Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
erofs: verify metadata accesses for file-backed mounts
For file-backed mounts, metadata is fetched via the page cache of
backing inodes to avoid double caching and redundant copy ops out
of RO uptodate folios, which is used by Android APEXes, ComposeFS,
containerd. However, rw_verify_area() was missing prior to
metadata accesses.
Similar to vfs_iocb_iter_read(), fix this by:
- Enabling fanotify pre-content hooks on metadata accesses;
- security_file_permission() for security modules.
Verified that fanotify pre-content hooks now works correctly.
Fixes: fb176750266a ("erofs: add file-backed mount support")
Acked-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Chunhai Guo <guochunhai@vivo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
+14
+14
fs/erofs/data.c
+14
fs/erofs/data.c
···
30
30
{
31
31
pgoff_t index = (buf->off + offset) >> PAGE_SHIFT;
32
32
struct folio *folio = NULL;
33
+
loff_t fpos;
34
+
int err;
35
+
36
+
/*
37
+
* Metadata access for file-backed mounts reuses page cache of backing
38
+
* fs inodes (only folio data will be needed) to prevent double caching.
39
+
* However, the data access range must be verified here in advance.
40
+
*/
41
+
if (buf->file) {
42
+
fpos = index << PAGE_SHIFT;
43
+
err = rw_verify_area(READ, buf->file, &fpos, PAGE_SIZE);
44
+
if (err < 0)
45
+
return ERR_PTR(err);
46
+
}
33
47
34
48
if (buf->page) {
35
49
folio = page_folio(buf->page);