pacman before 5.1.3 allows directory traversal when installing a remote package via a specified URL "pacman -U <url>" due to an unsanitized file name received from a Content-Disposition header. pacman renames the downloaded package file to match the name given in this header. However, pacman did not sanitize this name, which may contain slashes, before calling rename(). A malicious server (or a network MitM if downloading over HTTP) can send a Content-Disposition header to make pacman place the file anywhere in the filesystem, potentially leading to arbitrary root code execution. Notably, this bypasses pacman's package signature checking. This occurs in curl_download_internal in lib/libalpm/dload.c.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
| Link | Tags |
|---|---|
| https://git.archlinux.org/pacman.git/commit/?id=d197d8ab82cf10650487518fb968067897a12775 | patch mailing list third party advisory |
| https://git.archlinux.org/pacman.git/commit/?h=release/5.1.x&id=1bf767234363f7ad5933af3f7ce267c123017bde | third party advisory mailing list |
| https://git.archlinux.org/pacman.git/commit/?id=9702703633bec2c007730006de2aeec8587dfc84 | patch mailing list third party advisory |