4.9-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 68e2672f8fbd1e04982b8d2798dd318bf2515dd2 ]
There is a NULL pointer dereference of devname in strspn()
The oops looks something like:
CIFS: Attempting to mount (null) BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... RIP: 0010:strspn+0x0/0x50 ... Call Trace: ? cifs_parse_mount_options+0x222/0x1710 [cifs] ? cifs_get_volume_info+0x2f/0x80 [cifs] cifs_setup_volume_info+0x20/0x190 [cifs] cifs_get_volume_info+0x50/0x80 [cifs] cifs_smb3_do_mount+0x59/0x630 [cifs] ? ida_alloc_range+0x34b/0x3d0 cifs_do_mount+0x11/0x20 [cifs] mount_fs+0x52/0x170 vfs_kern_mount+0x6b/0x170 do_mount+0x216/0xdc0 ksys_mount+0x83/0xd0 __x64_sys_mount+0x25/0x30 do_syscall_64+0x65/0x220 entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix this by adding a NULL check on devname in cifs_parse_devname()
Signed-off-by: Yao Liu yotta.liu@ucloud.cn Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/connect.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 33e65b71c49a..f291ed0c155d 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -1201,6 +1201,11 @@ cifs_parse_devname(const char *devname, struct smb_vol *vol) const char *delims = "/\"; size_t len;
+ if (unlikely(!devname || !*devname)) { + cifs_dbg(VFS, "Device name not specified.\n"); + return -EINVAL; + } + /* make sure we have a valid UNC double delimiter prefix */ len = strspn(devname, delims); if (len != 2)