| Message ID | 1600425151-27670-1-git-send-email-charante@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dmabuf: fix NULL pointer dereference in dma_buf_release() | expand |
Am 18.09.20 um 12:32 schrieb Charan Teja Reddy: > NULL pointer dereference is observed while exporting the dmabuf but > failed to allocate the 'struct file' which results into the dropping of > the allocated dentry corresponding to this file in the dmabuf fs, which > is ending up in dma_buf_release() and accessing the uninitialzed > dentry->d_fsdata. > > Call stack on 5.4 is below: > dma_buf_release+0x2c/0x254 drivers/dma-buf/dma-buf.c:88 > __dentry_kill+0x294/0x31c fs/dcache.c:584 > dentry_kill fs/dcache.c:673 [inline] > dput+0x250/0x380 fs/dcache.c:859 > path_put+0x24/0x40 fs/namei.c:485 > alloc_file_pseudo+0x1a4/0x200 fs/file_table.c:235 > dma_buf_getfile drivers/dma-buf/dma-buf.c:473 [inline] > dma_buf_export+0x25c/0x3ec drivers/dma-buf/dma-buf.c:585 > > Fix this by checking for the valid pointer in the dentry->d_fsdata. > > Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") > Cc: <stable@vger.kernel.org> [5.7+] > Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> Reviewed-by: Christian König <christian.koenig@amd.com> Going to pick this up for inclusion into drm-misc-next as well. > --- > drivers/dma-buf/dma-buf.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 58564d82..844967f 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -59,6 +59,8 @@ static void dma_buf_release(struct dentry *dentry) > struct dma_buf *dmabuf; > > dmabuf = dentry->d_fsdata; > + if (unlikely(!dmabuf)) > + return; > > BUG_ON(dmabuf->vmapping_counter); >
On Fri, Sep 18, 2020 at 01:16:16PM +0200, Christian König wrote: > Am 18.09.20 um 12:32 schrieb Charan Teja Reddy: > > NULL pointer dereference is observed while exporting the dmabuf but > > failed to allocate the 'struct file' which results into the dropping of > > the allocated dentry corresponding to this file in the dmabuf fs, which > > is ending up in dma_buf_release() and accessing the uninitialzed > > dentry->d_fsdata. > > > > Call stack on 5.4 is below: > > dma_buf_release+0x2c/0x254 drivers/dma-buf/dma-buf.c:88 > > __dentry_kill+0x294/0x31c fs/dcache.c:584 > > dentry_kill fs/dcache.c:673 [inline] > > dput+0x250/0x380 fs/dcache.c:859 > > path_put+0x24/0x40 fs/namei.c:485 > > alloc_file_pseudo+0x1a4/0x200 fs/file_table.c:235 > > dma_buf_getfile drivers/dma-buf/dma-buf.c:473 [inline] > > dma_buf_export+0x25c/0x3ec drivers/dma-buf/dma-buf.c:585 > > > > Fix this by checking for the valid pointer in the dentry->d_fsdata. > > > > Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") > > Cc: <stable@vger.kernel.org> [5.7+] > > Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> > > Reviewed-by: Christian König <christian.koenig@amd.com> > > Going to pick this up for inclusion into drm-misc-next as well. drm-misc-fixes since this is a bugfix that needs to be backported. -Daniel > > > --- > > drivers/dma-buf/dma-buf.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > index 58564d82..844967f 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -59,6 +59,8 @@ static void dma_buf_release(struct dentry *dentry) > > struct dma_buf *dmabuf; > > dmabuf = dentry->d_fsdata; > > + if (unlikely(!dmabuf)) > > + return; > > BUG_ON(dmabuf->vmapping_counter); > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 58564d82..844967f 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -59,6 +59,8 @@ static void dma_buf_release(struct dentry *dentry) struct dma_buf *dmabuf; dmabuf = dentry->d_fsdata; + if (unlikely(!dmabuf)) + return; BUG_ON(dmabuf->vmapping_counter);
NULL pointer dereference is observed while exporting the dmabuf but failed to allocate the 'struct file' which results into the dropping of the allocated dentry corresponding to this file in the dmabuf fs, which is ending up in dma_buf_release() and accessing the uninitialzed dentry->d_fsdata. Call stack on 5.4 is below: dma_buf_release+0x2c/0x254 drivers/dma-buf/dma-buf.c:88 __dentry_kill+0x294/0x31c fs/dcache.c:584 dentry_kill fs/dcache.c:673 [inline] dput+0x250/0x380 fs/dcache.c:859 path_put+0x24/0x40 fs/namei.c:485 alloc_file_pseudo+0x1a4/0x200 fs/file_table.c:235 dma_buf_getfile drivers/dma-buf/dma-buf.c:473 [inline] dma_buf_export+0x25c/0x3ec drivers/dma-buf/dma-buf.c:585 Fix this by checking for the valid pointer in the dentry->d_fsdata. Fixes: 4ab59c3c638c ("dma-buf: Move dma_buf_release() from fops to dentry_ops") Cc: <stable@vger.kernel.org> [5.7+] Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> --- drivers/dma-buf/dma-buf.c | 2 ++ 1 file changed, 2 insertions(+)