The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Thanks, Sasha
------------------ original commit in Linus's tree ------------------
From d10c77873ba1e9e6b91905018e29e196fd5f863d Mon Sep 17 00:00:00 2001 From: Namjae Jeon linkinjeon@kernel.org Date: Wed, 20 Dec 2023 15:52:11 +0900 Subject: [PATCH] ksmbd: fix slab-out-of-bounds in smb_strndup_from_utf16()
If ->NameOffset/Length is bigger than ->CreateContextsOffset/Length, ksmbd_check_message doesn't validate request buffer it correctly. So slab-out-of-bounds warning from calling smb_strndup_from_utf16() in smb2_open() could happen. If ->NameLength is non-zero, Set the larger of the two sums (Name and CreateContext size) as the offset and length of the data area.
Reported-by: Yang Chaoming lometsj@live.com Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/smb/server/smb2misc.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/fs/smb/server/smb2misc.c b/fs/smb/server/smb2misc.c index 23bd3d1209dfa..03dded29a9804 100644 --- a/fs/smb/server/smb2misc.c +++ b/fs/smb/server/smb2misc.c @@ -106,16 +106,25 @@ static int smb2_get_data_area_len(unsigned int *off, unsigned int *len, break; case SMB2_CREATE: { + unsigned short int name_off = + le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset); + unsigned short int name_len = + le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength); + if (((struct smb2_create_req *)hdr)->CreateContextsLength) { *off = le32_to_cpu(((struct smb2_create_req *) hdr)->CreateContextsOffset); *len = le32_to_cpu(((struct smb2_create_req *) hdr)->CreateContextsLength); - break; + if (!name_len) + break; + + if (name_off + name_len < (u64)*off + *len) + break; }
- *off = le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset); - *len = le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength); + *off = name_off; + *len = name_len; break; } case SMB2_QUERY_INFO: