[PATCH 6.6 072/102] smb: client: fix NULL ptr deref in cifs_mark_open_handles_for_deleted_file()

Greg Kroah-Hartman
2024-05-23T13:25:43Z

From: Paulo Alcantara <pc@manguebit.com>

[ Upstream commit ec4535b2a1d709d3a1fbec26739c672f13c98a7b ]

cifs_get_fattr() may be called with a NULL inode, so check for a
non-NULL inode before calling
cifs_mark_open_handles_for_deleted_file().

This fixes the following oops:

mount.cifs //srv/share /mnt -o ...,vers=3.1.1
cd /mnt
touch foo; tail -f foo &
rm foo
cat foo

BUG: kernel NULL pointer dereference, address: 00000000000005c0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 2 PID: 696 Comm: cat Not tainted 6.9.0-rc2 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.16.3-1.fc39 04/01/2014
RIP: 0010:__lock_acquire+0x5d/0x1c70
Code: 00 00 44 8b a4 24 a0 00 00 00 45 85 f6 0f 84 bb 06 00 00 8b 2d
48 e2 95 01 45 89 c3 41 89 d2 45 89 c8 85 ed 0 0 <48> 81 3f 40 7a 76
83 44 0f 44 d8 83 fe 01 0f 86 1b 03 00 00 31 d2
RSP: 0018:ffffc90000b37490 EFLAGS: 00010002
RAX: 0000000000000000 RBX: ffff888110021ec0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000005c0
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000200
FS: 00007f2a1fa08740(0000) GS:ffff888157a00000(0000)
knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2: 00000000000005c0 CR3: 000000011ac7c000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
<TASK>
? __die+0x23/0x70
? page_fault_oops+0x180/0x490
? srso_alias_return_thunk+0x5/0xfbef5
? exc_page_fault+0x70/0x230
? asm_exc_page_fault+0x26/0x30
? __lock_acquire+0x5d/0x1c70
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
lock_acquire+0xc0/0x2d0
? cifs_mark_open_handles_for_deleted_file+0x3a/0x100 [cifs]
? srso_alias_return_thunk+0x5/0xfbef5
? kmem_cache_alloc+0x2d9/0x370
_raw_spin_lock+0x34/0x80
? cifs_mark_open_handles_for_deleted_file+0x3a/0x100 [cifs]
cifs_mark_open_handles_for_deleted_file+0x3a/0x100 [cifs]
cifs_get_fattr+0x24c/0x940 [cifs]
? srso_alias_return_thunk+0x5/0xfbef5
cifs_get_inode_info+0x96/0x120 [cifs]
cifs_lookup+0x16e/0x800 [cifs]
cifs_atomic_open+0xc7/0x5d0 [cifs]
? lookup_open.isra.0+0x3ce/0x5f0
? __pfx_cifs_atomic_open+0x10/0x10 [cifs]
lookup_open.isra.0+0x3ce/0x5f0
path_openat+0x42b/0xc30
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
do_filp_open+0xc4/0x170
do_sys_openat2+0xab/0xe0
__x64_sys_openat+0x57/0xa0
do_syscall_64+0xc1/0x1e0
entry_SYSCALL_64_after_hwframe+0x72/0x7a

Fixes: ffceb7640cbf ("smb: client: do not defer close open handles to deleted files")
Reviewed-by: Meetakshi Setiya <msetiya@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/client/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index b304215a4d668..9cdbc3ccc1d14 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1105,7 +1105,8 @@ static int cifs_get_fattr(struct cifs_open_info_data *data,
} else {
cifs_open_info_to_fattr(fattr, data, sb);
}
- if (!rc && fattr->cf_flags & CIFS_FATTR_DELETE_PENDING)
+ if (!rc && *inode &&
+ (fattr->cf_flags & CIFS_FATTR_DELETE_PENDING))
cifs_mark_open_handles_for_deleted_file(*inode, full_path);
break;
case -EREMOTE:
--
2.43.0