Before:
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 }
^^^^^^^^^
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
Pablo, I can merge this with
"[nft] parser_bison: reject large raw payload expressions" if you
prefer.
src/evaluate.c | 4 ++++
.../bogons/nft-f/stack_overflow_via_large_concat_expr | 5 +++++
2 files changed, 9 insertions(+)
create mode 100644 tests/shell/testcases/bogons/nft-f/stack_overflow_via_large_concat_expr
diff --git a/src/evaluate.c b/src/evaluate.c
index c7191e8cad08..e2d9a320587e 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_REG32_COUNT * sizeof(uint32_t) * BITS_PER_BYTE)
+ return expr_error(ctx->msgs, i, "Concatenation of size %u exceeds maximum size of %u",
+ size, NFT_REG32_COUNT * sizeof(uint32_t) * BITS_PER_BYTE);
}
(*expr)->flags |= flags;
diff --git a/tests/shell/testcases/bogons/nft-f/stack_overflow_via_large_concat_expr b/tests/shell/testcases/bogons/nft-f/stack_overflow_via_large_concat_expr
new file mode 100644
index 000000000000..8b0d27444c22
--- /dev/null
+++ b/tests/shell/testcases/bogons/nft-f/stack_overflow_via_large_concat_expr
@@ -0,0 +1,5 @@
+table t {
+ chain c {
+ udp length . @th,0,512 . @th,512,512 { 47-63 . 0xe373135363130 . 0x33131303735353203 }
+ }
+}
--
2.41.0
