commit 2b9b8f3b68edb3d67d79962f02e26dbb5ae3808d upstream.
->StructureSize2 indicates command payload size. ksmbd should validate this size with rfc1002 length before accessing it. This patch remove unneeded check and add the validation for this.
[ 8.912583] BUG: KASAN: slab-out-of-bounds in ksmbd_smb2_check_message+0x12a/0xc50 [ 8.913051] Read of size 2 at addr ffff88800ac7d92c by task kworker/0:0/7 ... [ 8.914967] Call Trace: [ 8.915126] <TASK> [ 8.915267] dump_stack_lvl+0x33/0x50 [ 8.915506] print_report+0xcc/0x620 [ 8.916558] kasan_report+0xae/0xe0 [ 8.917080] kasan_check_range+0x35/0x1b0 [ 8.917334] ksmbd_smb2_check_message+0x12a/0xc50 [ 8.917935] ksmbd_verify_smb_message+0xae/0xd0 [ 8.918223] handle_ksmbd_work+0x192/0x820 [ 8.918478] process_one_work+0x419/0x760 [ 8.918727] worker_thread+0x2a2/0x6f0 [ 8.919222] kthread+0x187/0x1d0 [ 8.919723] ret_from_fork+0x1f/0x30 [ 8.919954] </TASK>
Cc: stable@vger.kernel.org Reported-by: Chih-Yen Chang cc85nod@gmail.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/ksmbd/smb2misc.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c index abc18af14f04..ad805b37b81d 100644 --- a/fs/ksmbd/smb2misc.c +++ b/fs/ksmbd/smb2misc.c @@ -352,6 +352,7 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work) int command; __u32 clc_len; /* calculated length */ __u32 len = get_rfc1002_len(work->request_buf); + __u32 req_struct_size;
if (le32_to_cpu(hdr->NextCommand) > 0) len = le32_to_cpu(hdr->NextCommand); @@ -374,17 +375,9 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work) }
if (smb2_req_struct_sizes[command] != pdu->StructureSize2) { - if (command != SMB2_OPLOCK_BREAK_HE && - (hdr->Status == 0 || pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2_LE)) { - /* error packets have 9 byte structure size */ - ksmbd_debug(SMB, - "Illegal request size %u for command %d\n", - le16_to_cpu(pdu->StructureSize2), command); - return 1; - } else if (command == SMB2_OPLOCK_BREAK_HE && - hdr->Status == 0 && - le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_20 && - le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_21) { + if (command == SMB2_OPLOCK_BREAK_HE && + le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_20 && + le16_to_cpu(pdu->StructureSize2) != OP_BREAK_STRUCT_SIZE_21) { /* special case for SMB2.1 lease break message */ ksmbd_debug(SMB, "Illegal request size %d for oplock break\n", @@ -393,6 +386,14 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work) } }
+ req_struct_size = le16_to_cpu(pdu->StructureSize2) + + __SMB2_HEADER_STRUCTURE_SIZE; + if (command == SMB2_LOCK_HE) + req_struct_size -= sizeof(struct smb2_lock_element); + + if (req_struct_size > len + 1) + return 1; + if (smb2_calc_size(hdr, &clc_len)) return 1;