smb3: add support for IAKerb

There are now more servers which advertise support for IAKerb (passthrough
Kerberos authentication via proxy).  IAKerb is a public extension industry
standard Kerberos protocol that allows a client without line-of-sight
to a Domain Controller to authenticate. There can be cases where we
would fail to mount if the server only advertises the OID for IAKerb
in SPNEGO/GSSAPI.  Add code to allow us to still upcall to userspace
in these cases to obtain the Kerberos ticket.

Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Steve French 2025-01-28 01:04:23 -06:00
parent 021840c142
commit eea5119fa5
5 changed files with 12 additions and 3 deletions

View File

@ -52,6 +52,8 @@ int cifs_neg_token_init_mech_type(void *context, size_t hdrlen,
server->sec_kerberos = true;
else if (oid == OID_ntlmssp)
server->sec_ntlmssp = true;
else if (oid == OID_IAKerb)
server->sec_iakerb = true;
else {
char buf[50];

View File

@ -138,11 +138,13 @@ cifs_get_spnego_key(struct cifs_ses *sesInfo,
dp = description + strlen(description);
/* for now, only sec=krb5 and sec=mskrb5 are valid */
/* for now, only sec=krb5 and sec=mskrb5 and iakerb are valid */
if (server->sec_kerberos)
sprintf(dp, ";sec=krb5");
else if (server->sec_mskerberos)
sprintf(dp, ";sec=mskrb5");
else if (server->sec_iakerb)
sprintf(dp, ";sec=iakerb");
else {
cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
sprintf(dp, ";sec=krb5");

View File

@ -151,6 +151,7 @@ enum securityEnum {
NTLMv2, /* Legacy NTLM auth with NTLMv2 hash */
RawNTLMSSP, /* NTLMSSP without SPNEGO, NTLMv2 hash */
Kerberos, /* Kerberos via SPNEGO */
IAKerb, /* Kerberos proxy */
};
enum upcall_target_enum {
@ -781,6 +782,7 @@ struct TCP_Server_Info {
bool sec_kerberosu2u; /* supports U2U Kerberos */
bool sec_kerberos; /* supports plain Kerberos */
bool sec_mskerberos; /* supports legacy MS Kerberos */
bool sec_iakerb; /* supports pass-through auth for Kerberos (krb5 proxy) */
bool large_buf; /* is current buffer large? */
/* use SMBD connection instead of socket */
bool rdma;
@ -2148,6 +2150,8 @@ static inline char *get_security_type_str(enum securityEnum sectype)
return "Kerberos";
case NTLMv2:
return "NTLMv2";
case IAKerb:
return "IAKerb";
default:
return "Unknown";
}

View File

@ -1235,12 +1235,13 @@ cifs_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
switch (requested) {
case Kerberos:
case RawNTLMSSP:
case IAKerb:
return requested;
case Unspecified:
if (server->sec_ntlmssp &&
(global_secflags & CIFSSEC_MAY_NTLMSSP))
return RawNTLMSSP;
if ((server->sec_kerberos || server->sec_mskerberos) &&
if ((server->sec_kerberos || server->sec_mskerberos || server->sec_iakerb) &&
(global_secflags & CIFSSEC_MAY_KRB5))
return Kerberos;
fallthrough;

View File

@ -1429,7 +1429,7 @@ smb2_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
if (server->sec_ntlmssp &&
(global_secflags & CIFSSEC_MAY_NTLMSSP))
return RawNTLMSSP;
if ((server->sec_kerberos || server->sec_mskerberos) &&
if ((server->sec_kerberos || server->sec_mskerberos || server->sec_iakerb) &&
(global_secflags & CIFSSEC_MAY_KRB5))
return Kerberos;
fallthrough;