In the Linux kernel, there is a vulnerability in the Universal Video Class (UVC) video driver that could lead to out-of-bounds writes. This vulnerability has been assigned the CVE identifier CVE-2024-53104. In this post, we'll dive into the details of this exploit, understand the original issue, and look at the solution provided by the Linux kernel developers.
Original References
- [Patchwork: Linux-Media] Resolution of Vulnerability: Link
- [Linux Kernel Git Commit] Fixing vulnerability: Link
The Issue: UVC_VS_UNDEFINED Frame Type
The vulnerability lies in the handling of UVC_VS_UNDEFINED frame types inside the "uvc_parse_format" function in the Linux kernel's UVC driver. The frames buffer size in "uvc_parse_streaming" was not calculated correctly, as it needs to take into account the UVC_VS_UNDEFINED frame types.
The Code Snippet with the Issue
static int uvc_parse_format(struct uvc_device *dev,
struct uvc_streaming *stream,
struct uvc_format *format, __u8 *buffer, int buflen)
{
...
/* Skip frames of type UVC_VS_UNDEFINED */
if (buffer[2] == UVC_VS_UNDEFINED)
continue;
...
}
This previously unhandled frame type could potentially lead to buffer overflow issues, causing crashes and other undesirable behavior.
Exploit Details
When parsing video frames, the "uvc_parse_streaming" function calculates the size required for the frames buffer. But as mentioned earlier, it was not considering the UVC_VS_UNDEFINED frame type, which could lead to the buffer size being smaller than what is actually needed. In this case, when the UVC_VS_UNDEFINED frame types appear in the stream, it may result in out-of-bounds writes, which could then lead to memory corruption, crashes, or even allow attackers to execute arbitrary code.
The Fix
The Linux kernel developers have resolved this vulnerability by adding an additional check in the "uvc_parse_format" function to skip the frames of type UVC_VS_UNDEFINED. This ensures that the frames buffer size is calculated correctly and does not lead to out-of-bounds write issues.
The Code Snippet with the Fix
static int uvc_parse_format(struct uvc_device *dev,
struct uvc_streaming *stream,
struct uvc_format *format, __u8 *buffer, int buflen)
{
...
/* Skip frames of type UVC_VS_UNDEFINED */
if (buffer[2] == UVC_VS_UNDEFINED)
continue;
...
}
Conclusion
With the CVE-2024-53104 vulnerability fixed, the Linux kernel's UVC video driver handles video frame parsing more securely, preventing potential exploits that could lead to out-of-bounds writes. It's crucial for users and admins to keep their systems up-to-date with the latest Linux kernel patches to ensure the highest level of security and stability.
Timeline
Published on: 12/02/2024 08:15:08 UTC
Last modified on: 01/20/2025 06:19:37 UTC