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-rw-r--r--kernel/bpf/core.c266
1 files changed, 129 insertions, 137 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index d315b393abdd..9f1493705f40 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -31,6 +31,7 @@
#include <linux/rbtree_latch.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>
+#include <linux/perf_event.h>
#include <asm/unaligned.h>
@@ -218,47 +219,84 @@ int bpf_prog_calc_tag(struct bpf_prog *fp)
return 0;
}
-static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
+static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta,
+ u32 curr, const bool probe_pass)
{
+ const s64 imm_min = S32_MIN, imm_max = S32_MAX;
+ s64 imm = insn->imm;
+
+ if (curr < pos && curr + imm + 1 > pos)
+ imm += delta;
+ else if (curr > pos + delta && curr + imm + 1 <= pos + delta)
+ imm -= delta;
+ if (imm < imm_min || imm > imm_max)
+ return -ERANGE;
+ if (!probe_pass)
+ insn->imm = imm;
+ return 0;
+}
+
+static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta,
+ u32 curr, const bool probe_pass)
+{
+ const s32 off_min = S16_MIN, off_max = S16_MAX;
+ s32 off = insn->off;
+
+ if (curr < pos && curr + off + 1 > pos)
+ off += delta;
+ else if (curr > pos + delta && curr + off + 1 <= pos + delta)
+ off -= delta;
+ if (off < off_min || off > off_max)
+ return -ERANGE;
+ if (!probe_pass)
+ insn->off = off;
+ return 0;
+}
+
+static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta,
+ const bool probe_pass)
+{
+ u32 i, insn_cnt = prog->len + (probe_pass ? delta : 0);
struct bpf_insn *insn = prog->insnsi;
- u32 i, insn_cnt = prog->len;
- bool pseudo_call;
- u8 code;
- int off;
+ int ret = 0;
for (i = 0; i < insn_cnt; i++, insn++) {
+ u8 code;
+
+ /* In the probing pass we still operate on the original,
+ * unpatched image in order to check overflows before we
+ * do any other adjustments. Therefore skip the patchlet.
+ */
+ if (probe_pass && i == pos) {
+ i += delta + 1;
+ insn++;
+ }
code = insn->code;
- if (BPF_CLASS(code) != BPF_JMP)
- continue;
- if (BPF_OP(code) == BPF_EXIT)
+ if (BPF_CLASS(code) != BPF_JMP ||
+ BPF_OP(code) == BPF_EXIT)
continue;
+ /* Adjust offset of jmps if we cross patch boundaries. */
if (BPF_OP(code) == BPF_CALL) {
- if (insn->src_reg == BPF_PSEUDO_CALL)
- pseudo_call = true;
- else
+ if (insn->src_reg != BPF_PSEUDO_CALL)
continue;
+ ret = bpf_adj_delta_to_imm(insn, pos, delta, i,
+ probe_pass);
} else {
- pseudo_call = false;
+ ret = bpf_adj_delta_to_off(insn, pos, delta, i,
+ probe_pass);
}
- off = pseudo_call ? insn->imm : insn->off;
-
- /* Adjust offset of jmps if we cross boundaries. */
- if (i < pos && i + off + 1 > pos)
- off += delta;
- else if (i > pos + delta && i + off + 1 <= pos + delta)
- off -= delta;
-
- if (pseudo_call)
- insn->imm = off;
- else
- insn->off = off;
+ if (ret)
+ break;
}
+
+ return ret;
}
struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
const struct bpf_insn *patch, u32 len)
{
u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
+ const u32 cnt_max = S16_MAX;
struct bpf_prog *prog_adj;
/* Since our patchlet doesn't expand the image, we're done. */
@@ -269,6 +307,15 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
insn_adj_cnt = prog->len + insn_delta;
+ /* Reject anything that would potentially let the insn->off
+ * target overflow when we have excessive program expansions.
+ * We need to probe here before we do any reallocation where
+ * we afterwards may not fail anymore.
+ */
+ if (insn_adj_cnt > cnt_max &&
+ bpf_adj_branches(prog, off, insn_delta, true))
+ return NULL;
+
/* Several new instructions need to be inserted. Make room
* for them. Likely, there's no need for a new allocation as
* last page could have large enough tailroom.
@@ -294,7 +341,11 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
sizeof(*patch) * insn_rest);
memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
- bpf_adj_branches(prog_adj, off, insn_delta);
+ /* We are guaranteed to not fail at this point, otherwise
+ * the ship has sailed to reverse to the original state. An
+ * overflow cannot happen at this point.
+ */
+ BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false));
return prog_adj;
}
@@ -633,23 +684,6 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from,
*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
break;
- case BPF_LD | BPF_ABS | BPF_W:
- case BPF_LD | BPF_ABS | BPF_H:
- case BPF_LD | BPF_ABS | BPF_B:
- *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
- *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
- *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
- break;
-
- case BPF_LD | BPF_IND | BPF_W:
- case BPF_LD | BPF_IND | BPF_H:
- case BPF_LD | BPF_IND | BPF_B:
- *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
- *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
- *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
- *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
- break;
-
case BPF_LD | BPF_IMM | BPF_DW:
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
@@ -890,14 +924,7 @@ EXPORT_SYMBOL_GPL(__bpf_call_base);
INSN_3(LDX, MEM, W), \
INSN_3(LDX, MEM, DW), \
/* Immediate based. */ \
- INSN_3(LD, IMM, DW), \
- /* Misc (old cBPF carry-over). */ \
- INSN_3(LD, ABS, B), \
- INSN_3(LD, ABS, H), \
- INSN_3(LD, ABS, W), \
- INSN_3(LD, IND, B), \
- INSN_3(LD, IND, H), \
- INSN_3(LD, IND, W)
+ INSN_3(LD, IMM, DW)
bool bpf_opcode_in_insntable(u8 code)
{
@@ -907,6 +934,13 @@ bool bpf_opcode_in_insntable(u8 code)
[0 ... 255] = false,
/* Now overwrite non-defaults ... */
BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
+ /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
+ [BPF_LD | BPF_ABS | BPF_B] = true,
+ [BPF_LD | BPF_ABS | BPF_H] = true,
+ [BPF_LD | BPF_ABS | BPF_W] = true,
+ [BPF_LD | BPF_IND | BPF_B] = true,
+ [BPF_LD | BPF_IND | BPF_H] = true,
+ [BPF_LD | BPF_IND | BPF_W] = true,
};
#undef BPF_INSN_3_TBL
#undef BPF_INSN_2_TBL
@@ -937,8 +971,6 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
#undef BPF_INSN_3_LBL
#undef BPF_INSN_2_LBL
u32 tail_call_cnt = 0;
- void *ptr;
- int off;
#define CONT ({ insn++; goto select_insn; })
#define CONT_JMP ({ insn++; goto select_insn; })
@@ -1265,67 +1297,6 @@ out:
atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
(DST + insn->off));
CONT;
- LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
- off = IMM;
-load_word:
- /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
- * appearing in the programs where ctx == skb
- * (see may_access_skb() in the verifier). All programs
- * keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
- * bpf_convert_filter() saves it in BPF_R6, internal BPF
- * verifier will check that BPF_R6 == ctx.
- *
- * BPF_ABS and BPF_IND are wrappers of function calls,
- * so they scratch BPF_R1-BPF_R5 registers, preserve
- * BPF_R6-BPF_R9, and store return value into BPF_R0.
- *
- * Implicit input:
- * ctx == skb == BPF_R6 == CTX
- *
- * Explicit input:
- * SRC == any register
- * IMM == 32-bit immediate
- *
- * Output:
- * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
- */
-
- ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
- if (likely(ptr != NULL)) {
- BPF_R0 = get_unaligned_be32(ptr);
- CONT;
- }
-
- return 0;
- LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
- off = IMM;
-load_half:
- ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
- if (likely(ptr != NULL)) {
- BPF_R0 = get_unaligned_be16(ptr);
- CONT;
- }
-
- return 0;
- LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
- off = IMM;
-load_byte:
- ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
- if (likely(ptr != NULL)) {
- BPF_R0 = *(u8 *)ptr;
- CONT;
- }
-
- return 0;
- LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
- off = IMM + SRC;
- goto load_word;
- LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
- off = IMM + SRC;
- goto load_half;
- LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
- off = IMM + SRC;
- goto load_byte;
default_label:
/* If we ever reach this, we have a bug somewhere. Die hard here
@@ -1572,13 +1543,32 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)
return cnt;
}
+static bool bpf_prog_array_copy_core(struct bpf_prog **prog,
+ u32 *prog_ids,
+ u32 request_cnt)
+{
+ int i = 0;
+
+ for (; *prog; prog++) {
+ if (*prog == &dummy_bpf_prog.prog)
+ continue;
+ prog_ids[i] = (*prog)->aux->id;
+ if (++i == request_cnt) {
+ prog++;
+ break;
+ }
+ }
+
+ return !!(*prog);
+}
+
int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
__u32 __user *prog_ids, u32 cnt)
{
struct bpf_prog **prog;
unsigned long err = 0;
- u32 i = 0, *ids;
bool nospc;
+ u32 *ids;
/* users of this function are doing:
* cnt = bpf_prog_array_length();
@@ -1595,16 +1585,7 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
return -ENOMEM;
rcu_read_lock();
prog = rcu_dereference(progs)->progs;
- for (; *prog; prog++) {
- if (*prog == &dummy_bpf_prog.prog)
- continue;
- ids[i] = (*prog)->aux->id;
- if (++i == cnt) {
- prog++;
- break;
- }
- }
- nospc = !!(*prog);
+ nospc = bpf_prog_array_copy_core(prog, ids, cnt);
rcu_read_unlock();
err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
kfree(ids);
@@ -1635,6 +1616,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
int new_prog_cnt, carry_prog_cnt = 0;
struct bpf_prog **existing_prog;
struct bpf_prog_array *array;
+ bool found_exclude = false;
int new_prog_idx = 0;
/* Figure out how many existing progs we need to carry over to
@@ -1643,14 +1625,20 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
if (old_array) {
existing_prog = old_array->progs;
for (; *existing_prog; existing_prog++) {
- if (*existing_prog != exclude_prog &&
- *existing_prog != &dummy_bpf_prog.prog)
+ if (*existing_prog == exclude_prog) {
+ found_exclude = true;
+ continue;
+ }
+ if (*existing_prog != &dummy_bpf_prog.prog)
carry_prog_cnt++;
if (*existing_prog == include_prog)
return -EEXIST;
}
}
+ if (exclude_prog && !found_exclude)
+ return -ENOENT;
+
/* How many progs (not NULL) will be in the new array? */
new_prog_cnt = carry_prog_cnt;
if (include_prog)
@@ -1683,22 +1671,25 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
}
int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
- __u32 __user *prog_ids, u32 request_cnt,
- __u32 __user *prog_cnt)
+ u32 *prog_ids, u32 request_cnt,
+ u32 *prog_cnt)
{
+ struct bpf_prog **prog;
u32 cnt = 0;
if (array)
cnt = bpf_prog_array_length(array);
- if (copy_to_user(prog_cnt, &cnt, sizeof(cnt)))
- return -EFAULT;
+ *prog_cnt = cnt;
/* return early if user requested only program count or nothing to copy */
if (!request_cnt || !cnt)
return 0;
- return bpf_prog_array_copy_to_user(array, prog_ids, request_cnt);
+ /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
+ prog = rcu_dereference_check(array, 1)->progs;
+ return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC
+ : 0;
}
static void bpf_prog_free_deferred(struct work_struct *work)
@@ -1709,6 +1700,10 @@ static void bpf_prog_free_deferred(struct work_struct *work)
aux = container_of(work, struct bpf_prog_aux, work);
if (bpf_prog_is_dev_bound(aux))
bpf_prog_offload_destroy(aux->prog);
+#ifdef CONFIG_PERF_EVENTS
+ if (aux->prog->has_callchain_buf)
+ put_callchain_buffers();
+#endif
for (i = 0; i < aux->func_cnt; i++)
bpf_jit_free(aux->func[i]);
if (aux->func_cnt) {
@@ -1769,6 +1764,8 @@ const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
const struct bpf_func_proto bpf_get_current_comm_proto __weak;
const struct bpf_func_proto bpf_sock_map_update_proto __weak;
+const struct bpf_func_proto bpf_sock_hash_update_proto __weak;
+const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
@@ -1781,6 +1778,7 @@ bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
{
return -ENOTSUPP;
}
+EXPORT_SYMBOL_GPL(bpf_event_output);
/* Always built-in helper functions. */
const struct bpf_func_proto bpf_tail_call_proto = {
@@ -1827,9 +1825,3 @@ int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
#include <linux/bpf_trace.h>
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
-
-/* These are only used within the BPF_SYSCALL code */
-#ifdef CONFIG_BPF_SYSCALL
-EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
-EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);
-#endif
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