From b00e9baa00788cd2fd8e09c228d48e1902c93dd6 Mon Sep 17 00:00:00 2001 From: Adrian Reber Date: Sun, 19 Jul 2020 12:04:14 +0200 Subject: [PATCH] UPSTREAM: proc: allow access in init userns for map_files with CAP_CHECKPOINT_RESTORE Opening files in /proc/pid/map_files when the current user is CAP_CHECKPOINT_RESTORE capable in the root namespace is useful for checkpointing and restoring to recover files that are unreachable via the file system such as deleted files, or memfd files. Change-Id: I6ec3846f81a5208b66ef41e00229b7535e1e6668 Signed-off-by: Adrian Reber Signed-off-by: Nicolas Viennot Reviewed-by: Cyrill Gorcunov Reviewed-by: Serge Hallyn Link: https://lore.kernel.org/r/20200719100418.2112740-5-areber@redhat.com Signed-off-by: Christian Brauner Signed-off-by: ralph950412 Signed-off-by: rsuntk --- fs/proc/base.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 6c0b18ae383d..05879da0afb2 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2309,16 +2309,16 @@ struct map_files_info { }; /* - * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the - * symlinks may be used to bypass permissions on ancestor directories in the - * path to the file in question. + * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due + * to concerns about how the symlinks may be used to bypass permissions on + * ancestor directories in the path to the file in question. */ static const char * proc_map_files_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { - if (!capable(CAP_SYS_ADMIN)) + if (!checkpoint_restore_ns_capable(&init_user_ns)) return ERR_PTR(-EPERM); return proc_pid_get_link(dentry, inode, done);