[PATCH, RFC 31/62] keys/mktme: Require CAP_SYS_RESOURCE capability for MKTME keys

[Kirill A. Shutemov]

From: Alison Schofield <alison.schofield@xxxxxxxxx>

The MKTME key type uses capabilities to restrict the allocation
of keys to privileged users. CAP_SYS_RESOURCE is required, but
the broader capability of CAP_SYS_ADMIN is accepted.

Signed-off-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 security/keys/mktme_keys.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/security/keys/mktme_keys.c b/security/keys/mktme_keys.c
index 496b5c1b7461..4b2d3dc1843a 100644
--- a/security/keys/mktme_keys.c
+++ b/security/keys/mktme_keys.c
@@ -2,6 +2,7 @@
 
 /* Documentation/x86/mktme_keys.rst */
 
+#include <linux/cred.h>
 #include <linux/cpu.h>
 #include <linux/init.h>
 #include <linux/key.h>
@@ -393,6 +394,9 @@ int mktme_preparse_payload(struct key_preparsed_payload *prep)
 	char *options;
 	int ret;
 
+	if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
 	if (datalen <= 0 || datalen > 1024 || !prep->data)
 		return -EINVAL;
 
-- 
2.20.1