This is a note to let you know that I've just added the patch titled
Add file_ns_capable() helper function for open-time capability checking
to the 3.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
add-file_ns_capable-helper-function-for-open-time-capability-checking.patch
and it can be found in the queue-3.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 935d8aabd4331f47a89c3e1daa5779d23cf244ee Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date: Sun, 14 Apr 2013 10:06:31 -0700
Subject: Add file_ns_capable() helper function for open-time capability checking
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
commit 935d8aabd4331f47a89c3e1daa5779d23cf244ee upstream.
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@xxxxxxxxxxxxxxxxxxxx>
Cc: Shea Levy <shea@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/capability.h | 2 ++
kernel/capability.c | 24 ++++++++++++++++++++++++
2 files changed, 26 insertions(+)
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -35,6 +35,7 @@ struct cpu_vfs_cap_data {
#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
+struct file;
struct inode;
struct dentry;
struct user_namespace;
@@ -211,6 +212,7 @@ extern bool capable(int cap);
extern bool ns_capable(struct user_namespace *ns, int cap);
extern bool nsown_capable(int cap);
extern bool inode_capable(const struct inode *inode, int cap);
+extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
/* audit system wants to get cap info from files as well */
extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -393,6 +393,30 @@ bool ns_capable(struct user_namespace *n
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
*
Patches currently in stable-queue which might be from torvalds@xxxxxxxxxxxxxxxxxxxx are
queue-3.8/add-file_ns_capable-helper-function-for-open-time-capability-checking.patch
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