[PATCH 4.9 100/165] cifs: fix NULL dereference in match_prepath
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2020-02-27 13:49:17
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Ronnie Sahlberg <redacted> [ Upstream commit fe1292686333d1dadaf84091f585ee903b9ddb84 ] RHBZ: 1760879 Fix an oops in match_prepath() by making sure that the prepath string is not NULL before we pass it into strcmp(). This is similar to other checks we make for example in cifs_root_iget() Signed-off-by: Ronnie Sahlberg <redacted> Signed-off-by: Steve French <redacted> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/cifs/connect.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 751bdde6515d5..961fcb40183a4 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c@@ -2927,8 +2927,10 @@ match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data) { struct cifs_sb_info *old = CIFS_SB(sb); struct cifs_sb_info *new = mnt_data->cifs_sb; - bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH; - bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH; + bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) && + old->prepath; + bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) && + new->prepath; if (old_set && new_set && !strcmp(new->prepath, old->prepath)) return 1;
--
2.20.1