diff options
| author | Florian Westphal <fw@strlen.de> | 2023-12-12 19:13:14 +0100 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2023-12-15 02:27:14 +0100 |
| commit | ef10d65db278d77208e960d210a1f4f532ebb552 (patch) | |
| tree | 354f10077f748e440f15b205071610c7c1f273b3 /src/evaluate.c | |
| parent | 8eeedce89d8bf0ad58da398782c2ca8a91d83a32 (diff) | |
src: reject large raw payload and concat expressions
The kernel will reject this too, but unfortunately nft may try
to cram the data into the underlying libnftnl expr.
This causes heap corruption or
BUG: nld buffer overflow: want to copy 132, max 64
After:
Error: Concatenation of size 544 exceeds maximum size of 512
udp length . @th,0,512 . @th,512,512 { 47-63 . 0xe373135363130 . 0x33131303735353203 }
^^^^^^^^^
resp. same warning for an over-sized raw expression.
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'src/evaluate.c')
| -rw-r--r-- | src/evaluate.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/evaluate.c b/src/evaluate.c index 1c5078d6..87cd68d3 100644 --- a/src/evaluate.c +++ b/src/evaluate.c @@ -1591,6 +1591,10 @@ static int expr_evaluate_concat(struct eval_ctx *ctx, struct expr **expr) } ctx->inner_desc = NULL; + + if (size > NFT_MAX_EXPR_LEN_BITS) + return expr_error(ctx->msgs, i, "Concatenation of size %u exceeds maximum size of %u", + size, NFT_MAX_EXPR_LEN_BITS); } (*expr)->flags |= flags; @@ -4719,6 +4723,10 @@ static int set_expr_evaluate_concat(struct eval_ctx *ctx, struct expr **expr) (*expr)->field_len[(*expr)->field_count++] = dsize_bytes; size += netlink_padded_len(i->len); + + if (size > NFT_MAX_EXPR_LEN_BITS) + return expr_error(ctx->msgs, i, "Concatenation of size %u exceeds maximum size of %u", + size, NFT_MAX_EXPR_LEN_BITS); } (*expr)->flags |= flags; |