| Message ID | 1449070821-73820-3-git-send-email-seth.forshee@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Dec 02, 2015 at 09:40:02AM -0600, Seth Forshee wrote: > Unprivileged users should not be able to mount block devices when > they lack sufficient privileges towards the block device inode. > Update blkdev_get_by_path() 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> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> > --- > fs/block_dev.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 3ebbde85d898..4fdb6ab59816 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -1424,9 +1424,14 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, > void *holder) > { > struct block_device *bdev; > + int perm = 0; > int err; > > - bdev = lookup_bdev(path, 0); > + if (mode & FMODE_READ) > + perm |= MAY_READ; > + if (mode & FMODE_WRITE) > + perm |= MAY_WRITE; > + bdev = lookup_bdev(path, perm); > if (IS_ERR(bdev)) > return bdev; > > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/block_dev.c b/fs/block_dev.c index 3ebbde85d898..4fdb6ab59816 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1424,9 +1424,14 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, void *holder) { struct block_device *bdev; + int perm = 0; int err; - bdev = lookup_bdev(path, 0); + if (mode & FMODE_READ) + perm |= MAY_READ; + if (mode & FMODE_WRITE) + perm |= MAY_WRITE; + bdev = lookup_bdev(path, perm); if (IS_ERR(bdev)) return bdev;
Unprivileged users should not be able to mount block devices when they lack sufficient privileges towards the block device inode. Update blkdev_get_by_path() 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> --- fs/block_dev.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)