From: Paulo Alcantara Date: Fri, 25 Jul 2025 03:04:43 +0000 (-0300) Subject: smb: client: allow parsing zero-length AV pairs X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be77ab6b9fbe348daf3c2d3ee40f23ca5110a339;p=thirdparty%2Fkernel%2Flinux.git smb: client: allow parsing zero-length AV pairs Zero-length AV pairs should be considered as valid target infos. Don't skip the next AV pairs that follow them. Cc: linux-cifs@vger.kernel.org Cc: David Howells Fixes: 0e8ae9b953bc ("smb: client: parse av pair type 4 in CHALLENGE_MESSAGE") Signed-off-by: Paulo Alcantara (Red Hat) Signed-off-by: Steve French --- diff --git a/fs/smb/client/cifsencrypt.c b/fs/smb/client/cifsencrypt.c index 35892df7335c7..6be850d2a3467 100644 --- a/fs/smb/client/cifsencrypt.c +++ b/fs/smb/client/cifsencrypt.c @@ -343,7 +343,7 @@ static struct ntlmssp2_name *find_next_av(struct cifs_ses *ses, len = AV_LEN(av); if (AV_TYPE(av) == NTLMSSP_AV_EOL) return NULL; - if (!len || (u8 *)av + sizeof(*av) + len > end) + if ((u8 *)av + sizeof(*av) + len > end) return NULL; return av; } @@ -363,7 +363,7 @@ static int find_av_name(struct cifs_ses *ses, u16 type, char **name, u16 maxlen) av_for_each_entry(ses, av) { len = AV_LEN(av); - if (AV_TYPE(av) != type) + if (AV_TYPE(av) != type || !len) continue; if (!IS_ALIGNED(len, sizeof(__le16))) { cifs_dbg(VFS | ONCE, "%s: bad length(%u) for type %u\n",