previously, in order to detect and insert {variables} into error/stats
templates, tinyproxy iterated char-by-char over the input file, and would
try to parse anything inside {} pairs and treat it like a variable name.
this breaks CSS, and additionally it's dog slow as tinyproxy wrote every
single character to the client via a write syscall.
now we process line-by-line, and inspect all matches of the regex
\{[a-z]{1,32}\}. if the contents of the regex are a known variable name,
substitution is taking place. if not, the contents are passed as-is to
the client. also the chunks before and after matches are written in
a single syscall.
closes#108
it's quite unexpected for an application running foreground in a
terminal to keep running when the terminal is closed.
also in such a case (if file logging is disabled) there's no way to
see what's happening to the proxy.
inet_ntoa() uses a static buffer and is therefore not threadsafe.
additionally it has been deprecated by POSIX.
by using inet_ntop() instead the code has been made ipv6 aware.
note that this codepath was only entered in the unlikely event that
no hosts header was being passed to the proxy, i.e. pre-HTTP/1.1.
* check return values of memory allocation and abort gracefully
in out-of-memory situations
* use sblist (linear dynamic array) instead of linked list
- this removes one pointer per filter rule
- removes need to manually allocate/free every single list item
(instead block allocation is used)
- simplifies code
* remove storage of (unused) input rule
- removes one char* pointer per filter rule
- removes storage of the raw bytes of each filter rule
* add line number to display on out-of-memory/invalid regex situation
* replace duplicate filter_domain()/filter_host() code with a single
function filter_run()
- reduces code size and management effort
with these improvements, >1 million regex rules can be loaded with
4 GB of RAM, whereas previously it crashed with about 950K.
the list for testing was assembled from
http://www.shallalist.de/Downloads/shallalist.tar.gzcloses#20
the timeout option set by the config file wasn't respected at all
so it could happen that connections became stale and were never released,
which eventually caused tinyproxy to hit the limit of open connections and
never accepting new ones.
addresses #274
getsockname() requires addrlen to be set to the size of the sockaddr struct
passed as the addr, and a check whether the returned addrlen exceeds the
initially passed size (to determine whether the address returned is truncated).
with a request like "GET /\r\n\r\n" where length is 0 this caused the code
to assume success and use the values of the uninitialized sockaddr struct.
unlike other functions called from the config parser code,
anonymous_insert() accesses the global config variable rather than
passing it as an argument. however the global variable is only set
after successful loading of the entire config.
we fix this by adding a conf argument to each anonymous_* function,
passing the global pointer in calls done from outside the config
parser.
fixes#292
previously, default values were stored once into a static struct,
then on each reload item by item copied manually into a "new"
config struct.
this has proven to be errorprone, as additions in one of the 2
locations were not propagated to the second one, apart from
being simply a lot of gratuitous code.
we now simply load the default values directly into the config
struct to be used on each reload.
closes#283
as a side effect of not updating the config pointer when loading
the config file fails, the "FIXME" level comment to take appropriate
action in that case has been removed. the only issue remaining
when receiving a SIGHUP and encountering a malformed config file would
now be the case that output to syslog/logfile won't be resumed, if
initially so configured.
this is required so we can elegantly swap out an old config for a
new one in the future and remove lots of boilerplate from config
initialization code.
unfortunately this is a quite intrusive change as the config struct
was accessed in numerous places, but frankly it should have been
done via a pointer right from the start.
right now, we simply point to a static struct in main.c, so there
shouldn't be any noticeable changes in behaviour.
if daemon mode is used and neither logfile nor syslog options specified,
this is clearly a misconfiguration issue. don't try to be smart and work
around that, so less global state information is required.
also, this case is already checked for in main.c:334.
it is quite easy to bring down a proxy server by forcing it to make
connections to one of its own ports, because this will result in an endless
loop spawning more and more connections, until all available fds are exhausted.
since there's a potentially infinite number of potential DNS/ip addresses
resolving to the proxy, it is impossible to detect an endless loop by simply
looking at the destination ip address and port.
what *is* possible though is to record the ip/port tuples assigned to outgoing
connections, and then compare them against new incoming connections. if they
match, the sender was the proxy itself and therefore needs to reject that
connection.
fixes#199.
tinyproxy used to do a full hostname resolution whenever a new client
connection happened, which could cause very long delays (as reported in #198).
there's only a single place/scenario that actually requires a hostname, and
that is when an Allow/Deny rule exists for a hostname or domain, rather than
a raw IP address. since it is very likely this feature is not very widely used,
it makes absolute sense to only do the costly resolution when it is unavoidable.
since the write syscall is used instead of stdio, accesses have been
safe already, but it's better to use a mutex anyway to prevent out-
of-order writes.
if we don't handle these gracefully, pretty much every existing config
file will fail with an error, which is probably not very friendly.
the obsoleted config items can be made hard errors after the next
release.
the existing codebase used an elaborate and complex approach for
its parallelism:
5 different config file options, namely
- MaxClients
- MinSpareServers
- MaxSpareServers
- StartServers
- MaxRequestsPerChild
were used to steer how (and how many) parallel processes tinyproxy
would spin up at start, how many processes at each point needed to
be idle, etc.
it seems all preforked processes would listen on the server port
and compete with each other about who would get assigned the new
incoming connections.
since some data needs to be shared across those processes, a half-
baked "shared memory" implementation was provided for this purpose.
that implementation used to use files in the filesystem, and since
it had a big FIXME comment, the author was well aware of how hackish
that approach was.
this entire complexity is now removed. the main thread enters
a loop which polls on the listening fds, then spins up a new
thread per connection, until the maximum number of connections
(MaxClients) is hit. this is the only of the 5 config options
left after this cleanup. since threads share the same address space,
the code necessary for shared memory access has been removed.
this means that the other 4 mentioned config option will now
produce a parse error, when encountered.
currently each thread uses a hardcoded default of 256KB per thread
for the thread stack size, which is quite lavish and should be
sufficient for even the worst C libraries, but people may want
to tweak this value to the bare minimum, thus we may provide a new
config option for this purpose in the future.
i suspect that on heavily optimized C libraries such a musl, a
stack size of 8-16 KB per thread could be sufficient.
since the existing list implementation in vector.c did not provide
a way to remove a single item from an existing list, i added my
own list implementation from my libulz library which offers this
functionality, rather than trying to add an ad-hoc, and perhaps
buggy implementation to the vector_t list code. the sblist
code is contained in an 80 line C file and as simple as it can get,
while offering good performance and is proven bugfree due to years
of use in other projects.
The new code skips leading whitespaces before removing trailing
whitespaces and comments.
Without doing this, lines with leading whitespace are treated like empty
lines (i.e. they are ignored).
it was reported that because the fdset was only initialized once,
tinyproxy would fail to properly listen on more than one interface.
closes#214closes#127
RFC 1929 specifies that the user/pass auth subnegotation repurposes the version
field for the version of that specification, which is 1, not 5.
however there's quite a good deal of software out there which got it wrong and
replies with version 5 to a successful authentication, so let's just accept both
forms - other socks5 client programs like curl do the same.
closes#172
sbin/ is meant for programs only usable by root, but in tinyproxy's
case, regular users can and *should* use tinyproxy; meaning it is
preferable from a security PoV to use tinyproxy as regular user.
closes#15 for real.
the previous patch that was merged[0] was halfbaked and only removed
the warning part of the original patch from openwrt[1], but didn't
actually activate bind support. further it invoked UB by removing
the return value from the function, if transparent proxy support was
compiled in.
[0]: d97d486d53
[1]: 7c01da4a72
just like the rest of the socks code, this was stolen from
proxychains-ng, of which i'm happen to be the maintainer of,
so it's not an issue (the licenses are identical, too).
tinyproxy uses a curious mechanism to log those early messages
that result from parsing the config file before the logging mechanism
has been properly set up yet by finishing parsing of the config file:
those early messages are written into a memory buffer and then
are printed later on. this slipped my attention when making it possible
to log to stdout in ccbbb81a.
