It is useful to know why you callback called with NULL (i.e. it failed),
for example if you set max_body with evhttp_connection_set_max_body_size()
you must know that it failed because of body was longer than this size.
(Commit message tweaked by Nick)
Here is the brief description of problem:
When you are use evdns to resolve domains to IP adresses (see
./sample/dns-example) you loop never returns from event_base_dispatch(),
and because of this the program will never terminated.
Because existing programs may be depending on the old behavior, we
only apply the fix when evdns_base_new() is created with a new flag -
EVDNS_BASE_DISABLE_WHEN_INACTIVE.
(Commit message edited by Nick while squashing the branch.)
When resuming the system from a suspended state, the ev_timeout field
of a scheduled timer event may be in the past. This leads to
unexpected behavior when scheduling a short-duration timer event
immediately after returning from suspension, because the new event
does not land on top of the timeout minheap and so the event loop
(blocked on a possibly long-duration timeout) is not notified.
This patch checks for this condition and, if it obtains, notifies the
event loop.
This patch add check in evhttp_decode_uri_internal() that next 2 symbols
are exists in array of chars for decoding, if don't have two next 2
symbols don't try to decode '%FF'
Now, https-client accepts both:
https://ip.appspot.com/ (matching wildcard certificate)
https://github.com/ (matching non-wildcard certificate)
but still rejects
https://www.kegel.com/ (non-matching wildcard certificate)
which should match the behavior of these sites in a web browser.
sample/openssl_hostname_validation.c: In function 'matches_common_name':
sample/openssl_hostname_validation.c:80: warning: comparison between signed and unsigned integer expressions
sample/openssl_hostname_validation.c: In function 'matches_subject_alternative_name':
sample/openssl_hostname_validation.c:124: warning: comparison between signed and unsigned integer expressions
The problem is that if you go to a website whose certificate does not
match its hostname, it should fail. Try this in a web browser for
https://www.kegel.com/ for example. Your web browser will say the
certificate is for *.pair.com, not for www.kegel.com, and won't let
you visit it without clicking through a bunch of scary warnings.
However, prior to this commit, https-client was happy to fetch
https://www.kegel.com/ without complaining. That is bad. Now, with
this commit, it will properly complain, which is good:
pelletier@chives:~/src/libevent/sample$ ./https-client https://www.kegel.com/
Got 'MatchNotFound' for hostname 'www.kegel.com' and certificate:
/C=US/postalCode=15203/ST=Pennsylvania/L=Pittsburgh/street=Suite 210/street=2403 Sidney Street/O=pair Networks, Inc./OU=Provided by pair Networks, Inc./OU=PairWildcardSSL $250,000/CN=*.pair.com
some request failed - no idea which one though!
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
ppelletier@chives:~/src/libevent/sample$
It will still succeed for sites with an exactly-matching certificate,
such as https://github.com/ and that is also good!
However, the problem is that the iSECPartners code doesn't handle
wildcards, which means we reject https://ip.appspot.com/ even though
it is perfectly legitimate, because we don't understand the wildcard:
ppelletier@chives:~/src/libevent/sample$ ./https-client https://ip.appspot.com/
Got 'MatchNotFound' for hostname 'ip.appspot.com' and certificate:
/C=US/ST=California/L=Mountain View/O=Google Inc/CN=*.appspot.com
some request failed - no idea which one though!
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
ppelletier@chives:~/src/libevent/sample$
So, we need to fix this. In other words, "to be continued..."
as suggested here:
http://archives.seul.org/libevent/users/Feb-2013/msg00034.html
although curl's acinclude.m4 reveals many other possibilities:
dnl /etc/ssl/certs/ca-certificates.crt Debian systems
dnl /etc/pki/tls/certs/ca-bundle.crt Redhat and Mandriva
dnl /usr/share/ssl/certs/ca-bundle.crt old(er) Redhat
dnl /usr/local/share/certs/ca-root.crt FreeBSD
dnl /etc/ssl/cert.pem OpenBSD
dnl /etc/ssl/certs/ (ca path) SUSE
And none of these cover Windows :(
presumably this was meant to put a ">" before every line, but that
isn't what it does, since evbuffer_remove is simply returning
fixed-size chunks. So, when retrieving a document of more than 256
bytes (e. g. any nontrivial document), we got "> " and newlines thrown
in at very arbitrary places.
This made the difference between segfaulting and not segfaulting for
me when I run https-client, when I've built libevent using an OpenSSL
in a non-standard location.
In the same spirit as 1d9d5110a4aebf5833f6fd78bd0252affde0f4d0 and
d70af27d0152d0a87a25127faf215604beb8ffe0.
