CVE-2026-74729soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

Official description

In the Linux kernel, the following vulnerability has been resolved: soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read put_fifo_with_discard() acts as both producer and consumer on the kfifo: it calls kfifo_skip() (advances out) and kfifo_put() (advances in) from the IRQ handler without synchronizing with snoop_file_read(), which also consumes via kfifo_to_user(). On SMP systems this concurrent access can leave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp to (in - out) is ineffective and kfifo_copy_to_user() can attempt a copy_to_user() past the kmalloc-2k backing store: usercopy: Kernel memory exposure attempt detected from SLUB object 'kmalloc-2k' (offset 0, size 2049)! kernel BUG at mm/usercopy.c! Call trace: usercopy_abort __check_heap_object __check_object_size kfifo_copy_to_user __kfifo_to_user snoop_file_read vfs_read Serialize kfifo access with a per-channel spinlock shared between the IRQ handler (producer) and the file reader (consumer). Annotate @fifo with __guarded_by(&lock) and opt the driver into context analysis so the compiler enforces that all fifo access holds the lock.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/f62afe827c52c300c64715631e6ac9e576c5112d
• https://git.kernel.org/stable/c/b87c0d24386ed5106feac12034fe09d893ccb469
• https://git.kernel.org/stable/c/afe2527eae0b51d5e8ddd77293afab3a5a1311a4
• https://git.kernel.org/stable/c/868c478abce858135db3eb65548a577e4b6747ac
• https://git.kernel.org/stable/c/131ab677b03349a5ae48da8722ec7075b37ec66e
• https://git.kernel.org/stable/c/1acef6d85bfd98bd9dfe1f08bffa397a4dda8a6f