`CURLINFO_PROXYAUTH_AVAIL` is 0 after resetting user name and password

[sergio-nsk]

I did this

Simplified code

    CURL *curl = curl_easy_init();
    ASSERT_NE(curl, nullptr);

    curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/");
    curl_easy_setopt(curl, CURLOPT_PROXY, "http://digest-proxy:80");
    curl_easy_perform(curl);

    long code = 0;
    long auth = 0;
    curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
    curl_easy_getinfo(curl, CURLINFO_PROXYAUTH_AVAIL, &auth);
    EXPECT_EQ(code, 407);
    EXPECT_EQ(auth, CURLAUTH_DIGEST);

    curl_easy_setopt(curl, CURLOPT_PROXYAUTH, CURLAUTH_DIGEST);
    curl_easy_setopt(curl, CURLOPT_PROXYUSERNAME, "usr");
    curl_easy_setopt(curl, CURLOPT_PROXYPASSWORD, "pswrd");
    curl_easy_perform(curl);

    char *location;
    curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
    curl_easy_getinfo(curl, CURLINFO_PROXYAUTH_USED, &auth);
    curl_easy_getinfo(curl, CURLINFO_REDIRECT_URL, &location);
    EXPECT_EQ(code, 301);
    EXPECT_EQ(auth, CURLAUTH_DIGEST);  // Fail: 0 != 2
    EXPECT_STREQ(location, "https://example.com");

    // Redirection

    curl_easy_setopt(curl, CURLOPT_PROXYUSERNAME, nullptr);
    curl_easy_setopt(curl, CURLOPT_PROXYPASSWORD, nullptr);
    curl_easy_setopt(curl, CURLOPT_URL, location);
    curl_easy_perform(curl);

    curl_easy_getinfo(curl, CURLINFO_HTTP_CONNECTCODE, &code);
    curl_easy_getinfo(curl, CURLINFO_PROXYAUTH_AVAIL, &auth);
    EXPECT_EQ(code, 407);
    EXPECT_EQ(auth, CURLAUTH_DIGEST);  // Fail: 0 != 2

    curl_easy_cleanup(curl);

• Getting http://example.com/ through a proxy with the digest authentication.
• Receiving 407. CURLINFO_PROXYAUTH_AVAIL is 2 - OK
• Setting a proxy user name and password, getting http://example.com/ again.
• Receiving 301. CURLINFO_PROXYAUTH_USED is 0, expected 2 - FAIL.
• Setting a new url and resetting a proxy user name and password.
• Receiving 407. CURLINFO_PROXYAUTH_AVAIL is 0 expected 2 - FAIL.

The issue seems to be in the function auth_digest(), it does not set data->info.proxyauthavail if data->state.authproxy.avail is set previously.

I expected the following

No response

curl/libcurl version

curl 8.17.0

operating system

Windows 10

[icing]

Thanks for the report. I think there is some inconsistency in how CURLINFO_PROXYAUTH_AVAIL and CURLINFO_PROXYAUTH_USED (and the corresponding CURLINFO_HTTPAUTH_AVAIL and CURLINFO_HTTPAUTH_USED) are handled.

I made a fix in #21275 that should solve the first assertion failure in your example. As to the second fail, I believe you are right that the code that wants to prevent duplicate Digest auth appearances then mistakenly also prevents the update of the AVAIL flag.

Which made me look at the code that populates proxyauthavail and httpauthavail. And I think it needs a general change.

@bagder, the avail bits are only set for methods supported by curl and that seems wrong. Should we not report all auth methods known to us? We cannot pick them if not supported, of course, but the avail flags seem to be for information only, AFAICT. Any opinion?

if the semantics of the avail bits is "available and supported*, then I'll just change digest to always set it.

[bagder]

I think it needs to be "available and supported" since there could be any number of unknown auth methods otherwise and libcurl can't provide a bitmask for those.

[icing]

I think it needs to be "available and supported" since there could be any number of unknown auth methods otherwise and libcurl can't provide a bitmask for those.

Ok, just made the minimal change in #21275.

@sergio-nsk would you be able to test with that PR? Thanks!

[sergio-nsk]

Thank you for the prompt fix! I will test the fix in the evening.

[sergio-nsk]

Confirm, #21284 and #21285 work well and have fixed my issue.
The latter seems to include the change of the former.