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-rw-r--r--security/keys/keyctl.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 1698bf90ee8..56e963b700b 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -20,6 +20,7 @@
#include <linux/string.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
+#include <linux/security.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -1080,6 +1081,66 @@ error:
} /* end keyctl_assume_authority() */
+/*
+ * get the security label of a key
+ * - the key must grant us view permission
+ * - if there's a buffer, we place up to buflen bytes of data into it
+ * - unless there's an error, we return the amount of information available,
+ * irrespective of how much we may have copied (including the terminal NUL)
+ * - implements keyctl(KEYCTL_GET_SECURITY)
+ */
+long keyctl_get_security(key_serial_t keyid,
+ char __user *buffer,
+ size_t buflen)
+{
+ struct key *key, *instkey;
+ key_ref_t key_ref;
+ char *context;
+ long ret;
+
+ key_ref = lookup_user_key(NULL, keyid, 0, 1, KEY_VIEW);
+ if (IS_ERR(key_ref)) {
+ if (PTR_ERR(key_ref) != -EACCES)
+ return PTR_ERR(key_ref);
+
+ /* viewing a key under construction is also permitted if we
+ * have the authorisation token handy */
+ instkey = key_get_instantiation_authkey(keyid);
+ if (IS_ERR(instkey))
+ return PTR_ERR(key_ref);
+ key_put(instkey);
+
+ key_ref = lookup_user_key(NULL, keyid, 0, 1, 0);
+ if (IS_ERR(key_ref))
+ return PTR_ERR(key_ref);
+ }
+
+ key = key_ref_to_ptr(key_ref);
+ ret = security_key_getsecurity(key, &context);
+ if (ret == 0) {
+ /* if no information was returned, give userspace an empty
+ * string */
+ ret = 1;
+ if (buffer && buflen > 0 &&
+ copy_to_user(buffer, "", 1) != 0)
+ ret = -EFAULT;
+ } else if (ret > 0) {
+ /* return as much data as there's room for */
+ if (buffer && buflen > 0) {
+ if (buflen > ret)
+ buflen = ret;
+
+ if (copy_to_user(buffer, context, buflen) != 0)
+ ret = -EFAULT;
+ }
+
+ kfree(context);
+ }
+
+ key_ref_put(key_ref);
+ return ret;
+}
+
/*****************************************************************************/
/*
* the key control system call
@@ -1160,6 +1221,11 @@ asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
case KEYCTL_ASSUME_AUTHORITY:
return keyctl_assume_authority((key_serial_t) arg2);
+ case KEYCTL_GET_SECURITY:
+ return keyctl_get_security((key_serial_t) arg2,
+ (char *) arg3,
+ (size_t) arg4);
+
default:
return -EOPNOTSUPP;
}