cifs: fix NULL dereference in match_prepath

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 <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Ronnie Sahlberg 2020-01-22 11:07:56 +10:00 committed by Steve French
parent 643fbceef4
commit fe12926863

View File

@ -3709,8 +3709,10 @@ match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
{ {
struct cifs_sb_info *old = CIFS_SB(sb); struct cifs_sb_info *old = CIFS_SB(sb);
struct cifs_sb_info *new = mnt_data->cifs_sb; struct cifs_sb_info *new = mnt_data->cifs_sb;
bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH; bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
bool new_set = new->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)) if (old_set && new_set && !strcmp(new->prepath, old->prepath))
return 1; return 1;