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authorSerge E. Hallyn <serge@hallyn.com>2011-03-23 16:43:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-23 19:47:08 -0700
commite795b71799ff0b27365020c9ddaa25d0d83f99c8 (patch)
treef3b628c2366f181380a8fbcd490910eb086a7b8e /fs/inode.c
parentb0e77598f87107001a00b8a4ece9c95e4254ccc4 (diff)
userns: userns: check user namespace for task->file uid equivalence checks
Cheat for now and say all files belong to init_user_ns. Next step will be to let superblocks belong to a user_ns, and derive inode_userns(inode) from inode->i_sb->s_user_ns. Finally we'll introduce more flexible arrangements. Changelog: Feb 15: make is_owner_or_cap take const struct inode Feb 23: make is_owner_or_cap bool [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/inode.c')
-rw-r--r--fs/inode.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 16fefd373fc..a21d5a938a1 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -25,6 +25,7 @@
#include <linux/async.h>
#include <linux/posix_acl.h>
#include <linux/ima.h>
+#include <linux/cred.h>
/*
* This is needed for the following functions:
@@ -1733,3 +1734,19 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
inode->i_mode = mode;
}
EXPORT_SYMBOL(inode_init_owner);
+
+/*
+ * return true if current either has CAP_FOWNER to the
+ * file, or owns the file.
+ */
+bool is_owner_or_cap(const struct inode *inode)
+{
+ struct user_namespace *ns = inode_userns(inode);
+
+ if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
+ return true;
+ if (ns_capable(ns, CAP_FOWNER))
+ return true;
+ return false;
+}
+EXPORT_SYMBOL(is_owner_or_cap);