diff options
Diffstat (limited to 'userns-Document-what-the-invariant-required-for-safe.patch')
| -rw-r--r-- | userns-Document-what-the-invariant-required-for-safe.patch | 48 |
1 files changed, 0 insertions, 48 deletions
diff --git a/userns-Document-what-the-invariant-required-for-safe.patch b/userns-Document-what-the-invariant-required-for-safe.patch deleted file mode 100644 index c364b2bc..00000000 --- a/userns-Document-what-the-invariant-required-for-safe.patch +++ /dev/null @@ -1,48 +0,0 @@ -From: "Eric W. Biederman" <ebiederm@xmission.com> -Date: Fri, 5 Dec 2014 17:51:47 -0600 -Subject: [PATCH] userns: Document what the invariant required for safe - unprivileged mappings. - -The rule is simple. Don't allow anything that wouldn't be allowed -without unprivileged mappings. - -It was previously overlooked that establishing gid mappings would -allow dropping groups and potentially gaining permission to files and -directories that had lesser permissions for a specific group than for -all other users. - -This is the rule needed to fix CVE-2014-8989 and prevent any other -security issues with new_idmap_permitted. - -The reason for this rule is that the unix permission model is old and -there are programs out there somewhere that take advantage of every -little corner of it. So allowing a uid or gid mapping to be -established without privielge that would allow anything that would not -be allowed without that mapping will result in expectations from some -code somewhere being violated. Violated expectations about the -behavior of the OS is a long way to say a security issue. - -Cc: stable@vger.kernel.org -Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> ---- - kernel/user_namespace.c | 4 +++- - 1 file changed, 3 insertions(+), 1 deletion(-) - -diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c -index aa312b0dc3ec..b99c862a2e3f 100644 ---- a/kernel/user_namespace.c -+++ b/kernel/user_namespace.c -@@ -812,7 +812,9 @@ static bool new_idmap_permitted(const struct file *file, - struct user_namespace *ns, int cap_setid, - struct uid_gid_map *new_map) - { -- /* Allow mapping to your own filesystem ids */ -+ /* Don't allow mappings that would allow anything that wouldn't -+ * be allowed without the establishment of unprivileged mappings. -+ */ - if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1)) { - u32 id = new_map->extent[0].lower_first; - if (cap_setid == CAP_SETUID) { --- -2.1.0 - |