[PATCH v6 4/7] proc: allow access in init userns for map_files with CAP_CHECKPOINT_RESTORE
From: Adrian Reber <hidden>
Date: 2020-07-19 10:06:10
Also in:
linux-fsdevel, lkml, selinux
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
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. Signed-off-by: Adrian Reber <redacted> Signed-off-by: Nicolas Viennot <redacted> Reviewed-by: Cyrill Gorcunov <redacted> --- 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 65893686d1f1..b824a8c89011 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c@@ -2194,16 +2194,16 @@ 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);
--
2.26.2