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ksmbd: check nt_len to be at least CIFS_ENCPWD_SIZE in ksmbd_decode_ntlmssp_auth_blob

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commit 797805d81baa814f76cf7bdab35f86408a79d707 upstream.

"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: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: William Liu <will@willsroot.io>
Signed-off-by: Hrvoje Mišetić <misetichrvoje@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
William Liu 2022-12-30 13:03:15 +09:00 committed by Greg Kroah-Hartman
parent 4136f1ac1e
commit e32f867b37
1 changed files with 2 additions and 1 deletions
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3
fs/ksmbd/auth.c
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@ -319,7 +319,8 @@ int ksmbd_decode_ntlmssp_auth_blob(struct authenticate_message *authblob,
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;
/* TODO : use domain name that imported from configuration file */