In the Linux kernel, the following vulnerability has been resolved:
mips: sched: Fix CPUMASK_OFFSTACK memory corruption
This patch addresses a critical memory management flaw. When CONFIG_CPUMASK_OFFSTACK is enabled, cpumask_var_t is a pointer. Consequently, sizeof(new_mask) evaluates to the pointer size, causing copy_from_user() to clobber the mask pointer. Furthermore, the old logic performed copy_from_user() before allocating the mask.
Fix this by allocating new_mask first. To handle variable-sized user masks correctly, use cpumask_size() to truncate overly large user masks or pad undersized masks with zeros before copying the data directly into the allocated buffer.
References
- https://git.kernel.org/stable/c/15ba8053fe4162c933855f1676fb321cdb6251c7
- https://git.kernel.org/stable/c/1caee6e084a96ada94658f261ced377d85af3f03
- https://git.kernel.org/stable/c/3446ffb5d03c36f9ce88ede7ca5be319a2968d96
- https://git.kernel.org/stable/c/87a56c1e8e36d06ebe8640432f911538ded7827d
- https://git.kernel.org/stable/c/98e37db4a34d3af3fb2f4648295c25b5e40b20e3
- https://git.kernel.org/stable/c/a1dd41d00c57efb1fbc6f361c5f48c9d00cca51c
- https://git.kernel.org/stable/c/d20ee42f8226607b5693b2bc2f115ca2d270221a