it turned out that calling dlsym() may call malloc() in turn,
so we end up with the same deadlock described in the latest commit.
we thus now put all the fds passed to close pre-init into a list
and close them at init time.
this may finally fix#119.
it was observed that it is a bad idea to initialize the entire
infrastructure used by proxychains from the close hook,
because the following scenario will lead to a deadlock:
- it is possible that the dynlinker executes the initializer code of
other shared libs first
- if that code directly or indirectly calls malloc()
- which calls close() if it decided to use an mmap based allocation
- will now call our close(), which does
- call pthread_once which requires a lock
- creates a thread which calls malloc()
- which in turn calls our close() another time
- and our close is still in locked state.
so it seems the only save thing to do is to just get the address
of the original close function, and call that when we're in a
pre-init state.
this may hold for other functions that do lazy initialization as well,
however for those just calling the original function is probably
undesired since that could result in unproxified connections.
it will be needed to analyze on a per-function basis what the best
thing to do is, and finally rely only on the execution of the init
function from the gcc initializer.
should fix#119
hostsreader_get() used to assign the IP address to both `name` and `ip`
fields in `struct hostsreader`, which led to proxychains effectively
ignoring the contents of /etc/hosts.
if an ipv4-mapped ipv6 address is detected, the ip is converted
into v4 format because it may actually be one of our remote dns ips.
it was reported that a program called "maven", when getting handed our
fake ips in the remote dns subnet, converts the ip to v6 prior to calling
connect():
[proxychains] Strict chain ... 127.0.0.1:1080 ... ::ffff:224.0.0.1:443
<--socket error or timeout!
fixes#77
only basic testing was done (with 2 socks5 proxies listening on ::1)
but seems to work as intended.
ipv6 support for the hostsreader (/etc/hosts) is not implemented so far.
since "user" always points to a statically allocated string buffer,
the test for if(user)... was bogus.
use ulen instead.
this bug should only be visible on socks servers that require auth
if username was not passed, so it was probably not really an issue.
the allocatorthread got pointers to RAM which were reallocated
behind the back, and if realloc() couldn't grow in-place, lead
to segfaults in applications that do a lot of DNS-lookups such
as webbrowsers.
closes#66closes#31
thanks to @ravomavain for tracking down the issue.
working directly with the passed variables could lead to bugs when
some lines in the hosts file aren't well-formed and the loop is taken
several times while the buf vars are already modified.
the hostentdb introduced between 4.2 and 4.3
(via af5c6f0c6a )
had several issues:
- it caused breakage on FreeBSD and was commented out there
- prevented usage of the hostdb when proxy_dns was turned off
(issue #42)
- required dynamic memory allocation which was accessed from several
threads
- wouldnt reflect changes to the hosts file made during program run
the only sensible solution is to remove the hostentdb and replace it
with a home-grown hosts parser (we can't use gethostent() since
that would mess up the gethostent()-state from different threads).
the new parser used here is deliberately held simple and only meant
to provide the user with means to reference hardcoded ipv4 addresses
via his hosts file.
fixes#42
some broken programs like pulseaudio rely on LD_PRELOAD hacks to function,
if we just override the environment variable, those will stop working.
simplified version of patch suggested by @hexchain
closes#35
the strncpy function is both dangerous and slow.
dangerous because it doesn't do what the naive programmer expects
(bounded strcpy), and slow because it pads the entire bufsize
with zeroes.
