4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 80ff00172407e0aad4b10b94ef0816fc3e7813cb ]
There is a NULL pointer dereference of dev_name in nfs_parse_devname()
The oops looks something like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... RIP: 0010:nfs_fs_mount+0x3b6/0xc20 [nfs] ... Call Trace: ? ida_alloc_range+0x34b/0x3d0 ? nfs_clone_super+0x80/0x80 [nfs] ? nfs_free_parsed_mount_data+0x60/0x60 [nfs] mount_fs+0x52/0x170 ? __init_waitqueue_head+0x3b/0x50 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 dev_name
Signed-off-by: Yao Liu yotta.liu@ucloud.cn Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/super.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 412fcfbc50e2..9b42139a479b 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -1877,6 +1877,11 @@ static int nfs_parse_devname(const char *dev_name, size_t len; char *end;
+ if (unlikely(!dev_name || !*dev_name)) { + dfprintk(MOUNT, "NFS: device name not specified\n"); + return -EINVAL; + } + /* Is the host name protected with square brakcets? */ if (*dev_name == '[') { end = strchr(++dev_name, ']');