Messages in this thread Patch in this message | | | Date | Mon, 06 May 2013 23:58:43 -0400 | From | Steven Rostedt <> | Subject | [091/126] Add file_ns_capable() helper function for open-time capability checking |
| |
3.6.11.3 stable review patch. If anyone has any objections, please let me know.
------------------
From: Linus Torvalds <torvalds@linux-foundation.org>
[ Upstream commit 935d8aabd4331f47a89c3e1daa5779d23cf244ee ]
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> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- include/linux/capability.h | 2 ++ kernel/capability.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/include/linux/capability.h b/include/linux/capability.h index d10b7ed..19e11d4 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -377,6 +377,7 @@ struct cpu_vfs_cap_data { #ifdef __KERNEL__ +struct file; struct inode; struct dentry; struct user_namespace; @@ -553,6 +554,7 @@ 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); diff --git a/kernel/capability.c b/kernel/capability.c index 493d972..f6c2ce5 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 * -- 1.7.10.4
| |