digest_sspi: Don't reuse context if the user/passwd has changed

Bug: https://github.com/curl/curl/issues/1685
Reported-by: paulharris@users.noreply.github.com

Assisted-by: Isaac Boukris

Closes https://github.com/curl/curl/pull/1742

2 files changed, 45 insertions, 0 deletions

diff --git a/lib/urldata.h b/lib/urldata.h
index 45ad04e0a..b4f18e7da 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -417,6 +417,10 @@ struct digestdata {
   BYTE *input_token;
   size_t input_token_len;
   CtxtHandle *http_context;
+  /* copy of user/passwd used to make the identity for http_context.
+     either may be NULL. */
+  char *user;
+  char *passwd;
 #else
   char *nonce;
   char *cnonce;
diff --git a/lib/vauth/digest_sspi.c b/lib/vauth/digest_sspi.c
index 0bd94442d..f5d619c99 100644
--- a/lib/vauth/digest_sspi.c
+++ b/lib/vauth/digest_sspi.c
@@ -438,6 +438,20 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
     return CURLE_OUT_OF_MEMORY;
   }
 
+  /* If the user/passwd that was used to make the identity for http_context
+     has changed then delete that context. */
+  if((userp && !digest->user) || (!userp && digest->user) ||
+     (passwdp && !digest->passwd) || (!passwdp && digest->passwd) ||
+     (userp && digest->user && strcmp(userp, digest->user)) ||
+     (passwdp && digest->passwd && strcmp(passwdp, digest->passwd))) {
+    if(digest->http_context) {
+      s_pSecFn->DeleteSecurityContext(digest->http_context);
+      Curl_safefree(digest->http_context);
+    }
+    Curl_safefree(digest->user);
+    Curl_safefree(digest->passwd);
+  }
+
   if(digest->http_context) {
     chlg_desc.ulVersion    = SECBUFFER_VERSION;
     chlg_desc.cBuffers     = 5;
@@ -479,6 +493,10 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
     TimeStamp expiry; /* For Windows 9x compatibility of SSPI calls */
     TCHAR *spn;
 
+    /* free the copy of user/passwd used to make the previous identity */
+    Curl_safefree(digest->user);
+    Curl_safefree(digest->passwd);
+
     if(userp && *userp) {
       /* Populate our identity structure */
       if(Curl_create_sspi_identity(userp, passwdp, &identity)) {
@@ -500,6 +518,25 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
       /* Use the current Windows user */
       p_identity = NULL;
 
+    if(userp) {
+      digest->user = strdup(userp);
+
+      if(!digest->user) {
+        free(output_token);
+        return CURLE_OUT_OF_MEMORY;
+      }
+    }
+
+    if(passwdp) {
+      digest->passwd = strdup(passwdp);
+
+      if(!digest->passwd) {
+        free(output_token);
+        Curl_safefree(digest->user);
+        return CURLE_OUT_OF_MEMORY;
+      }
+    }
+
     /* Acquire our credentials handle */
     status = s_pSecFn->AcquireCredentialsHandle(NULL,
                                                 (TCHAR *) TEXT(SP_NAME_DIGEST),
@@ -623,6 +660,10 @@ void Curl_auth_digest_cleanup(struct digestdata *digest)
     s_pSecFn->DeleteSecurityContext(digest->http_context);
     Curl_safefree(digest->http_context);
   }
+
+  /* Free the copy of user/passwd used to make the identity for http_context */
+  Curl_safefree(digest->user);
+  Curl_safefree(digest->passwd);
 }
 
 #endif /* USE_WINDOWS_SSPI && !CURL_DISABLE_CRYPTO_AUTH */