Hauke Mehrtens
d09134f6ed
The "name=value\0 ... \0\0" walk over the mmap()ed nvram used strchr()
and strlen() without a bound, so an nvram without the terminating
double NUL made it run past the end of the mapping.
Search with memchr() up to the length from the nvram header, or up to
the end of the mapping when that length does not fit, so a broken
header is still readable. A variable that is not terminated in this
area ends the parsing.
Map a regular file, like the /tmp staging file, only as far as it is
backed, rounded down to 4 bytes for the padding in nvram_commit(),
instead of the partition size which raised SIGBUS. Only search the
start of a mapping smaller than NVRAM_MIN_SPACE for the magic instead
of underflowing the loop boundary; bcm47xxpart creates such nvram
partitions on flashes with 4 KiB erase blocks.
"nvram info" clamps the header length before the CRC8, it read beyond
the mapping or underflowed into a 4 GB read before.
This is reachable with a crafted nvram partition or staging file, on
bcm47xx the nvram partition is also parsed while booting.
Reported by @tonoyx91 and @0xROI.
Link: https://github.com/openwrt/openwrt/security/advisories/GHSA-5m25-qmhm-crr4
Fixes: 400c1a7fbf ("Add unvram, a nvram manipulation tool suitable for brcm-2.4 and bcm47xx platforms")
Assisted-by: Claude:claude-opus-5
Link: https://github.com/openwrt/openwrt/pull/25240
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
OpenWrt Project is a Linux operating system targeting embedded devices. Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the application selection and configuration provided by the vendor and allows you to customize the device through the use of packages to suit any application. For developers, OpenWrt is the framework to build an application without having to build a complete firmware around it; for users this means the ability for full customization, to use the device in ways never envisioned.
Sunshine!
Download
Built firmware images are available for many architectures and come with a package selection to be used as WiFi home router. To quickly find a factory image usable to migrate from a vendor stock firmware to OpenWrt, try the Firmware Selector.
If your device is supported, please follow the Info link to see install instructions or consult the support resources listed below.
An advanced user may require additional or specific package. (Toolchain, SDK, ...) For everything else than simple firmware download, try the wiki download page:
Development
To build your own firmware you need a GNU/Linux, BSD or macOS system (case sensitive filesystem required). Cygwin is unsupported because of the lack of a case sensitive file system.
Requirements
You need the following tools to compile OpenWrt, the package names vary between distributions. A complete list with distribution specific packages is found in the Build System Setup documentation.
binutils bzip2 diff find flex gawk gcc-6+ getopt grep install libc-dev libz-dev
make4.1+ perl python3.8+ rsync subversion unzip which
Quickstart
-
Run
./scripts/feeds update -ato obtain all the latest package definitions defined in feeds.conf / feeds.conf.default -
Run
./scripts/feeds install -ato install symlinks for all obtained packages into package/feeds/ -
Run
make menuconfigto select your preferred configuration for the toolchain, target system & firmware packages. -
Run
maketo build your firmware. This will download all sources, build the cross-compile toolchain and then cross-compile the GNU/Linux kernel & all chosen applications for your target system.
Related Repositories
The main repository uses multiple sub-repositories to manage packages of
different categories. All packages are installed via the OpenWrt package
manager called opkg. If you're looking to develop the web interface or port
packages to OpenWrt, please find the fitting repository below.
-
LuCI Web Interface: Modern and modular interface to control the device via a web browser.
-
OpenWrt Packages: Community repository of ported packages.
-
OpenWrt Routing: Packages specifically focused on (mesh) routing.
-
OpenWrt Video: Packages specifically focused on display servers and clients (Xorg and Wayland).
Support Information
For a list of supported devices see the OpenWrt Hardware Database
Documentation
Support Community
- Forum: For usage, projects, discussions and hardware advise.
- Support Chat: Channel
#openwrton oftc.net.
Developer Community
- Bug Reports: Report bugs in OpenWrt
- Dev Mailing List: Send patches
- Dev Chat: Channel
#openwrt-develon oftc.net.
License
OpenWrt is licensed under GPL-2.0