_DEFAULT
+#elif defined(CONFIG_CFI_CLANG)
+#define __CFI_DEFAULT CFI_KCFI
+#else
+#define __CFI_DEFAULT CFI_OFF
+#endif
-enum cfi_mode {
- CFI_DEFAULT,
- CFI_OFF,
- CFI_KCFI,
- CFI_FINEIBT,
-};
+enum cfi_mode cfi_mode __ro_after_init = __CFI_DEFAULT;
+
+#ifdef CONFIG_CFI_CLANG
+struct bpf_insn;
+
+/* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */
+extern unsigned int __bpf_prog_runX(const void *ctx,
+ const struct bpf_insn *insn);
+
+/*
+ * Force a reference to the external symbol so the compiler generates
+ * __kcfi_typid.
+ */
+__ADDRESSABLE(__bpf_prog_runX);
+
+/* u32 __ro_after_init cfi_bpf_hash = __kcfi_typeid___bpf_prog_runX; */
+asm (
+" .pushsection .data..ro_after_init,\"aw\",@progbits \n"
+" .type cfi_bpf_hash,@object \n"
+" .globl cfi_bpf_hash \n"
+" .p2align 2, 0x0 \n"
+"cfi_bpf_hash: \n"
+" .long __kcfi_typeid___bpf_prog_runX \n"
+" .size cfi_bpf_hash, 4 \n"
+" .popsection \n"
+);
+
+/* Must match bpf_callback_t */
+extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64);
+
+__ADDRESSABLE(__bpf_callback_fn);
+
+/* u32 __ro_after_init cfi_bpf_subprog_hash = __kcfi_typeid___bpf_callback_fn; */
+asm (
+" .pushsection .data..ro_after_init,\"aw\",@progbits \n"
+" .type cfi_bpf_subprog_hash,@object \n"
+" .globl cfi_bpf_subprog_hash \n"
+" .p2align 2, 0x0 \n"
+"cfi_bpf_subprog_hash: \n"
+" .long __kcfi_typeid___bpf_callback_fn \n"
+" .size cfi_bpf_subprog_hash, 4 \n"
+" .popsection \n"
+);
+
+u32 cfi_get_func_hash(void *func)
+{
+ u32 hash;
+
+ func -= cfi_get_offset();
+ switch (cfi_mode) {
+ case CFI_FINEIBT:
+ func += 7;
+ break;
+ case CFI_KCFI:
+ func += 1;
+ break;
+ default:
+ return 0;
+ }
+
+ if (get_kernel_nofault(hash, func))
+ return 0;
+
+ return hash;
+}
+#endif
+
+#ifdef CONFIG_FINEIBT
-static enum cfi_mode cfi_mode __ro_after_init = CFI_DEFAULT;
static bool cfi_rand __ro_after_init = true;
static u32 cfi_seed __ro_after_init;
@@ -1149,8 +1217,11 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
goto err;
if (cfi_rand) {
- if (builtin)
+ if (builtin) {
cfi_seed = get_random_u32();
+ cfi_bpf_hash = cfi_rehash(cfi_bpf_hash);
+ cfi_bpf_subprog_hash = cfi_rehash(cfi_bpf_subprog_hash);
+ }
ret = cfi_rand_preamble(start_cfi, end_cfi);
if (ret)
diff --git a/arch/x86/kernel/cfi.c b/arch/x86/kernel/cfi.c
index 8674a5c0c031..e6bf78fac146 100644
--- a/arch/x86/kernel/cfi.c
+++ b/arch/x86/kernel/cfi.c
@@ -4,10 +4,10 @@
*
* Copyright (C) 2022 Google LLC
*/
-#include <asm/cfi.h>
+#include <linux/string.h>
+#include <linux/cfi.h>
#include <asm/insn.h>
#include <asm/insn-eval.h>
-#include <linux/string.h>
/*
* Returns the target address and the expected type when regs->ip points
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index af4a5de7d93a..c89a4abdd726 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -17,6 +17,7 @@
#include <asm/nospec-branch.h>
#include <asm/text-patching.h>
#include <asm/unwind.h>
+#include <asm/cfi.h>
static bool all_callee_regs_used[4] = {true, true, true, true};
@@ -51,9 +52,11 @@ static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
#ifdef CONFIG_X86_KERNEL_IBT
-#define EMIT_ENDBR() EMIT(gen_endbr(), 4)
+#define EMIT_ENDBR() EMIT(gen_endbr(), 4)
+#define EMIT_ENDBR_POISON() EMIT(gen_endbr_poison(), 4)
#else
#define EMIT_ENDBR()
+#define EMIT_ENDBR_POISON()
#endif
static bool is_imm8(int value)
@@ -305,6 +308,69 @@ static void pop_callee_regs(u8 **pprog, bool *callee_regs_used)
}
/*
+ * Emit the various CFI preambles, see asm/cfi.h and the comments about FineIBT
+ * in arch/x86/kernel/alternative.c
+ */
+
+static void emit_fineibt(u8 **pprog, u32 hash)
+{
+ u8 *prog = *pprog;
+
+ EMIT_ENDBR();
+ EMIT3_off32(0x41, 0x81, 0xea, hash); /* subl $hash, %r10d */
+ EMIT2(0x74, 0x07); /* jz.d8 +7 */
+ EMIT2(0x0f, 0x0b); /* ud2 */
+ EMIT1(0x90); /* nop */
+ EMIT_ENDBR_POISON();
+
+ *pprog = prog;
+}
+
+static void emit_kcfi(u8 **pprog, u32 hash)
+{
+ u8 *prog = *pprog;
+
+ EMIT1_off32(0xb8, hash); /* movl $hash, %eax */
+#ifdef CONFIG_CALL_PADDING
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+ EMIT1(0x90);
+#endif
+ EMIT_ENDBR();
+
+ *pprog = prog;
+}
+
+static void emit_cfi(u8 **pprog, u32 hash)
+{
+ u8 *prog = *pprog;
+
+ switch (cfi_mode) {
+ case CFI_FINEIBT:
+ emit_fineibt(&prog, hash);
+ break;
+
+ case CFI_KCFI:
+ emit_kcfi(&prog, hash);
+ break;
+
+ default:
+ EMIT_ENDBR();
+ break;
+ }
+
+ *pprog = prog;
+}
+
+/*
* Emit x86-64 prologue code for BPF program.
* bpf_tail_call helper will skip the first X86_TAIL_CALL_OFFSET bytes
* while jumping to another program
@@ -315,10 +381,10 @@ static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf,
{
u8 *prog = *pprog;
+ emit_cfi(&prog, is_subprog ? cfi_bpf_subprog_hash : cfi_bpf_hash);
/* BPF trampoline can be made to work without these nops,
* but let's waste 5 bytes for now and optimize later
*/
- EMIT_ENDBR();
memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
prog += X86_PATCH_SIZE;
if (!ebpf_from_cbpf) {
@@ -2442,10 +2508,19 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
u8 *prog;
bool save_ret;
+ /*
+ * F_INDIRECT is only compatible with F_RET_FENTRY_RET, it is
+ * explicitly incompatible with F_CALL_ORIG | F_SKIP_FRAME | F_IP_ARG
+ * because @func_addr.
+ */
+ WARN_ON_ONCE((flags & BPF_TRAMP_F_INDIRECT) &&
+ (flags & ~(BPF_TRAMP_F_INDIRECT | BPF_TRAMP_F_RET_FENTRY_RET)));
+
/* extra registers for struct arguments */
- for (i = 0; i < m->nr_args; i++)
+ for (i = 0; i < m->nr_args; i++) {
if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
nr_regs += (m->arg_size[i] + 7) / 8 - 1;
+ }
/* x86-64 supports up to MAX_BPF_FUNC_ARGS arguments. 1-6
* are passed through regs, the remains are through stack.
@@ -2528,20 +2603,27 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
prog = rw_image;
- EMIT_ENDBR();
- /*
- * This is the direct-call trampoline, as such it needs accounting
- * for the __fentry__ call.
- */
- x86_call_depth_emit_accounting(&prog, NULL);
+ if (flags & BPF_TRAMP_F_INDIRECT) {
+ /*
+ * Indirect call for bpf_struct_ops
+ */
+ emit_cfi(&prog, cfi_get_func_hash(func_addr));
+ } else {
+ /*
+ * Direct-call fentry stub, as such it needs accounting for the
+ * __fentry__ call.
+ */
+ x86_call_depth_emit_accounting(&prog, NULL);
+ }
EMIT1(0x55); /* push rbp */
EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
- if (!is_imm8(stack_size))
+ if (!is_imm8(stack_size)) {
/* sub rsp, stack_size */
EMIT3_off32(0x48, 0x81, 0xEC, stack_size);
- else
+ } else {
/* sub rsp, stack_size */
EMIT4(0x48, 0x83, 0xEC, stack_size);
+ }
if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
EMIT1(0x50); /* push rax */
/* mov QWORD PTR [rbp - rbx_off], rbx */
@@ -2575,10 +2657,11 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
}
}
- if (fentry->nr_links)
+ if (fentry->nr_links) {
if (invoke_bpf(m, &prog, fentry, regs_off, run_ctx_off,
flags & BPF_TRAMP_F_RET_FENTRY_RET, image, rw_image))
return -EINVAL;
+ }
if (fmod_ret->nr_links) {
branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *),
@@ -2597,11 +2680,12 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
restore_regs(m, &prog, regs_off);
save_args(m, &prog, arg_stack_off, true);
- if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
+ if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) {
/* Before calling the original function, restore the
* tail_call_cnt from stack to rax.
*/
RESTORE_TAIL_CALL_CNT(stack_size);
+ }
if (flags & BPF_TRAMP_F_ORIG_STACK) {
emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, 8);
@@ -2630,17 +2714,19 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
/* Update the branches saved in invoke_bpf_mod_ret with the
* aligned address of do_fexit.
*/
- for (i = 0; i < fmod_ret->nr_links; i++)
+ for (i = 0; i < fmod_ret->nr_links; i++) {
emit_cond_near_jump(&branches[i], image + (prog - (u8 *)rw_image),
image + (branches[i] - (u8 *)rw_image), X86_JNE);
+ }
}
- if (fexit->nr_links)
+ if (fexit->nr_links) {
if (invoke_bpf(m, &prog, fexit, regs_off, run_ctx_off,
false, image, rw_image)) {
ret = -EINVAL;
goto cleanup;
}
+ }
if (flags & BPF_TRAMP_F_RESTORE_REGS)
restore_regs(m, &prog, regs_off);
@@ -2657,11 +2743,12 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
ret = -EINVAL;
goto cleanup;
}
- } else if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
+ } else if (flags & BPF_TRAMP_F_TAIL_CALL_CTX) {
/* Before running the original function, restore the
* tail_call_cnt from stack to rax.
*/
RESTORE_TAIL_CALL_CNT(stack_size);
+ }
/* restore return value of orig_call or fentry prog back into RAX */
if (save_ret)
@@ -2669,9 +2756,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, -rbx_off);
EMIT1(0xC9); /* leave */
- if (flags & BPF_TRAMP_F_SKIP_FRAME)
+ if (flags & BPF_TRAMP_F_SKIP_FRAME) {
/* skip our return address and return to parent */
EMIT4(0x48, 0x83, 0xC4, 8); /* add rsp, 8 */
+ }
emit_return(&prog, image + (prog - (u8 *)rw_image));
/* Make sure the trampoline generation logic doesn't overflow */
if (WARN_ON_ONCE(prog > (u8 *)rw_image_end - BPF_INSN_SAFETY)) {
@@ -3013,9 +3101,16 @@ out_image:
jit_data->header = header;
jit_data->rw_header = rw_header;
}
- prog->bpf_func = (void *)image;
+ /*
+ * ctx.prog_offset is used when CFI preambles put code *before*
+ * the function. See emit_cfi(). For FineIBT specifically this code
+ * can also be executed and bpf_prog_kallsyms_add() will
+ * generate an additional symbol to cover this, hence also
+ * decrement proglen.
+ */
+ prog->bpf_func = (void *)image + cfi_get_offset();
prog->jited = 1;
- prog->jited_len = proglen;
+ prog->jited_len = proglen - cfi_get_offset();
} else {
prog = orig_prog;
}
@@ -3070,6 +3165,7 @@ void bpf_jit_free(struct bpf_prog *prog)
kvfree(jit_data->addrs);
kfree(jit_data);
}
+ prog->bpf_func = (void *)prog->bpf_func - cfi_get_offset();
hdr = bpf_jit_binary_pack_hdr(prog);
bpf_jit_binary_pack_free(hdr, NULL);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index def242528b1d..d436bee4d129 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -11,6 +11,7 @@ mandatory-y += bitops.h
mandatory-y += bug.h
mandatory-y += bugs.h
mandatory-y += cacheflush.h
+mandatory-y += cfi.h
mandatory-y += checksum.h
mandatory-y += compat.h
mandatory-y += current.h
diff --git a/include/asm-generic/cfi.h b/include/asm-generic/cfi.h
new file mode 100644
index 000000000000..41fac3537bf9
--- /dev/null
+++ b/include/asm-generic/cfi.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_GENERIC_CFI_H
+#define __ASM_GENERIC_CFI_H
+
+#endif /* __ASM_GENERIC_CFI_H */
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c87c608a3689..5e694934cf37 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -29,6 +29,7 @@
#include <linux/rcupdate_trace.h>
#include <linux/static_call.h>
#include <linux/memcontrol.h>
+#include <linux/cfi.h>
struct bpf_verifier_env;
struct bpf_verifier_log;
@@ -1059,6 +1060,17 @@ struct btf_func_model {
*/
#define BPF_TRAMP_F_TAIL_CALL_CTX BIT(7)
+/*
+ * Indicate the trampoline should be suitable to receive indirect calls;
+ * without this indirectly calling the generated code can result in #UD/#CP,
+ * depending on the CFI options.
+ *
+ * Used by bpf_struct_ops.
+ *
+ * Incompatible with FENTRY usage, overloads @func_addr argument.
+ */
+#define BPF_TRAMP_F_INDIRECT BIT(8)
+
/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50
* bytes on x86.
*/
@@ -1211,7 +1223,11 @@ struct bpf_dispatcher {
#endif
};
-static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
+#ifndef __bpfcall
+#define __bpfcall __nocfi
+#endif
+
+static __always_inline __bpfcall unsigned int bpf_dispatcher_nop_func(
const void *ctx,
const struct bpf_insn *insnsi,
bpf_func_t bpf_func)
@@ -1303,7 +1319,7 @@ int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_func
#define DEFINE_BPF_DISPATCHER(name) \
__BPF_DISPATCHER_SC(name); \
- noinline __nocfi unsigned int bpf_dispatcher_##name##_func( \
+ noinline __bpfcall unsigned int bpf_dispatcher_##name##_func( \
const void *ctx, \
const struct bpf_insn *insnsi, \
bpf_func_t bpf_func) \
@@ -1453,6 +1469,9 @@ struct bpf_prog_aux {
struct bpf_kfunc_desc_tab *kfunc_tab;
struct bpf_kfunc_btf_tab *kfunc_btf_tab;
u32 size_poke_tab;
+#ifdef CONFIG_FINEIBT
+ struct bpf_ksym ksym_prefix;
+#endif
struct bpf_ksym ksym;
const struct bpf_prog_ops *ops;
struct bpf_map **used_maps;
@@ -1465,7 +1484,7 @@ struct bpf_prog_aux {
int cgroup_atype; /* enum cgroup_bpf_attach_type */
struct bpf_map *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE];
char name[BPF_OBJ_NAME_LEN];
- unsigned int (*bpf_exception_cb)(u64 cookie, u64 sp, u64 bp);
+ u64 (*bpf_exception_cb)(u64 cookie, u64 sp, u64 bp, u64, u64);
#ifdef CONFIG_SECURITY
void *security;
#endif
@@ -1689,6 +1708,7 @@ struct bpf_struct_ops {
struct btf_func_model func_models[BPF_STRUCT_OPS_MAX_NR_MEMBERS];
u32 type_id;
u32 value_id;
+ void *cfi_stubs;
};
#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
@@ -1702,6 +1722,7 @@ int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
struct bpf_tramp_link *link,
const struct btf_func_model *model,
+ void *stub_func,
void *image, void *image_end);
static inline bool bpf_try_module_get(const void *data, struct module *owner)
{
diff --git a/include/linux/cfi.h b/include/linux/cfi.h
index 3552ec82b725..f0df518e11dd 100644
--- a/include/linux/cfi.h
+++ b/include/linux/cfi.h
@@ -9,6 +9,14 @@
#include <linux/bug.h>
#include <linux/module.h>
+#include <asm/cfi.h>
+
+#ifndef cfi_get_offset
+static inline int cfi_get_offset(void)
+{
+ return 0;
+}
+#endif
#ifdef CONFIG_CFI_CLANG
enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
@@ -38,4 +46,8 @@ static inline void module_cfi_finalize(const Elf_Ehdr *hdr,
#endif /* CONFIG_ARCH_USES_CFI_TRAPS */
#endif /* CONFIG_MODULES */
+#ifndef CFI_NOSEAL
+#define CFI_NOSEAL(x)
+#endif
+
#endif /* _LINUX_CFI_H */
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 4d53c53fc5aa..02068bd0e4d9 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -352,17 +352,16 @@ const struct bpf_link_ops bpf_struct_ops_link_lops = {
int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
struct bpf_tramp_link *link,
const struct btf_func_model *model,
- void *image, void *image_end)
+ void *stub_func, void *image, void *image_end)
{
- u32 flags;
+ u32 flags = BPF_TRAMP_F_INDIRECT;
int size;
tlinks[BPF_TRAMP_FENTRY].links[0] = link;
tlinks[BPF_TRAMP_FENTRY].nr_links = 1;
- /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
- * and it must be used alone.
- */
- flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
+
+ if (model->ret_size > 0)
+ flags |= BPF_TRAMP_F_RET_FENTRY_RET;
size = arch_bpf_trampoline_size(model, flags, tlinks, NULL);
if (size < 0)
@@ -370,7 +369,7 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
if (size > (unsigned long)image_end - (unsigned long)image)
return -E2BIG;
return arch_prepare_bpf_trampoline(NULL, image, image_end,
- model, flags, tlinks, NULL);
+ model, flags, tlinks, stub_func);
}
static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
@@ -504,11 +503,12 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
err = bpf_struct_ops_prepare_trampoline(tlinks, link,
&st_ops->func_models[i],
+ *(void **)(st_ops->cfi_stubs + moff),
image, image_end);
if (err < 0)
goto reset_unlock;
- *(void **)(kdata + moff) = image;
+ *(void **)(kdata + moff) = image + cfi_get_offset();
image += err;
/* put prog_id to udata */
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index c34513d645c4..5aa6863ac33b 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -121,6 +121,9 @@ struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flag
#endif
INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
+#ifdef CONFIG_FINEIBT
+ INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode);
+#endif
mutex_init(&fp->aux->used_maps_mutex);
mutex_init(&fp->aux->dst_mutex);
@@ -683,6 +686,23 @@ void bpf_prog_kallsyms_add(struct bpf_prog *fp)
fp->aux->ksym.prog = true;
bpf_ksym_add(&fp->aux->ksym);
+
+#ifdef CONFIG_FINEIBT
+ /*
+ * When FineIBT, code in the __cfi_foo() symbols can get executed
+ * and hence unwinder needs help.
+ */
+ if (cfi_mode != CFI_FINEIBT)
+ return;
+
+ snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN,
+ "__cfi_%s", fp->aux->ksym.name);
+
+ fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16;
+ fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func;
+
+ bpf_ksym_add(&fp->aux->ksym_prefix);
+#endif
}
void bpf_prog_kallsyms_del(struct bpf_prog *fp)
@@ -691,6 +711,11 @@ void bpf_prog_kallsyms_del(struct bpf_prog *fp)
return;
bpf_ksym_del(&fp->aux->ksym);
+#ifdef CONFIG_FINEIBT
+ if (cfi_mode != CFI_FINEIBT)
+ return;
+ bpf_ksym_del(&fp->aux->ksym_prefix);
+#endif
}
static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
index 7499b7d8c06f..2e73533a3811 100644
--- a/kernel/bpf/cpumask.c
+++ b/kernel/bpf/cpumask.c
@@ -96,6 +96,12 @@ __bpf_kfunc void bpf_cpumask_release(struct bpf_cpumask *cpumask)
migrate_enable();
}
+__bpf_kfunc void bpf_cpumask_release_dtor(void *cpumask)
+{
+ bpf_cpumask_release(cpumask);
+}
+CFI_NOSEAL(bpf_cpumask_release_dtor);
+
/**
* bpf_cpumask_first() - Get the index of the first nonzero bit in the cpumask.
* @cpumask: The cpumask being queried.
@@ -453,7 +459,7 @@ static const struct btf_kfunc_id_set cpumask_kfunc_set = {
BTF_ID_LIST(cpumask_dtor_ids)
BTF_ID(struct, bpf_cpumask)
-BTF_ID(func, bpf_cpumask_release)
+BTF_ID(func, bpf_cpumask_release_dtor)
static int __init cpumask_kfunc_init(void)
{
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index b0b485126a76..07fd4b5704f3 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2150,6 +2150,12 @@ __bpf_kfunc void bpf_task_release(struct task_struct *p)
put_task_struct_rcu_user(p);
}
+__bpf_kfunc void bpf_task_release_dtor(void *p)
+{
+ put_task_struct_rcu_user(p);
+}
+CFI_NOSEAL(bpf_task_release_dtor);
+
#ifdef CONFIG_CGROUPS
/**
* bpf_cgroup_acquire - Acquire a reference to a cgroup. A cgroup acquired by
@@ -2174,6 +2180,12 @@ __bpf_kfunc void bpf_cgroup_release(struct cgroup *cgrp)
cgroup_put(cgrp);
}
+__bpf_kfunc void bpf_cgroup_release_dtor(void *cgrp)
+{
+ cgroup_put(cgrp);
+}
+CFI_NOSEAL(bpf_cgroup_release_dtor);
+
/**
* bpf_cgroup_ancestor - Perform a lookup on an entry in a cgroup's ancestor
* array. A cgroup returned by this kfunc which is not subsequently stored in a
@@ -2525,7 +2537,7 @@ __bpf_kfunc void bpf_throw(u64 cookie)
* which skips compiler generated instrumentation to do the same.
*/
kasan_unpoison_task_stack_below((void *)(long)ctx.sp);
- ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp);
+ ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp, 0, 0);
WARN(1, "A call to BPF exception callback should never return\n");
}
@@ -2570,10 +2582,10 @@ static const struct btf_kfunc_id_set generic_kfunc_set = {
BTF_ID_LIST(generic_dtor_ids)
BTF_ID(struct, task_struct)
-BTF_ID(func, bpf_task_release)
+BTF_ID(func, bpf_task_release_dtor)
#ifdef CONFIG_CGROUPS
BTF_ID(struct, cgroup)
-BTF_ID(func, bpf_cgroup_release)
+BTF_ID(func, bpf_cgroup_release_dtor)
#endif
BTF_SET8_START(common_btf_ids)
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index 2748f9d77b18..8906f7bdf4a9 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -12,6 +12,11 @@ extern struct bpf_struct_ops bpf_bpf_dummy_ops;
/* A common type for test_N with return value in bpf_dummy_ops */
typedef int (*dummy_ops_test_ret_fn)(struct bpf_dummy_ops_state *state, ...);
+static int dummy_ops_test_ret_function(struct bpf_dummy_ops_state *state, ...)
+{
+ return 0;
+}
+
struct bpf_dummy_ops_test_args {
u64 args[MAX_BPF_FUNC_ARGS];
struct bpf_dummy_ops_state state;
@@ -62,7 +67,7 @@ static int dummy_ops_copy_args(struct bpf_dummy_ops_test_args *args)
static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args)
{
- dummy_ops_test_ret_fn test = (void *)image;
+ dummy_ops_test_ret_fn test = (void *)image + cfi_get_offset();
struct bpf_dummy_ops_state *state = NULL;
/* state needs to be NULL if args[0] is 0 */
@@ -119,6 +124,7 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
op_idx = prog->expected_attach_type;
err = bpf_struct_ops_prepare_trampoline(tlinks, link,
&st_ops->func_models[op_idx],
+ &dummy_ops_test_ret_function,
image, image + PAGE_SIZE);
if (err < 0)
goto out;
@@ -219,6 +225,28 @@ static void bpf_dummy_unreg(void *kdata)
{
}
+static int bpf_dummy_test_1(struct bpf_dummy_ops_state *cb)
+{
+ return 0;
+}
+
+static int bpf_dummy_test_2(struct bpf_dummy_ops_state *cb, int a1, unsigned short a2,
+ char a3, unsigned long a4)
+{
+ return 0;
+}
+
+static int bpf_dummy_test_sleepable(struct bpf_dummy_ops_state *cb)
+{
+ return 0;
+}
+
+static struct bpf_dummy_ops __bpf_bpf_dummy_ops = {
+ .test_1 = bpf_dummy_test_1,
+ .test_2 = bpf_dummy_test_2,
+ .test_sleepable = bpf_dummy_test_sleepable,
+};
+
struct bpf_struct_ops bpf_bpf_dummy_ops = {
.verifier_ops = &bpf_dummy_verifier_ops,
.init = bpf_dummy_init,
@@ -227,4 +255,5 @@ struct bpf_struct_ops bpf_bpf_dummy_ops = {
.reg = bpf_dummy_reg,
.unreg = bpf_dummy_unreg,
.name = "bpf_dummy_ops",
+ .cfi_stubs = &__bpf_bpf_dummy_ops,
};
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 711cf5d59816..dfd919374017 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -600,10 +600,21 @@ __bpf_kfunc void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
refcount_dec(&p->cnt);
}
+__bpf_kfunc void bpf_kfunc_call_test_release_dtor(void *p)
+{
+ bpf_kfunc_call_test_release(p);
+}
+CFI_NOSEAL(bpf_kfunc_call_test_release_dtor);
+
__bpf_kfunc void bpf_kfunc_call_memb_release(struct prog_test_member *p)
{
}
+__bpf_kfunc void bpf_kfunc_call_memb_release_dtor(void *p)
+{
+}
+CFI_NOSEAL(bpf_kfunc_call_memb_release_dtor);
+
__bpf_kfunc_end_defs();
BTF_SET8_START(bpf_test_modify_return_ids)
@@ -1671,9 +1682,9 @@ static const struct btf_kfunc_id_set bpf_prog_test_kfunc_set = {
BTF_ID_LIST(bpf_prog_test_dtor_kfunc_ids)
BTF_ID(struct, prog_test_ref_kfunc)
-BTF_ID(func, bpf_kfunc_call_test_release)
+BTF_ID(func, bpf_kfunc_call_test_release_dtor)
BTF_ID(struct, prog_test_member)
-BTF_ID(func, bpf_kfunc_call_memb_release)
+BTF_ID(func, bpf_kfunc_call_memb_release_dtor)
static int __init bpf_prog_test_run_init(void)
{
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index c7bbd8f3c708..634cfafa583d 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -271,6 +271,74 @@ static int bpf_tcp_ca_validate(void *kdata)
return tcp_validate_congestion_control(kdata);
}
+static u32 bpf_tcp_ca_ssthresh(struct sock *sk)
+{
+ return 0;
+}
+
+static void bpf_tcp_ca_cong_avoid(struct sock *sk, u32 ack, u32 acked)
+{
+}
+
+static void bpf_tcp_ca_set_state(struct sock *sk, u8 new_state)
+{
+}
+
+static void bpf_tcp_ca_cwnd_event(struct sock *sk, enum tcp_ca_event ev)
+{
+}
+
+static void bpf_tcp_ca_in_ack_event(struct sock *sk, u32 flags)
+{
+}
+
+static void bpf_tcp_ca_pkts_acked(struct sock *sk, const struct ack_sample *sample)
+{
+}
+
+static u32 bpf_tcp_ca_min_tso_segs(struct sock *sk)
+{
+ return 0;
+}
+
+static void bpf_tcp_ca_cong_control(struct sock *sk, const struct rate_sample *rs)
+{
+}
+
+static u32 bpf_tcp_ca_undo_cwnd(struct sock *sk)
+{
+ return 0;
+}
+
+static u32 bpf_tcp_ca_sndbuf_expand(struct sock *sk)
+{
+ return 0;
+}
+
+static void __bpf_tcp_ca_init(struct sock *sk)
+{
+}
+
+static void __bpf_tcp_ca_release(struct sock *sk)
+{
+}
+
+static struct tcp_congestion_ops __bpf_ops_tcp_congestion_ops = {
+ .ssthresh = bpf_tcp_ca_ssthresh,
+ .cong_avoid = bpf_tcp_ca_cong_avoid,
+ .set_state = bpf_tcp_ca_set_state,
+ .cwnd_event = bpf_tcp_ca_cwnd_event,
+ .in_ack_event = bpf_tcp_ca_in_ack_event,
+ .pkts_acked = bpf_tcp_ca_pkts_acked,
+ .min_tso_segs = bpf_tcp_ca_min_tso_segs,
+ .cong_control = bpf_tcp_ca_cong_control,
+ .undo_cwnd = bpf_tcp_ca_undo_cwnd,
+ .sndbuf_expand = bpf_tcp_ca_sndbuf_expand,
+
+ .init = __bpf_tcp_ca_init,
+ .release = __bpf_tcp_ca_release,
+};
+
struct bpf_struct_ops bpf_tcp_congestion_ops = {
.verifier_ops = &bpf_tcp_ca_verifier_ops,
.reg = bpf_tcp_ca_reg,
@@ -281,6 +349,7 @@ struct bpf_struct_ops bpf_tcp_congestion_ops = {
.init = bpf_tcp_ca_init,
.validate = bpf_tcp_ca_validate,
.name = "tcp_congestion_ops",
+ .cfi_stubs = &__bpf_ops_tcp_congestion_ops,
};
static int __init bpf_tcp_ca_kfunc_init(void)
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