From: Daniel Borkmann Date: Sun, 22 May 2016 21:16:18 +0000 (+0200) Subject: bpf, inode: disallow userns mounts X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=612bacad78ba6d0a91166fc4487af114bac172a8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git bpf, inode: disallow userns mounts Follow-up to commit e27f4a942a0e ("bpf: Use mount_nodev not mount_ns to mount the bpf filesystem"), which removes the FS_USERNS_MOUNT flag. The original idea was to have a per mountns instance instead of a single global fs instance, but that didn't work out and we had to switch to mount_nodev() model. The intent of that middle ground was that we avoid users who don't play nice to create endless instances of bpf fs which are difficult to control and discover from an admin point of view, but at the same time it would have allowed us to be more flexible with regard to namespaces. Therefore, since we now did the switch to mount_nodev() as a fix where individual instances are created, we also need to remove userns mount flag along with it to avoid running into mentioned situation. I don't expect any breakage at this early point in time with removing the flag and we can revisit this later should the requirement for this come up with future users. This and commit e27f4a942a0e have been split to facilitate tracking should any of them run into the unlikely case of causing a regression. Fixes: b2197755b263 ("bpf: add support for persistent maps/progs") Signed-off-by: Daniel Borkmann Acked-by: Hannes Frederic Sowa Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 04be7021f848..318858edb1cd 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -365,7 +365,6 @@ static struct file_system_type bpf_fs_type = { .name = "bpf", .mount = bpf_mount, .kill_sb = kill_litter_super, - .fs_flags = FS_USERNS_MOUNT, }; MODULE_ALIAS_FS("bpf");