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ksmbd: fix out-of-bound read in smb2_write

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ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If
->NextCommand is bigger than Offset + Length of smb2 write, It will
allow oversized smb2 write length. It will cause OOB read in smb2_write.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21164
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Namjae Jeon 2023-06-15 22:04:40 +09:00 committed by Steve French
parent 40b268d384
commit 5fe7f7b782
1 changed files with 9 additions and 3 deletions
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12
fs/smb/server/smb2misc.c
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@ -351,10 +351,16 @@ 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;
__u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand);
if (le32_to_cpu(hdr->NextCommand) > 0)
len = le32_to_cpu(hdr->NextCommand);
if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) {
pr_err("next command(%u) offset exceeds smb msg size\n",
next_cmd);
return 1;
}
if (next_cmd > 0)
len = next_cmd;
else if (work->next_smb2_rcv_hdr_off)
len -= work->next_smb2_rcv_hdr_off;