5.4-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro viro@zeniv.linux.org.uk
[ Upstream commit 12f147ddd6de7382dad54812e65f3f08d05809fc ]
Ensure that propagation settings can only be changed for mounts located in the caller's mount namespace. This change aligns permission checking with the rest of mount(2).
Reviewed-by: Christian Brauner brauner@kernel.org Fixes: 07b20889e305 ("beginning of the shared-subtree proper") Reported-by: "Orlando, Noah" Noah.Orlando@deshaw.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/namespace.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/namespace.c b/fs/namespace.c index a5cb608778b1e..8a35144897686 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2246,6 +2246,10 @@ static int do_change_type(struct path *path, int ms_flags) return -EINVAL;
namespace_lock(); + if (!check_mnt(mnt)) { + err = -EINVAL; + goto out_unlock; + } if (type == MS_SHARED) { err = invent_group_ids(mnt, recurse); if (err)