On Fri, Dec 22, 2017 at 03:32:26PM +0100, Dongsu Park wrote: > From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > > 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. > > Patch v3 is available: https://patchwork.kernel.org/patch/7640011/ > > Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > Signed-off-by: Dongsu Park <dongsu@xxxxxxxxxx> Acked-by: Serge Hallyn <serge@xxxxxxxxxx> > --- > drivers/mtd/mtdsuper.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c > index 4a4d40c0..3c8734f3 100644 > --- a/drivers/mtd/mtdsuper.c > +++ b/drivers/mtd/mtdsuper.c > @@ -129,6 +129,7 @@ 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; > > @@ -180,7 +181,10 @@ 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); > -- > 2.13.6 > > _______________________________________________ > Containers mailing list > Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/containers _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
