From: Aurelien Aptel <aaptel@suse.com>
Date: Mon, 4 Jun 2018 22:29:35 +0200
Subject: [PATCH] CIFS: Fix NULL ptr deref
Git-commit: 8ddecf5fd728d3c6373394fa647d28e7c27f93a7
Patch-mainline: v4.18-rc1
References: bsc#1144333
cifs->master_tlink is NULL against Win Server 2016 (which is
strange.. not sure why) and is dereferenced in cifs_sb_master_tcon().
move master_tlink getter to cifsglob.h so it can be used from
smb2misc.c
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
---
fs/cifs/cifsglob.h | 6 ++++++
fs/cifs/connect.c | 6 ------
fs/cifs/smb2misc.c | 4 +++-
3 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 08d1cdd96701..1efa2e65bc1a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1019,6 +1019,12 @@ tlink_tcon(struct tcon_link *tlink)
return tlink->tl_tcon;
}
+static inline struct tcon_link *
+cifs_sb_master_tlink(struct cifs_sb_info *cifs_sb)
+{
+ return cifs_sb->master_tlink;
+}
+
extern void cifs_put_tlink(struct tcon_link *tlink);
static inline struct tcon_link *
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index e5a2fe7f0dd4..9089b73809de 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3116,12 +3116,6 @@ cifs_put_tlink(struct tcon_link *tlink)
return;
}
-static inline struct tcon_link *
-cifs_sb_master_tlink(struct cifs_sb_info *cifs_sb)
-{
- return cifs_sb->master_tlink;
-}
-
static int
compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
{
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index cb5728e3d87d..e2bec47c6845 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -453,8 +453,10 @@ cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
start_of_path = from + 1;
#ifdef CONFIG_CIFS_SMB311
/* SMB311 POSIX extensions paths do not include leading slash */
- else if (cifs_sb_master_tcon(cifs_sb)->posix_extensions)
+ else if (cifs_sb_master_tlink(cifs_sb) &&
+ cifs_sb_master_tcon(cifs_sb)->posix_extensions) {
start_of_path = from + 1;
+ }
#endif /* 311 */
else
start_of_path = from;
--
2.16.4