From: Elizabeth Figura Date: Thu, 20 Feb 2025 19:23:34 +0000 (-0600) Subject: ntsync: Check wait count based on byte size. X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=92527e473911b835c2c18b0c55c337c33e85ff00;p=users%2Fdwmw2%2Flinux.git ntsync: Check wait count based on byte size. GCC versions below 13 incorrectly detect the copy size as being static and too small to fit in the "fds" array. Work around this by explicitly calculating the size and returning EINVAL based on that, instead of based on the object count. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202502072019.LYoCR9bF-lkp@intel.com/ Suggested-by: Arnd Bergmann Signed-off-by: Elizabeth Figura -- Suggested-by as per Arnd's request, but the only thing I changed was preserving array_size() [as noted by Geert in the linked thread]. I tested and found no regressions. v2: Add missing sign-off Link: https://lore.kernel.org/r/20250220192334.549167-1-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 0b4e56d59b3da..999026a1ae048 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -873,6 +873,7 @@ static int setup_wait(struct ntsync_device *dev, { int fds[NTSYNC_MAX_WAIT_COUNT + 1]; const __u32 count = args->count; + size_t size = array_size(count, sizeof(fds[0])); struct ntsync_q *q; __u32 total_count; __u32 i, j; @@ -880,15 +881,14 @@ static int setup_wait(struct ntsync_device *dev, if (args->pad || (args->flags & ~NTSYNC_WAIT_REALTIME)) return -EINVAL; - if (args->count > NTSYNC_MAX_WAIT_COUNT) + if (size >= sizeof(fds)) return -EINVAL; total_count = count; if (args->alert) total_count++; - if (copy_from_user(fds, u64_to_user_ptr(args->objs), - array_size(count, sizeof(*fds)))) + if (copy_from_user(fds, u64_to_user_ptr(args->objs), size)) return -EFAULT; if (args->alert) fds[count] = args->alert;