Description of problem: The existing [btrfs] code would have allowed you to clone a file that was only open for writing. Not an expected behaviour. Upstream commit: http://git.kernel.org/linus/5dc6416414fb3ec6e2825fd4d20c8bf1d7fe0395 Reference: https://btrfs.wiki.kernel.org/index.php/Main_Page The kernel in Red Hat Enterprise Linux 6 has support for Btrfs by default. Acknowledgements: Red Hat would like to thank Dan Rosenberg for responsibly reporting this issue.
Statement: Not vulnerable. This issue did not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 3, 4, 5 and Red Hat Enterprise MRG as they did not include support for Btrfs, a new copy on write filesystem.
Created attachment 414994 [details] exploit.c The steps to reproduce the issue and exploit.c were made publicly available in: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/579585 $ dd if=/dev/zero of=fs.iso bs=1M count=500 $ losetup /dev/loop7 fs.iso $ mkfs.btrfs /dev/loop7 $ mkdir mountpoint $ mount /dev/loop7 mountpoint $ cd mountpoint $ echo "This is a write-only file" > target $ chmod 200 target $ ./exploit target output $ cat output This is a write-only file
kernel-2.6.33.5-112.fc13 has been submitted as an update for Fedora 13. http://admin.fedoraproject.org/updates/kernel-2.6.33.5-112.fc13
kernel-2.6.32.14-127.fc12 has been submitted as an update for Fedora 12. http://admin.fedoraproject.org/updates/kernel-2.6.32.14-127.fc12
kernel-2.6.33.5-112.fc13 has been pushed to the Fedora 13 stable repository. If problems still persist, please make note of it in this bug report.
kernel-2.6.32.14-127.fc12 has been pushed to the Fedora 12 stable repository. If problems still persist, please make note of it in this bug report.