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-rw-r--r--Documentation/keys.txt21
-rw-r--r--include/linux/keyctl.h1
-rw-r--r--include/linux/security.h20
-rw-r--r--security/dummy.c8
-rw-r--r--security/keys/compat.c3
-rw-r--r--security/keys/internal.h3
-rw-r--r--security/keys/keyctl.c66
-rw-r--r--security/security.c5
-rw-r--r--security/selinux/hooks.c15
9 files changed, 140 insertions, 2 deletions
diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index b82d38de8b8..be424b02437 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -711,6 +711,27 @@ The keyctl syscall functions are:
The assumed authoritative key is inherited across fork and exec.
+ (*) Get the LSM security context attached to a key.
+
+ long keyctl(KEYCTL_GET_SECURITY, key_serial_t key, char *buffer,
+ size_t buflen)
+
+ This function returns a string that represents the LSM security context
+ attached to a key in the buffer provided.
+
+ Unless there's an error, it always returns the amount of data it could
+ produce, even if that's too big for the buffer, but it won't copy more
+ than requested to userspace. If the buffer pointer is NULL then no copy
+ will take place.
+
+ A NUL character is included at the end of the string if the buffer is
+ sufficiently big. This is included in the returned count. If no LSM is
+ in force then an empty string will be returned.
+
+ A process must have view permission on the key for this function to be
+ successful.
+
+
===============
KERNEL SERVICES
===============
diff --git a/include/linux/keyctl.h b/include/linux/keyctl.h
index 3365945640c..656ee6b77a4 100644
--- a/include/linux/keyctl.h
+++ b/include/linux/keyctl.h
@@ -49,5 +49,6 @@
#define KEYCTL_SET_REQKEY_KEYRING 14 /* set default request-key keyring */
#define KEYCTL_SET_TIMEOUT 15 /* set key timeout */
#define KEYCTL_ASSUME_AUTHORITY 16 /* assume request_key() authorisation */
+#define KEYCTL_GET_SECURITY 17 /* get key security label */
#endif /* _LINUX_KEYCTL_H */
diff --git a/include/linux/security.h b/include/linux/security.h
index 3ebcdd00b17..adb09d893ae 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1009,6 +1009,17 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* @perm describes the combination of permissions required of this key.
* Return 1 if permission granted, 0 if permission denied and -ve it the
* normal permissions model should be effected.
+ * @key_getsecurity:
+ * Get a textual representation of the security context attached to a key
+ * for the purposes of honouring KEYCTL_GETSECURITY. This function
+ * allocates the storage for the NUL-terminated string and the caller
+ * should free it.
+ * @key points to the key to be queried.
+ * @_buffer points to a pointer that should be set to point to the
+ * resulting string (if no label or an error occurs).
+ * Return the length of the string (including terminating NUL) or -ve if
+ * an error.
+ * May also return 0 (and a NULL buffer pointer) if there is no label.
*
* Security hooks affecting all System V IPC operations.
*
@@ -1538,7 +1549,7 @@ struct security_operations {
int (*key_permission) (key_ref_t key_ref,
struct task_struct *context,
key_perm_t perm);
-
+ int (*key_getsecurity)(struct key *key, char **_buffer);
#endif /* CONFIG_KEYS */
#ifdef CONFIG_AUDIT
@@ -2732,6 +2743,7 @@ int security_key_alloc(struct key *key, struct task_struct *tsk, unsigned long f
void security_key_free(struct key *key);
int security_key_permission(key_ref_t key_ref,
struct task_struct *context, key_perm_t perm);
+int security_key_getsecurity(struct key *key, char **_buffer);
#else
@@ -2753,6 +2765,12 @@ static inline int security_key_permission(key_ref_t key_ref,
return 0;
}
+static inline int security_key_getsecurity(struct key *key, char **_buffer)
+{
+ *_buffer = NULL;
+ return 0;
+}
+
#endif
#endif /* CONFIG_KEYS */
diff --git a/security/dummy.c b/security/dummy.c
index 26ee06ef0e9..48cf30226e1 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -994,6 +994,13 @@ static inline int dummy_key_permission(key_ref_t key_ref,
{
return 0;
}
+
+static int dummy_key_getsecurity(struct key *key, char **_buffer)
+{
+ *_buffer = NULL;
+ return 0;
+}
+
#endif /* CONFIG_KEYS */
#ifdef CONFIG_AUDIT
@@ -1210,6 +1217,7 @@ void security_fixup_ops (struct security_operations *ops)
set_to_dummy_if_null(ops, key_alloc);
set_to_dummy_if_null(ops, key_free);
set_to_dummy_if_null(ops, key_permission);
+ set_to_dummy_if_null(ops, key_getsecurity);
#endif /* CONFIG_KEYS */
#ifdef CONFIG_AUDIT
set_to_dummy_if_null(ops, audit_rule_init);
diff --git a/security/keys/compat.c b/security/keys/compat.c
index e10ec995f27..c766c68a63b 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -79,6 +79,9 @@ asmlinkage long compat_sys_keyctl(u32 option,
case KEYCTL_ASSUME_AUTHORITY:
return keyctl_assume_authority(arg2);
+ case KEYCTL_GET_SECURITY:
+ return keyctl_get_security(arg2, compat_ptr(arg3), arg4);
+
default:
return -EOPNOTSUPP;
}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 3cc04c2afe1..6361d3736db 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -155,7 +155,8 @@ extern long keyctl_negate_key(key_serial_t, unsigned, key_serial_t);
extern long keyctl_set_reqkey_keyring(int);
extern long keyctl_set_timeout(key_serial_t, unsigned);
extern long keyctl_assume_authority(key_serial_t);
-
+extern long keyctl_get_security(key_serial_t keyid, char __user *buffer,
+ size_t buflen);
/*
* debugging key validation
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;
}
diff --git a/security/security.c b/security/security.c
index a809035441a..8e64a29dc55 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1156,6 +1156,11 @@ int security_key_permission(key_ref_t key_ref,
return security_ops->key_permission(key_ref, context, perm);
}
+int security_key_getsecurity(struct key *key, char **_buffer)
+{
+ return security_ops->key_getsecurity(key, _buffer);
+}
+
#endif /* CONFIG_KEYS */
#ifdef CONFIG_AUDIT
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 047365ac9fa..838d1e5e63a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5300,6 +5300,20 @@ static int selinux_key_permission(key_ref_t key_ref,
SECCLASS_KEY, perm, NULL);
}
+static int selinux_key_getsecurity(struct key *key, char **_buffer)
+{
+ struct key_security_struct *ksec = key->security;
+ char *context = NULL;
+ unsigned len;
+ int rc;
+
+ rc = security_sid_to_context(ksec->sid, &context, &len);
+ if (!rc)
+ rc = len;
+ *_buffer = context;
+ return rc;
+}
+
#endif
static struct security_operations selinux_ops = {
@@ -5488,6 +5502,7 @@ static struct security_operations selinux_ops = {
.key_alloc = selinux_key_alloc,
.key_free = selinux_key_free,
.key_permission = selinux_key_permission,
+ .key_getsecurity = selinux_key_getsecurity,
#endif
#ifdef CONFIG_AUDIT