Permalink
Browse files

spnego_sspi: add support for channel binding

Attempt to add support for Secure Channel binding when negotiate
authentication is used. The problem to solve is that by default IIS
accepts channel binding and curl doesn't utilise them. The result was a
401 response. Scope affects only the Schannel(winssl)-SSPI combination.

Fixes #3503
Closes #3509
  • Loading branch information...
georgeok authored and MarcelRaad committed Jan 29, 2019
1 parent 463f16d commit a730432e59754df97c8985eb3094ca1cdd3e4955
Showing with 49 additions and 8 deletions.
  1. +5 −0 lib/http_negotiate.c
  2. +3 −0 lib/http_ntlm.c
  3. +6 −0 lib/urldata.h
  4. +34 −7 lib/vauth/spnego_sspi.c
  5. +1 −1 lib/vtls/schannel.c
@@ -89,6 +89,11 @@ CURLcode Curl_input_negotiate(struct connectdata *conn, bool proxy,
}
}

/* Supports SSL channel binding for Windows ISS extended protection */
#if defined(USE_WINDOWS_SSPI) && defined(SECPKG_ATTR_ENDPOINT_BINDINGS)
neg_ctx->sslContext = conn->sslContext;
#endif

/* Initialize the security context and decode our challenge */
result = Curl_auth_decode_spnego_message(data, userp, passwdp, service,
host, header, neg_ctx);
@@ -175,6 +175,9 @@ CURLcode Curl_output_ntlm(struct connectdata *conn, bool proxy)
if(s_hSecDll == NULL)
return err;
}
#ifdef SECPKG_ATTR_ENDPOINT_BINDINGS
ntlm->sslContext = conn->sslContext;
#endif
#endif

switch(ntlm->state) {
@@ -364,6 +364,9 @@ struct negotiatedata {
gss_buffer_desc output_token;
#else
#ifdef USE_WINDOWS_SSPI
#ifdef SECPKG_ATTR_ENDPOINT_BINDINGS
CtxtHandle *sslContext;
#endif
DWORD status;
CredHandle *credentials;
CtxtHandle *context;
@@ -980,6 +983,9 @@ struct connectdata {
void *seek_client; /* pointer to pass to the seek() above */

/*************** Request - specific items ************/
#if defined(USE_WINDOWS_SSPI) && defined(SECPKG_ATTR_ENDPOINT_BINDINGS)
CtxtHandle *sslContext;
#endif

#if defined(USE_NTLM)
struct ntlmdata ntlm; /* NTLM differs from other authentication schemes
@@ -92,7 +92,7 @@ CURLcode Curl_auth_decode_spnego_message(struct Curl_easy *data,
size_t chlglen = 0;
unsigned char *chlg = NULL;
PSecPkgInfo SecurityPackage;
SecBuffer chlg_buf;
SecBuffer chlg_buf[2];
SecBuffer resp_buf;
SecBufferDesc chlg_desc;
SecBufferDesc resp_desc;
@@ -189,12 +189,39 @@ CURLcode Curl_auth_decode_spnego_message(struct Curl_easy *data,
}

/* Setup the challenge "input" security buffer */
chlg_desc.ulVersion = SECBUFFER_VERSION;
chlg_desc.cBuffers = 1;
chlg_desc.pBuffers = &chlg_buf;
chlg_buf.BufferType = SECBUFFER_TOKEN;
chlg_buf.pvBuffer = chlg;
chlg_buf.cbBuffer = curlx_uztoul(chlglen);
chlg_desc.ulVersion = SECBUFFER_VERSION;
chlg_desc.cBuffers = 1;
chlg_desc.pBuffers = &chlg_buf[0];
chlg_buf[0].BufferType = SECBUFFER_TOKEN;
chlg_buf[0].pvBuffer = chlg;
chlg_buf[0].cbBuffer = curlx_uztoul(chlglen);

#ifdef SECPKG_ATTR_ENDPOINT_BINDINGS
/* ssl context comes from Schannel.
* When extended protection is used in IIS server,
* we have to pass a second SecBuffer to the SecBufferDesc
* otherwise IIS will not pass the authentication (401 response).
* Minimum supported version is Windows 7.
* https://docs.microsoft.com/en-us/security-updates
* /SecurityAdvisories/2009/973811
*/
if(nego->sslContext) {
SEC_CHANNEL_BINDINGS channelBindings;
SecPkgContext_Bindings pkgBindings;
pkgBindings.Bindings = &channelBindings;
nego->status = s_pSecFn->QueryContextAttributes(
nego->sslContext,
SECPKG_ATTR_ENDPOINT_BINDINGS,
&pkgBindings
);
if(nego->status == SEC_E_OK) {
chlg_desc.cBuffers++;
chlg_buf[1].BufferType = SECBUFFER_CHANNEL_BINDINGS;
chlg_buf[1].cbBuffer = pkgBindings.BindingsLength;
chlg_buf[1].pvBuffer = pkgBindings.Bindings;
}
}
#endif
}

/* Setup the response "output" security buffer */
@@ -1428,7 +1428,7 @@ schannel_connect_common(struct connectdata *conn, int sockindex,
* binding to pass the IIS extended protection checks.
* Available on Windows 7 or later.
*/
conn->ntlm.sslContext = &BACKEND->ctxt->ctxt_handle;
conn->sslContext = &BACKEND->ctxt->ctxt_handle;
#endif

*done = TRUE;

0 comments on commit a730432

Please sign in to comment.