CVE-2026-68213

In the Linux kernel, the following vulnerability has been resolved:

media: rtl2832_sdr: Return queued buffers on start_streaming() failure

The vb2 framework hands buffers to the driver via buf_queue() before calling start_streaming(). If start_streaming() returns an error without first returning those buffers via vb2_buffer_done(), vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued buffers leak.

rtl2832_sdr_start_streaming() had multiple error paths that hit this trap: two direct early returns (-ENODEV, -ERESTARTSYS), plus six goto err paths covering subdev s_power, tuner setup, ADC setup, stream-buffer allocation, urb allocation, and urb submission failures. None of them returned the queued buffers.

The original function had no distinct success exit and fell straight through into the err label, which previously only did mutex_unlock and return ret. Adding queued-buffer cleanup at err must therefore be paired with an explicit success return; otherwise every successful start would also drain the buffer queue and kill streaming. Add that success return, then add rtl2832_sdr_cleanup_queued_bufs() at the err label and before each early return.

The cleanup helper takes a vb2_buffer_state argument so that the start_streaming error paths can pass VB2_BUF_STATE_QUEUED (as expected by userspace on start_streaming failure) while stop_streaming keeps its existing VB2_BUF_STATE_ERROR semantics.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb (media: uvcvideo: Return queued buffers on start_streaming() failure).

The err label still does not roll back power_ctrl(), frontend_ctrl(), the POWER_ON flag, or stream/URB allocations that may have happened before the failing step. Those are pre-existing leaks of a different class and are not addressed here.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/0b08c0403cf672a121ace4eff647a9b240bd4e1b
• https://git.kernel.org/stable/c/33ca0aab6f4bd90921fc1395478f38f72c4d19af
• https://git.kernel.org/stable/c/465dc8e71d2db2ed603e749fa71392bcdccf07eb
• https://git.kernel.org/stable/c/772f2550fe32357557d3b2f88e02f7cf477f0789
• https://git.kernel.org/stable/c/894e83509c66910112b9eaeaa8cd66cd9806db91
• https://git.kernel.org/stable/c/a248273f8af6e630a03e823274385725974009b5
• https://git.kernel.org/stable/c/fc0b18782aab4e35078efe72863df8eab46560a8
• https://git.kernel.org/stable/c/fd1e11fc3849169285e48b2d4ec441614ad2ea74