The function compat_getdelim_ is used for tor_getline if tor is compiled
on a system that lacks getline and getdelim. These systems should be
very rare, considering that getdelim is POSIX.
If this system is further a 32 bit architecture, it is possible to
trigger a double free with huge files.
If bufsiz has been already increased to 2 GB, the next chunk would
be 4 GB in size, which wraps around to 0 due to 32 bit limitations.
A realloc(*buf, 0) could be imagined as "free(*buf); return malloc(0);"
which therefore could return NULL. The code in question considers
that an error, but will keep the value of *buf pointing to already
freed memory.
The caller of tor_getline() would free the pointer again, therefore
leading to a double free.
This code can only be triggered in dirserv_read_measured_bandwidths
with a huge measured bandwith list file on a system that actually
allows to reach 2 GB of space through realloc.
It is not possible to trigger this on Linux with glibc or other major
*BSD systems even on unit tests, because these systems cannot reach
so much memory due to memory fragmentation.
This patch is effectively based on the penetration test report of
cure53 for curl available at https://cure53.de/pentest-report_curl.pdf
and explained under section "CRL-01-007 Double-free in aprintf() via
unsafe size_t multiplication (Medium)".
If the concatenation of connection buffer and the buffer of linked
connection exceeds INT_MAX bytes, then buf_move_to_buf returns -1 as an
error value.
This value is currently casted to size_t (variable n_read) and will
erroneously lead to an increasement of variable "max_to_read".
This in turn can be used to call connection_buf_read_from_socket to
store more data inside the buffer than expected and clogging the
connection buffer.
If the linked connection buffer was able to overflow INT_MAX, the call
of buf_move_to_buf would have previously internally triggered an integer
overflow, corrupting the state of the connection buffer.
Protect buffers against INT_MAX datalen overflows.
Many buffer functions have a hard limit of INT_MAX for datalen, but
this limitation is not enforced in all functions:
- buf_move_all may exceed that limit with too many chunks
- buf_move_to_buf exceeds that limit with invalid buf_flushlen argument
- buf_new_with_data may exceed that limit (unit tests only)
This patch adds some annotations in some buf_pos_t functions to
guarantee that no out of boundary access could occur even if another
function lacks safe guards against datalen overflows.
Nick Mathewson [Mon, 8 Apr 2019 21:02:14 +0000 (17:02 -0400)]
Detect and suppress an additional gmtime() warning in test_util.c
Fixes bug 29922; bugfix on 0.2.9.3-alpha when we tried to capture
all these warnings. No need to backport any farther than 0.3.5,
though -- these warnings don't cause test failures before then.
This one was tricky to find because apparently it only happened on
_some_ windows builds.
Nick Mathewson [Fri, 29 Mar 2019 17:38:48 +0000 (13:38 -0400)]
NSS: disable TLS1.2 SHA-384 ciphersuites.
In current NSS versions, these ciphersuites don't work with
SSL_ExportKeyingMaterial(), which was causing relays to fail when
they tried to negotiate the v3 link protocol authentication.
Mike Perry [Fri, 5 Apr 2019 00:21:07 +0000 (00:21 +0000)]
Bug #29500: Fix monotime mocking in circpad unittests.
Our monotime mocking forces us to call monotime_init() *before* we set the
mocked time value. monotime_init() thus stores the first ratchet value at
whatever the platform is at, and then we set fake mocked time to some later
value.
If monotime_init() gets a value from the host that is greater than what we
choose to mock time at for our unittests, all subsequent monotime_abosolute()
calls return zero, which breaks all unittests that depend on time moving
forward by updating mocked monotime values.
So, we need to adjust our mocked time to take the weird monotime_init() time
into account, when we set fake time.
Nick Mathewson [Wed, 6 Mar 2019 16:03:42 +0000 (11:03 -0500)]
fast_rng: if noinherit has failed, then check getpid() for bad forks
getpid() can be really expensive sometimes, and it can fail to
detect some kind of fork+prng mistakes, so we need to avoid it if
it's safe to do so.
This patch might slow down fast_prng a lot on any old operating
system that lacks a way to prevent ram from being inherited, AND
requires a syscall for any getpid() calls. But it should make sure
that we either crash or continue safely on incorrect fork+prng usage
elsewhere in the future.
Nick Mathewson [Thu, 4 Apr 2019 15:24:55 +0000 (11:24 -0400)]
Do not cache bogus results from classifying client ciphers
When classifying a client's selection of TLS ciphers, if the client
ciphers are not yet available, do not cache the result. Previously,
we had cached the unavailability of the cipher list and never looked
again, which in turn led us to assume that the client only supported
the ancient V1 link protocol. This, in turn, was causing Stem
integration tests to stall in some cases. Fixes bug 30021; bugfix
on 0.2.4.8-alpha.
Nick Mathewson [Wed, 3 Apr 2019 18:30:56 +0000 (14:30 -0400)]
Improve logging for 28614.
When we fixed 28614, our answer was "if we failed to load the
consensus on windows and it had a CRLF, retry it." But we logged
the failure at "warn", and we only logged the retry at "info".
Now we log the retry at "notice", with more useful information.
projects / thirdparty / tor.git / log
