Asim Viladi Oglu Manizada 075ea208c6 ksmbd: fix OOB write in QUERY_INFO for compound requests
commit fda9522ed6 upstream.

When a compound request such as READ + QUERY_INFO(Security) is received,
and the first command (READ) consumes most of the response buffer,
ksmbd could write beyond the allocated buffer while building a security
descriptor.

The root cause was that smb2_get_info_sec() checked buffer space using
ppntsd_size from xattr, while build_sec_desc() often synthesized a
significantly larger descriptor from POSIX ACLs.

This patch introduces smb_acl_sec_desc_scratch_len() to accurately
compute the final descriptor size beforehand, performs proper buffer
checking with smb2_calc_max_out_buf_len(), and uses exact-sized
allocation + iov pinning.

Cc: stable@vger.kernel.org
Fixes: e2b76ab8b5 ("ksmbd: add support for read compound")
Signed-off-by: Asim Viladi Oglu Manizada <manizada@pm.me>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-11 14:26:35 +02:00
…
…
2026-04-02 13:23:33 +02:00
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