diff mbox series

[RFC,v4,2/2] security/inode.c: Add capabilities file.

Message ID 20220725124123.12975-3-flaniel@linux.microsoft.com (mailing list archive)
State Rejected
Delegated to: Paul Moore
Headers show
Series Add capabilities file to securityfs | expand

Commit Message

Francis Laniel July 25, 2022, 12:41 p.m. UTC 
This new read-only file prints the capabilities values with their names:
cat /sys/kernel/security/capabilities
0       CAP_CHOWN
1       CAP_DAC_OVERRIDE
...
40      CAP_CHECKPOINT_RESTORE

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Francis Laniel <flaniel@linux.microsoft.com>
---
 security/inode.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/security/inode.c b/security/inode.c
index 6c326939750d..6da87ae5a8d6 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -21,6 +21,7 @@ 
 #include <linux/security.h>
 #include <linux/lsm_hooks.h>
 #include <linux/magic.h>
+#include <linux/capability.h>
 
 static struct vfsmount *mount;
 static int mount_count;
@@ -328,6 +329,19 @@  static const struct file_operations lsm_ops = {
 };
 #endif
 
+static struct dentry *capabilities_dentry;
+static ssize_t capabilities_read(struct file *unused, char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	return simple_read_from_buffer(buf, count, ppos, cap_string,
+				       strlen(cap_string));
+}
+
+static const struct file_operations capabilities_ops = {
+	.read = capabilities_read,
+	.llseek = generic_file_llseek,
+};
+
 static int __init securityfs_init(void)
 {
 	int retval;
@@ -345,6 +359,8 @@  static int __init securityfs_init(void)
 	lsm_dentry = securityfs_create_file("lsm", 0444, NULL, NULL,
 						&lsm_ops);
 #endif
+	capabilities_dentry = securityfs_create_file("capabilities", 0444, NULL,
+						     NULL, &capabilities_ops);
 	return 0;
 }
 core_initcall(securityfs_init);