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authorLinus Torvalds <torvalds@linux-foundation.org>2013-04-14 10:06:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-14 10:06:31 -0700
commit935d8aabd4331f47a89c3e1daa5779d23cf244ee (patch)
tree8fff6fba14f11a55cea7a9fd3adc2e8d418b4ee1 /kernel/capability.c
parent5b55d708335a9e3e4f61f2dadf7511502205ccd1 (diff)
downloadlinux-sh-935d8aabd4331f47a89c3e1daa5779d23cf244ee.tar.gz
Add file_ns_capable() helper function for open-time capability checking
Nothing is using it yet, but this will allow us to delay the open-time checks to use time, without breaking the normal UNIX permission semantics where permissions are determined by the opener (and the file descriptor can then be passed to a different process, or the process can drop capabilities). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/capability.c')
-rw-r--r--kernel/capability.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/capability.c b/kernel/capability.c
index 493d97259484..f6c2ce5701e1 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -393,6 +393,30 @@ bool ns_capable(struct user_namespace *ns, int cap)
EXPORT_SYMBOL(ns_capable);
/**
+ * file_ns_capable - Determine if the file's opener had a capability in effect
+ * @file: The file we want to check
+ * @ns: The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if task that opened the file had a capability in effect
+ * when the file was opened.
+ *
+ * This does not set PF_SUPERPRIV because the caller may not
+ * actually be privileged.
+ */
+bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap)
+{
+ if (WARN_ON_ONCE(!cap_valid(cap)))
+ return false;
+
+ if (security_capable(file->f_cred, ns, cap) == 0)
+ return true;
+
+ return false;
+}
+EXPORT_SYMBOL(file_ns_capable);
+
+/**
* capable - Determine if the current task has a superior capability in effect
* @cap: The capability to be tested for
*