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smb3.1.1: print warning if server does not support requested encryption type 

If server does not support AES-256-GCM and it was required on mount, print
warning message. Also log and return a different error message (EOPNOTSUPP)
when encryption mechanism is not supported vs the case when an unknown
unrequested encryption mechanism could be returned (EINVAL).

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
zero-sugar-mainline-defconfig
Steve French 2020-10-15 00:14:47 -05:00
parent 29e2792304
commit 511ac89e59
1 changed files with 13 additions and 2 deletions
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15
fs/cifs/smb2pdu.c
View File

@ -610,8 +610,19 @@ static int decode_encrypt_ctx(struct TCP_Server_Info *server,
return -EINVAL;
}
cifs_dbg(FYI, "SMB311 cipher type:%d\n", le16_to_cpu(ctxt->Ciphers[0]));
if ((ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_CCM) &&
(ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_GCM)) {
if (require_gcm_256) {
if (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES256_GCM) {
cifs_dbg(VFS, "Server does not support requested encryption type (AES256 GCM)\n");
return -EOPNOTSUPP;
}
} else if (ctxt->Ciphers[0] == 0) {
/* e.g. if server only supported AES256_CCM (very unlikely) */
cifs_dbg(VFS, "Server does not support requested encryption types\n");
return -EOPNOTSUPP;
} else if ((ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_CCM) &&
(ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_GCM) &&
(ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES256_GCM)) {
/* server returned a cipher we didn't ask for */
pr_warn_once("Invalid SMB3.11 cipher returned\n");
return -EINVAL;
}