diff mbox series

ksmb: discard write access to the directory open

Message ID 20240704003537.4690-1-hobin.woo@samsung.com
State New
Headers show
Series ksmb: discard write access to the directory open | expand

Commit Message

Hobin Woo July 4, 2024, 12:35 a.m. UTC 
may_open() does not allow a directory to be opened with the write access.
However, some writing flags set by client result in adding write access
on server, making ksmbd incompatible with FUSE file system. Simply, let's
discard the write access when opening a directory.

list_add corruption. next is NULL.
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:26!
pc : __list_add_valid+0x88/0xbc
lr : __list_add_valid+0x88/0xbc
Call trace:
__list_add_valid+0x88/0xbc
fuse_finish_open+0x11c/0x170
fuse_open_common+0x284/0x5e8
fuse_dir_open+0x14/0x24
do_dentry_open+0x2a4/0x4e0
dentry_open+0x50/0x80
smb2_open+0xbe4/0x15a4
handle_ksmbd_work+0x478/0x5ec
process_one_work+0x1b4/0x448
worker_thread+0x25c/0x430
kthread+0x104/0x1d4
ret_from_fork+0x10/0x20

Signed-off-by: Yoonho Shin <yoonho.shin@samsung.com>
Signed-off-by: Hobin Woo <hobin.woo@samsung.com>
---
 fs/smb/server/smb2pdu.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Comments

Namjae Jeon July 4, 2024, 2:40 a.m. UTC | #1 
2024년 7월 4일 (목) 오전 9:35, Hobin Woo <hobin.woo@samsung.com>님이 작성:
>
> may_open() does not allow a directory to be opened with the write access.
> However, some writing flags set by client result in adding write access
> on server, making ksmbd incompatible with FUSE file system. Simply, let's
> discard the write access when opening a directory.
>
> list_add corruption. next is NULL.
> ------------[ cut here ]------------
> kernel BUG at lib/list_debug.c:26!
> pc : __list_add_valid+0x88/0xbc
> lr : __list_add_valid+0x88/0xbc
> Call trace:
> __list_add_valid+0x88/0xbc
> fuse_finish_open+0x11c/0x170
> fuse_open_common+0x284/0x5e8
> fuse_dir_open+0x14/0x24
> do_dentry_open+0x2a4/0x4e0
> dentry_open+0x50/0x80
> smb2_open+0xbe4/0x15a4
> handle_ksmbd_work+0x478/0x5ec
> process_one_work+0x1b4/0x448
> worker_thread+0x25c/0x430
> kthread+0x104/0x1d4
> ret_from_fork+0x10/0x20
>
> Signed-off-by: Yoonho Shin <yoonho.shin@samsung.com>
> Signed-off-by: Hobin Woo <hobin.woo@samsung.com>
Applied it to #ksmbd-for-next-next.
Thanks for your patch!
diff mbox series

Patch

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index e7e07891781b..bebfa5f6d82e 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2056,10 +2056,16 @@  int smb2_tree_connect(struct ksmbd_work *work)
  */
 static int smb2_create_open_flags(bool file_present, __le32 access,
 				  __le32 disposition,
-				  int *may_flags)
+				  int *may_flags,
+				  bool is_dir)
 {
 	int oflags = O_NONBLOCK | O_LARGEFILE;
 
+	if (is_dir) {
+		access &= ~FILE_WRITE_DESIRE_ACCESS_LE;
+		ksmbd_debug(SMB, "Discard write access to a directory\n");
+	}
+
 	if (access & FILE_READ_DESIRED_ACCESS_LE &&
 	    access & FILE_WRITE_DESIRE_ACCESS_LE) {
 		oflags |= O_RDWR;
@@ -3167,7 +3173,9 @@  int smb2_open(struct ksmbd_work *work)
 
 	open_flags = smb2_create_open_flags(file_present, daccess,
 					    req->CreateDisposition,
-					    &may_flags);
+					    &may_flags,
+		req->CreateOptions & FILE_DIRECTORY_FILE_LE ||
+		(file_present && S_ISDIR(d_inode(path.dentry)->i_mode)));
 
 	if (!test_tree_conn_flag(tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {
 		if (open_flags & (O_CREAT | O_TRUNC)) {