The do_remount function in fs/namespace.c in the Linux kernel through 3.16.1 does not maintain the MNT_LOCK_READONLY bit across a remount of a bind mount, which allows local users to bypass an intended read-only restriction and defeat certain sandbox protection mechanisms via a "mount -o remount" command within a user namespace.
| Software | From | Fixed in |
|---|---|---|
| canonical / ubuntu_linux | 12.04 | 12.04.x |
| canonical / ubuntu_linux | 14.04 | 14.04.x |
| linux / linux_kernel | 3.13 | 3.14.19 |
| linux / linux_kernel | 3.15 | 3.16.3 |
| linux / linux_kernel | 3.11 | 3.12.27 |
| linux / linux_kernel | 3.8 | 3.10.55 |