mirror of
https://gitlab.torproject.org/tpo/core/tor.git
synced 2024-12-06 19:41:15 +01:00
Tobias Stoeckmann
17458a87d7
Overflowing a signed integer in C is an undefined behaviour. It is possible to trigger this undefined behaviour in tor_asprintf on Windows or systems lacking vasprintf. On these systems, eiter _vscprintf or vsnprintf is called to retrieve the required amount of bytes to hold the string. These functions can return INT_MAX. The easiest way to recreate this is the use of a specially crafted configuration file, e.g. containing the line: FirewallPorts AAAAA<in total 2147483610 As> This line triggers the needed tor_asprintf call which eventually leads to an INT_MAX return value from _vscprintf or vsnprintf. The needed byte for \0 is added to the result, triggering the overflow and therefore the undefined behaviour. Casting the value to size_t before addition fixes the behaviour. Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Tor protects your privacy on the internet by hiding the connection
between your Internet address and the services you use. We believe Tor
is reasonably secure, but please ensure you read the instructions and
configure it properly.
To build Tor from source:
./configure && make && make install
To build Tor from a just-cloned git repository:
sh autogen.sh && ./configure && make && make install
Home page:
https://www.torproject.org/
Download new versions:
https://www.torproject.org/download/download.html
Documentation, including links to installation and setup instructions:
https://www.torproject.org/docs/documentation.html
Making applications work with Tor:
https://wiki.torproject.org/projects/tor/wiki/doc/TorifyHOWTO
Frequently Asked Questions:
https://www.torproject.org/docs/faq.html
To get started working on Tor development:
See the doc/HACKING directory.
Release timeline:
https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/CoreTorReleases