diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-14 10:06:31 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-04-26 12:18:20 -0700 |
| commit | 97129f70b9a32ddf8929daacd2abee36a7f0ddad (patch) | |
| tree | 0f6bcfc24b2b7e90eff69d4f4550e7c43e2073b3 | |
| parent | 8299a17a0544a45529a954cf27f9bf40e8890ac6 (diff) | |
Add file_ns_capable() helper function for open-time capability checking
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@linux-foundation.org>
Cc: Shea Levy <shea@shealevy.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/capability.h | 2 | ||||
| -rw-r--r-- | kernel/capability.c | 24 |
2 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h index 98503b79236..d9a4f7f40f3 100644 --- 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); diff --git a/kernel/capability.c b/kernel/capability.c index 493d9725948..f6c2ce5701e 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 * |