Use the new library CURLOPT_TCP_KEEPALIVE rather than disabling this via
the sockopt callback. If --keepalive-time is used, apply the value to
CURLOPT_TCP_KEEPIDLE and CURLOPT_TCP_KEEPINTVL.

This adds three new options to control the behavior of TCP keepalives:

- CURLOPT_TCP_KEEPALIVE: enable/disable probes
- CURLOPT_TCP_KEEPIDLE: idle time before sending first probe
- CURLOPT_TCP_KEEPINTVL: delay between successive probes

While not all operating systems support the TCP_KEEPIDLE and
TCP_KEEPINTVL knobs, the library will still allow these options to be
set by clients, silently ignoring the values.

When CURLOPT_REFERER has been used, curl_easy_reset() did not properly
clear it.

Verified with the new test 598

Bug: http://curl.haxx.se/bug/view.cgi?id=3481551
Reported by: Michael Day

This prevents clobbering of non recoverable error return codes while
retaining intended functionality of commit 65103efe

We want to continue to the next URL to try even on failures returned
from libcurl. This makes -f with ranges still get subsequent URLs even
if occasional ones return error. This was a regression as it used to
work and broke in the 7.23.0 release.

Added test case 1328 to verify the fix.

Bug: http://curl.haxx.se/bug/view.cgi?id=3481223
Reported by: Juan Barreto

When the target host was given as a IPv6 numerical address, it was not
properly put within square brackets for the Host: header in the CONNECT
request. The "normal" request did fine.

Reported by: "zooloo"
Bug: http://curl.haxx.se/bug/view.cgi?id=3482093

When support for nettle was added in 64f328c7, I overlooked
the fact that AC_CHECK_LIB doesn't add the tested lib to LIBS
if the check succeeded, if a custom success code block was present.
(The previous version of the check had an empty block for
successful checks, adding the lib to LIBS implicitly.)

Therefore, explicitly add either nettle or gcrypt to LIBS, after
deciding which one to use. Even if they can be linked in
transitively, it is safer to actually link explicitly to them.

This fixes building with gnutls with linkers that don't allow
linking transitively, such as for windows.

When connecting to a domain with multiple IP addresses, allow different,
decreasing connection timeout values. This should guarantee some
connections attempts with sufficiently long timeouts, while still
providing fallback.

Synced and prepared for 7.24.0 release. Two security problems, one bug fix,
two more contributors.

With advice from Nikos Mavrogiannopoulos, changed the priority string to
add "actual priorities" and favour ARCFOUR. This makes libcurl work
better when enforcing SSLv3 with GnuTLS. Both in the sense that the
libmicrohttpd test is now working again but also that it mitigates a
weakness in the older SSL/TLS protocols.

Bug: http://curl.haxx.se/mail/lib-2012-01/0225.html
Reported by: Christian Grothoff

Related to the security vulnerability: CVE-2012-0036

Bug: http://curl.haxx.se/docs/adv_20120124.html

Protocols (IMAP, POP3 and SMTP) that use the path part of a URL in a
decoded manner now use the new Curl_urldecode() function to reject URLs
with embedded control codes (anything that is or decodes to a byte value
less than 32).

URLs containing such codes could easily otherwise be used to do harm and
allow users to do unintended actions with otherwise innocent tools and
applications. Like for example using a URL like
pop3://pop3.example.com/1%0d%0aDELE%201 when the app wants a URL to get
a mail and instead this would delete one.

This flaw is considered a security vulnerability: CVE-2012-0036

Security advisory at: http://curl.haxx.se/docs/adv_20120124.html

Reported by: Dan Fandrich

OpenSSL added a work-around for a SSL 3.0/TLS 1.0 CBC vulnerability
(http://www.openssl.org/~bodo/tls-cbc.txt). In 0.9.6e they added a bit
to SSL_OP_ALL that _disables_ that work-around despite the fact that
SSL_OP_ALL is documented to do "rather harmless" workarounds.

The libcurl code uses the SSL_OP_ALL define and thus logically always
disables the OpenSSL fix.

In order to keep the secure work-around workding, the
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS bit must not be set and this change
makes sure of this.

Reported by: product-security at Apple

3 more bugfixes, 3 more contributors

Using a URL with embedded user name and password didn't work if the host
was given as a numerical IPv6 string, like ftp://user:password@[::1]/

Reported by: Brandon Wang
Bug: http://curl.haxx.se/mail/archive-2012-01/0047.html

avoid checking preprocessor definition official value

As is pointed out in this bug report, there can indeed be situation
where --stderr has a point even when the "real" stderr can be
redirected. Remove the superfluous and wrong comment.

bug: http://curl.haxx.se/bug/view.cgi?id=3476020

http://curl.haxx.se/bug/view.cgi?id=3438362

Apparently ssl_get_ciphersuite() is needed to get the name of the used
cipher suite.

The value was turned negative when it shouldn't have been

... it is now named havege_random!

Reported by: Robert Schumann
Bug: http://curl.haxx.se/mail/lib-2012-01/0178.html

5 more bug fixes, 1 more contributor

Add simple telnet tests which (ab)use the http server.
The second test checks for an input file handling bug.

Remove wrongly implemented optimisation of telnet upload, apparently
intended to allow the library to avoid manually polling for input.

Fix a bug where input was read from stdin even when a different FILE *
had been configured via CURLOPT_READDATA

bug: http://curl.haxx.se/bug/view.cgi?id=3474308