kernel/SOURCES/1178-crypto-af-alg-fix-null-pointer-dereference-in-scatterwalk.patch
Andrew Lukoshko 5c58271075 Recreate RHEL 5.14.0-687.10.1 from CS9/upstream backports
Drop the 687.5.3/687.5.4 security-ahead patches superseded by the RHEL
687.6.1..687.10.1 backports (1100-1104), and add those backports (1100-1196)
sourced from centos-stream-9 and upstream stable. Keep the AlmaLinux-ahead
smb cifs.spnego fix (retained as 1197). Bump to 5.14.0-687.10.1.
2026-06-06 22:36:55 +00:00

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From 00de3c031466400b8db061ae3149de8c64999974 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert.xu@redhat.com>
Date: Thu, 30 Apr 2026 12:54:18 +0800
Subject: [PATCH] crypto: af-alg - fix NULL pointer dereference in scatterwalk
JIRA: https://redhat.atlassian.net/browse/RHEL-172207
Upstream Status: 62397b493e14107ae82d8b80938f293d95425bcb
commit 62397b493e14107ae82d8b80938f293d95425bcb
Author: Norbert Szetei <norbert@doyensec.com>
Date: Wed Mar 25 18:26:13 2026 +0100
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>
Signed-off-by: Herbert Xu <herbert.xu@redhat.com>
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 67e66729281b..25d9d907dd9f 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -513,8 +513,10 @@ 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);
}
--
2.50.1 (Apple Git-155)