Vulnerabilidades de Nixos

Nix before 2.35.3 and Lix before 2.95.4 allow privilege escalation via a repair operation because it could destroy and then replace a store path before content verification.

Nix before 2.35.3 and Lix before 2.95.4 have an integer overflow and resultant out-of-bounds write when evaluating untrusted expressions because list allocation is mishandled.

An issue was discovered in Nix before 2.34.7 and Lix before 2.95.2. Unbounded recursion in the NAR (Nix Archive) parser could lead to a stack-to-heap overflow when the parser is run on a coroutine stack. The stack is allocated without a guard page, which means that a stack overflow could overwrite memory on the heap and could allow arbitrary code execution as the Nix daemon (run as root in multi-user installations) if ASLR hardening is bypassed. This can be exploited by all users able to connect to the daemon (e.g., in Nix, this is configurable via the allowed-users setting, defaulting to all users). The fixed versions are 2.34.7, 2.33.6, 2.32.8, 2.31.5, 2.30.5, 2.29.4, and 2.28.7 for Nix (introduced in 2.24.4); and 2.95.2, 2.94.2, and 2.93.4 for Lix (introduced in 2.93.0).

In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Revert to operating out-of-place This mostly reverts commit 72548b093ee3 except for the copying of the associated data. There is no benefit in operating in-place in algif_aead since the source and destination come from different mappings. Get rid of all the complexity added for in-place operation and just copy the AD directly.

Nix is a package manager for Linux and other Unix systems. A bug in the fix for CVE-2024-27297 allowed for arbitrary overwrites of files writable by the Nix process orchestrating the builds (typically the Nix daemon running as root in multi-user installations) by following symlinks during fixed-output derivation output registration. This affects sandboxed Linux builds - sandboxed macOS builds are unaffected. The location of the temporary output used for the output copy was located inside the build chroot. A symlink, pointing to an arbitrary location in the filesystem, could be created by the derivation builder at that path. During output registration, the Nix process (running in the host mount namespace) would follow that symlink and overwrite the destination with the derivation's output contents. In multi-user installations, this allows all users able to submit builds to the Nix daemon (allowed-users - defaulting to all users) to gain root privileges by modifying sensitive files. This vulnerability is fixed in 2.34.5, 2.33.4, 2.32.7, 2.31.4, 2.30.4, 2.29.3, and 2.28.6.

Tandoor Recipes is a recipe manager than can be installed with the Nix package manager. Starting in version 23.05 and prior to version 26.05, when using the default configuration of Tandoor Recipes, specifically using SQLite and default `MEDIA_ROOT`, the full database file may be externally accessible, potentially on the Internet. The root cause is that the NixOS module configures the working directory of Tandoor Recipes, as well as the value of `MEDIA_ROOT`, to be `/var/lib/tandoor-recipes`. This causes Tandoor Recipes to create its `db.sqlite3` database file in the same directory as `MEDIA_ROOT` causing it to be accessible without authentication through HTTP like any other media file. This is the case when using `GUNICORN_MEDIA=1` or when using a web server like nginx to serve media files. NixOS 26.05 changes the default value of `MEDIA_ROOT` to a sub folder of the data directory. This only applies to configurations with `system.stateVersion` >= 26.05. For older configurations, one of the workarounds should be applied instead. NixOS 25.11 has received a backport of this patch, though it doesn't fix this vulnerability without user intervention. A recommended workaround is to move `MEDIA_ROOT` into a subdirectory. Non-recommended workarounds include switching to PostgreSQL or disallowing access to `db.sqlite3`.

A flaw was found in rsync which could be triggered when rsync compares file checksums. This flaw allows an attacker to manipulate the checksum length (s2length) to cause a comparison between a checksum and uninitialized memory and leak one byte of uninitialized stack data at a time.