diff options
| author | Florian Westphal <fw@strlen.de> | 2023-12-21 11:25:14 +0100 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2023-12-22 11:57:46 +0100 |
| commit | dcb199544563ded462cb7151134278f82a9e6cfd (patch) | |
| tree | b1a1937e32bf5eda4126fb288751fdddb9fbda42 /include/expression.h | |
| parent | b9e19cc396347df8c7f8cf5d14ba1d6172040f16 (diff) | |
src: do not allow to chain more than 16 binops
netlink_linearize.c has never supported more than 16 chained binops.
Adding more is possible but overwrites the stack in
netlink_gen_bitwise().
Add a recursion counter to catch this at eval stage.
Its not enough to just abort once the counter hits
NFT_MAX_EXPR_RECURSION.
This is because there are valid test cases that exceed this.
For example, evaluation of 1 | 2 will merge the constans, so even
if there are a dozen recursive eval calls this will not end up
with large binop chain post-evaluation.
v2: allow more than 16 binops iff the evaluation function
did constant-merging.
Signed-off-by: Florian Westphal <fw@strlen.de>
Diffstat (limited to 'include/expression.h')
| -rw-r--r-- | include/expression.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/expression.h b/include/expression.h index 809089c8..f5d7e160 100644 --- a/include/expression.h +++ b/include/expression.h @@ -13,6 +13,7 @@ #define NFT_MAX_EXPR_LEN_BYTES (NFT_REG32_COUNT * sizeof(uint32_t)) #define NFT_MAX_EXPR_LEN_BITS (NFT_MAX_EXPR_LEN_BYTES * BITS_PER_BYTE) +#define NFT_MAX_EXPR_RECURSION 16 /** * enum expr_types |