4.19-stable review patch. If anyone has any objections, please let me know.
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From: Adrian Hunter adrian.hunter@intel.com
[ Upstream commit dbc48c8f41c208082cfa95e973560134489e3309 ]
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 adrian.hunter@intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/r/20240624201101.60186-6-adrian.hunter@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c index c7651c30eaabf..4f1b0fc2e74d2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5730,6 +5730,8 @@ 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;