@@ -125,6 +125,7 @@ struct dentry *mount_mtd(struct file_system_type *fs_type, int flags,
#ifdef CONFIG_BLOCK
struct block_device *bdev;
int ret, major;
+ int perm;
#endif
int mtdnr;
@@ -176,7 +177,10 @@ struct dentry *mount_mtd(struct file_system_type *fs_type, int flags,
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
- bdev = lookup_bdev(dev_name, 0);
+ perm = MAY_READ;
+ if (!(flags & MS_RDONLY))
+ perm |= MAY_WRITE;
+ bdev = lookup_bdev(dev_name, perm);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
pr_debug("MTDSB: lookup_bdev() returned %d\n", ret);
Unprivileged users should not be able to mount mtd block devices when they lack sufficient privileges towards the block device inode. Update mount_mtd() to validate that the user has the required access to the inode at the specified path. The check will be skipped for CAP_SYS_ADMIN, so privileged mounts will continue working as before. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> --- drivers/mtd/mtdsuper.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)