On 22/06/2023 16:13, Benjamin Gaignard wrote:

Le 22/06/2023 à 16:11, Dan Carpenter a écrit :

quoted

On Thu, Jun 22, 2023 at 03:13:41PM +0200, Benjamin Gaignard wrote:

quoted

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index f1ff7af34a9f..86e1e926fa45 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c

@@ -455,9 +455,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,

      struct vb2_buffer *vb;
      int ret;
  -    /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
+    /* Ensure that q->num_buffers + num_buffers is UINT_MAX */
      num_buffers = min_t(unsigned int, num_buffers,
-                VB2_MAX_FRAME - q->num_buffers);
+                UINT_MAX - q->num_buffers);
        for (buffer = 0; buffer < num_buffers; ++buffer) {
          /* Allocate vb2 buffer structures */

Ah...  Here's one of the integer overflow bugs I was talking about.  The
__vb2_queue_alloc() function returns an int so if num_buffers goes over
INT_MAX we are hosed.

I will limit it to:
#define VB2_QUEUE_MAX_BUFFERS  (INT_MAX & PAGE_MASK)  /* The mask prevents 85% of integer overflows */
as you have suggest it.

IMHO INT_MAX is way overkill. How about (1U << 20)? I would like some sort of
sanity check here. 1048576 buffers of 640x480 and 4 bytes per pixel is 1.2 TB.

Since a TB of memory is doable these days, I think this is a reasonable
value for MAX_BUFFERS without allowing just anything.

An alternative is to make this a kernel config.

Regards,

	Hans

That will be in version 4.

Thanks,
Benjamin

quoted

regards,
dan carpenter

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