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authorLinus Torvalds <torvalds@linux-foundation.org>2013-04-18 18:09:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-18 18:09:12 -0700
commit6835039d7ed618bbac0c8c18d62d3e030b162d37 (patch)
tree840f453cebdb1a908d3b40dfbcb9e42699636055
parenta86d52667d8eda5de39393ce737794403bdce1eb (diff)
parent41c21e351e79004dbb4efa4bc14a53a7e0af38c5 (diff)
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Merge branch 'userns-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux
Pull user-namespace fixes from Andy Lutomirski. * 'userns-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux: userns: Changing any namespace id mappings should require privileges userns: Check uid_map's opener's fsuid, not the current fsuid userns: Don't let unprivileged users trick privileged users into setting the id_map
-rw-r--r--kernel/user_namespace.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a54f26f82eb2..e134d8f365dd 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -25,7 +25,8 @@
static struct kmem_cache *user_ns_cachep __read_mostly;
-static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
+static bool new_idmap_permitted(const struct file *file,
+ struct user_namespace *ns, int cap_setid,
struct uid_gid_map *map);
static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
@@ -612,10 +613,10 @@ 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 */
@@ -700,7 +701,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
ret = -EPERM;
/* Validate the user is allowed to use user id's mapped to. */
- if (!new_idmap_permitted(ns, cap_setid, &new_map))
+ if (!new_idmap_permitted(file, ns, cap_setid, &new_map))
goto out;
/* Map the lower ids from the parent user namespace to the
@@ -787,7 +788,8 @@ ssize_t proc_projid_map_write(struct file *file, const char __user *buf, size_t
&ns->projid_map, &ns->parent->projid_map);
}
-static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
+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 */
@@ -795,12 +797,12 @@ static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
u32 id = new_map->extent[0].lower_first;
if (cap_setid == CAP_SETUID) {
kuid_t uid = make_kuid(ns->parent, id);
- if (uid_eq(uid, current_fsuid()))
+ if (uid_eq(uid, file->f_cred->fsuid))
return true;
}
else if (cap_setid == CAP_SETGID) {
kgid_t gid = make_kgid(ns->parent, id);
- if (gid_eq(gid, current_fsgid()))
+ if (gid_eq(gid, file->f_cred->fsgid))
return true;
}
}
@@ -811,8 +813,10 @@ static bool new_idmap_permitted(struct user_namespace *ns, int cap_setid,
/* Allow the specified ids if we have the appropriate capability
* (CAP_SETUID or CAP_SETGID) over the parent user namespace.
+ * And the opener of the id file also had the approprpiate capability.
*/
- if (ns_capable(ns->parent, cap_setid))
+ if (ns_capable(ns->parent, cap_setid) &&
+ file_ns_capable(file, ns->parent, cap_setid))
return true;
return false;