This temporarily breaks HTTP digest authentication in SSPI based builds,
causing CURLE_NOT_BUILT_IN to be returned. A follow up commit will
resume normal operation.
Typically the USE_WINDOWS_SSPI definition would not be used when the
CURL_DISABLE_CRYPTO_AUTH define is, however, it is still a valid build
configuration and, as such, the SASL Kerberos V5 (GSSAPI) authentication
data structures and functions would incorrectly be used when they
shouldn't be.
Introduced a new USE_KRB5 definition that takes into account the use of
CURL_DISABLE_CRYPTO_AUTH like USE_SPNEGO and USE_NTLM do.
Updated Curl_sasl_create_digest_md5_message() to use a dynamic buffer
for the SPN generation via the recently introduced Curl_sasl_build_spn()
function rather than a fixed buffer of 128 characters.
Various parts of the libcurl source code build a SPN for inclusion in
authentication data. This information is either used by our own native
generation routines or passed to authentication functions in third-party
libraries such as SSPI. However, some of these instances use fixed
buffers rather than dynamically allocated ones and not all of those that
should, convert to wide character strings in Unicode builds.
Implemented a common function that generates a SPN and performs the
wide character conversion where necessary.
They were added because of an older code path that used allocations and
should not have been left in the code. With this change the logic goes
back to how it was.
Curl_rand() will return a dummy and repatable random value for this
case. Makes it possible to write test cases that verify output.
Also, fake timestamp with CURL_FORCETIME set.
Only when built debug enabled of course.
Curl_ssl_random() was not used anymore so it has been
removed. Curl_rand() is enough.
create_digest_md5_message: generate base64 instead of hex string
curl_sasl: also fix memory leaks in some OOM situations
The SASL/Digest previously used the current time's seconds +
microseconds to add randomness but it is much better to instead get more
data from Curl_rand().
It will also allow us to easier "fake" that for debug builds on demand
in a future.
Rather than use a short 8-byte hex string, extended the cnonce to be
32-bytes long, like Windows SSPI does.
Used a combination of random data as well as the current date and
time for the generation.
Whilst the qop directive isn't required to be present in a client's
response, as servers should assume a qop of "auth" if it isn't
specified, some may return authentication failure if it is missing.
Given that we presently support "auth" and not "auth-int" or "auth-conf"
for native challenge-response messages, added client side validation of
the quality-of-protection options from the server's challenge message.
Added the ability to generated a base64 encoded XOAUTH2 token
containing: "user=<username>^Aauth=Bearer <bearer token>^A^A"
as per RFC6749 "OAuth 2.0 Authorization Framework".
Use appropriately sized buffers on the heap instead of fixed-size
buffers on the stack, to allow for longer usernames and passwords.
Callers never pass anything longer than MAX_CURL_USER_LENGTH (resp.
MAX_CURL_PASSWORD_LENGTH), so no functional change inteded yet.
When doing multi-part formposts, libcurl used a pseudo-random value that
was seeded with time(). This turns out to be bad for users who formpost
data that is provided with users who then can guess how the boundary
string will look like and then they can forge a different formpost part
and trick the receiver.
My advice to such implementors is (still even after this change) to not
rely on the boundary strings being cryptographically strong. Fix your
code and logic to not depend on them that much!
I moved the Curl_rand() function into the sslgen.c source file now to be
able to take advantage of the SSL library's random function if it
provides one. If not, try to use the RANDOM_FILE for seeding and as a
last resort keep the old logic, just modified to also add microseconds
which makes it harder to properly guess the exact seed.
The formboundary() function in formdata.c is now using 64 bit entropy
for the boundary and therefore the string of dashes was reduced by 4
letters and there are 16 hex digits following it. The total length is
thus still the same.
Bug: http://curl.haxx.se/bug/view.cgi?id=1251
Reported-by: "Floris"
Fixed a null pointer reference when an empty challenge is passed to the
Curl_sasl_create_digest_md5_message() function.
Bug: http://sourceforge.net/p/curl/bugs/1193/
Reported by: Saran Neti
When negotiating SASL DIGEST-MD5 authentication, the function
Curl_sasl_create_digest_md5_message() uses the data provided from the
server without doing the proper length checks and that data is then
appended to a local fixed-size buffer on the stack.
This vulnerability can be exploited by someone who is in control of a
server that a libcurl based program is accessing with POP3, SMTP or
IMAP. For applications that accept user provided URLs, it is also
thinkable that a malicious user would feed an application with a URL to
a server hosting code targetting this flaw.
Bug: http://curl.haxx.se/docs/adv_20130206.html
