From: Chih-Yen Chang cc85nod@gmail.com
commit f0a96d1aafd8964e1f9955c830a3e5cb3c60a90f upstream.
The offset of UserName is related to the address of security buffer. To ensure the validaty of UserName, we need to compare name_off + name_len with secbuf_len instead of auth_msg_len.
[ 27.096243] ================================================================== [ 27.096890] BUG: KASAN: slab-out-of-bounds in smb_strndup_from_utf16+0x188/0x350 [ 27.097609] Read of size 2 at addr ffff888005e3b542 by task kworker/0:0/7 ... [ 27.099950] Call Trace: [ 27.100194] <TASK> [ 27.100397] dump_stack_lvl+0x33/0x50 [ 27.100752] print_report+0xcc/0x620 [ 27.102305] kasan_report+0xae/0xe0 [ 27.103072] kasan_check_range+0x35/0x1b0 [ 27.103757] smb_strndup_from_utf16+0x188/0x350 [ 27.105474] smb2_sess_setup+0xaf8/0x19c0 [ 27.107935] handle_ksmbd_work+0x274/0x810 [ 27.108315] process_one_work+0x419/0x760 [ 27.108689] worker_thread+0x2a2/0x6f0 [ 27.109385] kthread+0x160/0x190 [ 27.110129] ret_from_fork+0x1f/0x30 [ 27.110454] </TASK>
Cc: stable@vger.kernel.org Signed-off-by: Chih-Yen Chang cc85nod@gmail.com Acked-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ksmbd/smb2pdu.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -1384,7 +1384,7 @@ static struct ksmbd_user *session_user(s struct authenticate_message *authblob; struct ksmbd_user *user; char *name; - unsigned int auth_msg_len, name_off, name_len, secbuf_len; + unsigned int name_off, name_len, secbuf_len;
secbuf_len = le16_to_cpu(req->SecurityBufferLength); if (secbuf_len < sizeof(struct authenticate_message)) { @@ -1394,9 +1394,8 @@ static struct ksmbd_user *session_user(s authblob = user_authblob(conn, req); name_off = le32_to_cpu(authblob->UserName.BufferOffset); name_len = le16_to_cpu(authblob->UserName.Length); - auth_msg_len = le16_to_cpu(req->SecurityBufferOffset) + secbuf_len;
- if (auth_msg_len < (u64)name_off + name_len) + if (secbuf_len < (u64)name_off + name_len) return NULL;
name = smb_strndup_from_utf16((const char *)authblob + name_off,