diff options
| author | Norbert Szetei <norbert@doyensec.com> | 2026-03-25 18:26:13 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2026-03-26 18:10:58 +0900 |
| commit | 62397b493e14107ae82d8b80938f293d95425bcb (patch) | |
| tree | 113a7d09b93cdca69ff5f185fdfca99ae580cc8d | |
| parent | 6d89f743e57cb34e233a8217b394c7ee09abf225 (diff) | |
crypto: af-alg - fix NULL pointer dereference in scatterwalk
The AF_ALG interface fails to unmark the end of a Scatter/Gather List (SGL)
when chaining a new af_alg_tsgl structure. If a sendmsg() fills an SGL
exactly to MAX_SGL_ENTS, the last entry is marked as the end. A subsequent
sendmsg() allocates a new SGL and chains it, but fails to clear the end
marker on the previous SGL's last data entry.
This causes the crypto scatterwalk to hit a premature end, returning NULL
on sg_next() and leading to a kernel panic during dereference.
Fix this by explicitly unmarking the end of the previous SGL when
performing sg_chain() in af_alg_alloc_tsgl().
Fixes: 8ff590903d5f ("crypto: algif_skcipher - User-space interface for skcipher operations")
Signed-off-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | crypto/af_alg.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 0bb609fbec7d..c2fd9cd86c5e 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -623,8 +623,10 @@ static int af_alg_alloc_tsgl(struct sock *sk) sg_init_table(sgl->sg, MAX_SGL_ENTS + 1); sgl->cur = 0; - if (sg) + if (sg) { + sg_unmark_end(sg + MAX_SGL_ENTS - 1); sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg); + } list_add_tail(&sgl->list, &ctx->tsgl_list); } |