From dbc48c8f41c208082cfa95e973560134489e3309 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 24 Jun 2024 23:10:59 +0300 Subject: perf: Prevent passing zero nr_pages to rb_alloc_aux() nr_pages is unsigned long but gets passed to rb_alloc_aux() as an int, and is stored as an int. Only power-of-2 values are accepted, so if nr_pages is a 64_bit value, it will be passed to rb_alloc_aux() as zero. That is not ideal because: 1. the value is incorrect 2. rb_alloc_aux() is at risk of misbehaving, although it manages to return -ENOMEM in that case, it is a result of passing zero to get_order() even though the get_order() result is documented to be undefined in that case. Fix by simply validating the maximum supported value in the first place. Use -ENOMEM error code for consistency with the current error code that is returned in that case. Fixes: 45bfb2e50471 ("perf: Add AUX area to ring buffer for raw data streams") Signed-off-by: Adrian Hunter Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20240624201101.60186-6-adrian.hunter@intel.com --- kernel/events/core.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/events') diff --git a/kernel/events/core.c b/kernel/events/core.c index 6b0a66ed2ae3..e70d3dd65a13 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6496,6 +6496,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) return -EINVAL; nr_pages = vma_size / PAGE_SIZE; + if (nr_pages > INT_MAX) + return -ENOMEM; mutex_lock(&event->mmap_mutex); ret = -EINVAL; -- cgit v1.2.3