| Message ID | 20230318085023.832510-1-zyytlz.wz@163.com |
|---|---|
| State | Accepted |
| Commit | 30cf57da176cca80f11df0d9b7f71581fe601389 |
| Headers | show |
| Series | media: saa7134: fix use after free bug in saa7134_finidev due to race condition | expand |
diff --git a/drivers/media/pci/saa7134/saa7134-ts.c b/drivers/media/pci/saa7134/saa7134-ts.c index 6a5053126237..437dbe5e75e2 100644 --- a/drivers/media/pci/saa7134/saa7134-ts.c +++ b/drivers/media/pci/saa7134/saa7134-ts.c @@ -300,6 +300,7 @@ int saa7134_ts_start(struct saa7134_dev *dev) int saa7134_ts_fini(struct saa7134_dev *dev) { + del_timer_sync(&dev->ts_q.timeout); saa7134_pgtable_free(dev->pci, &dev->ts_q.pt); return 0; } diff --git a/drivers/media/pci/saa7134/saa7134-vbi.c b/drivers/media/pci/saa7134/saa7134-vbi.c index 3f0b0933eed6..3e773690468b 100644 --- a/drivers/media/pci/saa7134/saa7134-vbi.c +++ b/drivers/media/pci/saa7134/saa7134-vbi.c @@ -185,6 +185,7 @@ int saa7134_vbi_init1(struct saa7134_dev *dev) int saa7134_vbi_fini(struct saa7134_dev *dev) { /* nothing */ + del_timer_sync(&dev->vbi_q.timeout); return 0; } diff --git a/drivers/media/pci/saa7134/saa7134-video.c b/drivers/media/pci/saa7134/saa7134-video.c index 4d8974c9fcc9..29124756a62b 100644 --- a/drivers/media/pci/saa7134/saa7134-video.c +++ b/drivers/media/pci/saa7134/saa7134-video.c @@ -2146,6 +2146,7 @@ int saa7134_video_init1(struct saa7134_dev *dev) void saa7134_video_fini(struct saa7134_dev *dev) { + del_timer_sync(&dev->video_q.timeout); /* free stuff */ saa7134_pgtable_free(dev->pci, &dev->video_q.pt); saa7134_pgtable_free(dev->pci, &dev->vbi_q.pt);
In saa7134_initdev, it will call saa7134_hwinit1. There are three function invoking here: saa7134_video_init1, saa7134_ts_init1 and saa7134_vbi_init1. All of them will init a timer with same function. Take saa7134_video_init1 as an example. It'll bound &dev->video_q.timeout with saa7134_buffer_timeout. In buffer_activate, the timer funtcion is started. If we remove the module or device which will call saa7134_finidev to make cleanup, there may be a unfinished work. The possible sequence is as follows, which will cause a typical UAF bug. Fix it by canceling the timer works accordingly before cleanup in saa7134_finidev. CPU0 CPU1 |saa7134_buffer_timeout saa7134_finidev | kfree(dev); | | | saa7134_buffer_next | //use dev Fixes: 1e7126b4a86a ("media: saa7134: Convert timers to use timer_setup()") Signed-off-by: Zheng Wang <zyytlz.wz@163.com> --- drivers/media/pci/saa7134/saa7134-ts.c | 1 + drivers/media/pci/saa7134/saa7134-vbi.c | 1 + drivers/media/pci/saa7134/saa7134-video.c | 1 + 3 files changed, 3 insertions(+)