From: Herbert Xu <herbert@gondor.apana.org.au> stable inclusion from stable-v5.10.254 commit fa48d3ea9cdbfb28c1fd6756c6c5cd01351aa51e category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14174 CVE: CVE-2026-31431 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 31d00156e50ecad37f2cb6cbf04aaa9a260505ef upstream. When page reassignment was added to af_alg_pull_tsgl the original loop wasn't updated so it may try to reassign one more page than necessary. Add the check to the reassignment so that this does not happen. Also update the comment which still refers to the obsolete offset argument. Reported-by: syzbot+d23888375c2737c17ba5@syzkaller.appspotmail.com Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tengda Wu <wutengda2@huawei.com> --- crypto/af_alg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 680c49d83fde..30c08315d233 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -595,8 +595,8 @@ void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst) * Assumption: caller created af_alg_count_tsgl(len) * SG entries in dst. */ - if (dst) { - /* reassign page to dst after offset */ + if (dst && plen) { + /* reassign page to dst */ get_page(page); sg_set_page(dst + j, page, plen, sg[i].offset); j++; -- 2.34.1