Commit a4e3b8d7 authored May 22, 2014 by Mimi Zohar

KEYS: special dot prefixed keyring name bug fix



Dot prefixed keyring names are supposed to be reserved for the
kernel, but add_key() calls key_get_type_from_user(), which
incorrectly verifies the 'type' field, not the 'description' field.
This patch verifies the 'description' field isn't dot prefixed,
when creating a new keyring, and removes the dot prefix test in
key_get_type_from_user().

Changelog v6:
- whitespace and other cleanup

Changelog v5:
- Only prevent userspace from creating a dot prefixed keyring, not
  regular keys  - Dmitry

Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>

parent 32c2e675

security/keys/keyctl.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -37,8 +37,6 @@ static int key_get_type_from_user(char *type,
	return ret;		return ret;
	if (ret == 0 \|\| ret >= len)		if (ret == 0 \|\| ret >= len)
	return -EINVAL;		return -EINVAL;
	if (type[0] == '.')
	return -EPERM;
	type[len - 1] = '\0';		type[len - 1] = '\0';
	return 0;		return 0;
	}		}
	@@ -86,6 +84,10 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
	if (!*description) {		if (!*description) {
	kfree(description);		kfree(description);
	description = NULL;		description = NULL;
			} else if ((description[0] == '.') &&
			(strncmp(type, "keyring", 7) == 0)) {
			ret = -EPERM;
			goto error2;
	}		}
	}		}