From: Herbert Xu Date: Thu, 30 Apr 2026 06:36:03 +0000 (-0700) Subject: crypto: af_alg - Fix page reassignment overflow in af_alg_pull_tsgl X-Git-Tag: v5.15.204~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2b781d1d4f933990318bcc5c68fb75a717379e42;p=thirdparty%2Fkernel%2Fstable.git crypto: af_alg - Fix page reassignment overflow in af_alg_pull_tsgl 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 Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 4f667a503277..8f7cf57da8f6 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -597,8 +597,8 @@ 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++;