From 8824b7af409f51f1316e92e9887c2fd48c0b26d6 Mon Sep 17 00:00:00 2001 From: William Liu Date: Fri, 30 Dec 2022 09:13:35 +0900 Subject: ksmbd: check nt_len to be at least CIFS_ENCPWD_SIZE in ksmbd_decode_ntlmssp_auth_blob MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit "nt_len - CIFS_ENCPWD_SIZE" is passed directly from ksmbd_decode_ntlmssp_auth_blob to ksmbd_auth_ntlmv2. Malicious requests can set nt_len to less than CIFS_ENCPWD_SIZE, which results in a negative number (or large unsigned value) used for a subsequent memcpy in ksmbd_auth_ntlvm2 and can cause a panic. Fixes: e2f3448 ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Signed-off-by: William Liu Signed-off-by: Hrvoje Mišetić Signed-off-by: Namjae Jeon --- auth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/auth.c +++ b/auth.c @@ -583,7 +583,8 @@ int ksmbd_decode_ntlmssp_auth_blob(struc dn_off = le32_to_cpu(authblob->DomainName.BufferOffset); dn_len = le16_to_cpu(authblob->DomainName.Length); - if (blob_len < (u64)dn_off + dn_len || blob_len < (u64)nt_off + nt_len) + if (blob_len < (u64)dn_off + dn_len || blob_len < (u64)nt_off + nt_len || + nt_len < CIFS_ENCPWD_SIZE) return -EINVAL; #ifdef CONFIG_SMB_INSECURE_SERVER