4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
[ 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@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240624201101.60186-6-adrian.hunter@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
--
2.43.0
