summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--kernel/bpf/core.c100
-rw-r--r--kernel/bpf/sockmap.c18
-rw-r--r--net/core/filter.c11
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c5
4 files changed, 98 insertions, 36 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ba03ec39efb3..6ef6746a7871 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -218,47 +218,84 @@ 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 +306,15 @@ 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 +340,11 @@ 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;
}
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 098eca568c2b..95a84b2f10ce 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -1703,11 +1703,11 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops,
* we increment the refcnt. If this is the case abort with an
* error.
*/
- verdict = bpf_prog_inc_not_zero(stab->bpf_verdict);
+ verdict = bpf_prog_inc_not_zero(verdict);
if (IS_ERR(verdict))
return PTR_ERR(verdict);
- parse = bpf_prog_inc_not_zero(stab->bpf_parse);
+ parse = bpf_prog_inc_not_zero(parse);
if (IS_ERR(parse)) {
bpf_prog_put(verdict);
return PTR_ERR(parse);
@@ -1715,12 +1715,12 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops,
}
if (tx_msg) {
- tx_msg = bpf_prog_inc_not_zero(stab->bpf_tx_msg);
+ tx_msg = bpf_prog_inc_not_zero(tx_msg);
if (IS_ERR(tx_msg)) {
- if (verdict)
- bpf_prog_put(verdict);
- if (parse)
+ if (parse && verdict) {
bpf_prog_put(parse);
+ bpf_prog_put(verdict);
+ }
return PTR_ERR(tx_msg);
}
}
@@ -1805,10 +1805,10 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops,
out_free:
smap_release_sock(psock, sock);
out_progs:
- if (verdict)
- bpf_prog_put(verdict);
- if (parse)
+ if (parse && verdict) {
bpf_prog_put(parse);
+ bpf_prog_put(verdict);
+ }
if (tx_msg)
bpf_prog_put(tx_msg);
write_unlock_bh(&sock->sk_callback_lock);
diff --git a/net/core/filter.c b/net/core/filter.c
index e77c30ca491d..201ff36b17a8 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -481,11 +481,18 @@ do_pass:
#define BPF_EMIT_JMP \
do { \
+ const s32 off_min = S16_MIN, off_max = S16_MAX; \
+ s32 off; \
+ \
if (target >= len || target < 0) \
goto err; \
- insn->off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
+ off = addrs ? addrs[target] - addrs[i] - 1 : 0; \
/* Adjust pc relative offset for 2nd or 3rd insn. */ \
- insn->off -= insn - tmp_insns; \
+ off -= insn - tmp_insns; \
+ /* Reject anything not fitting into insn->off. */ \
+ if (off < off_min || off > off_max) \
+ goto err; \
+ insn->off = off; \
} while (0)
case BPF_JMP | BPF_JA:
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 3e7718b1a9ae..fd7de7eb329e 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -11713,6 +11713,11 @@ static void get_unpriv_disabled()
FILE *fd;
fd = fopen("/proc/sys/"UNPRIV_SYSCTL, "r");
+ if (!fd) {
+ perror("fopen /proc/sys/"UNPRIV_SYSCTL);
+ unpriv_disabled = true;
+ return;
+ }
if (fgets(buf, 2, fd) == buf && atoi(buf))
unpriv_disabled = true;
fclose(fd);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 04:13:45 +0000