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authorAndy Lutomirski <luto@amacapital.net>2013-04-14 11:44:04 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-25 12:51:23 -0700
commit37ed4a3f3bb107bfb307610b9ab2b87db03df3a6 (patch)
tree4217265b5f8a960f5f8c041e616f373959481b64
parentbe4c1b46075d42cbd82bc0d1e833dc4de052ae85 (diff)
downloadlinux-linaro-stable-37ed4a3f3bb107bfb307610b9ab2b87db03df3a6.tar.gz
userns: Changing any namespace id mappings should require privileges
commit 41c21e351e79004dbb4efa4bc14a53a7e0af38c5 upstream. Changing uid/gid/projid mappings doesn't change your id within the namespace; it reconfigures the namespace. Unprivileged programs should *not* be able to write these files. (We're also checking the privileges on the wrong task.) Given the write-once nature of these files and the other security checks, this is likely impossible to usefully exploit. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/user_namespace.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index fdf40d6cf8a4..f359dc7fb8c5 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -576,10 +576,10 @@ static ssize_t map_write(struct file *file, const char __user *buf,
if (map->nr_extents != 0)
goto out;
- /* Require the appropriate privilege CAP_SETUID or CAP_SETGID
- * over the user namespace in order to set the id mapping.
+ /*
+ * Adjusting namespace settings requires capabilities on the target.
*/
- if (cap_valid(cap_setid) && !ns_capable(ns, cap_setid))
+ if (cap_valid(cap_setid) && !file_ns_capable(file, ns, CAP_SYS_ADMIN))
goto out;
/* Get a buffer */