3.2.88-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
The "dead" key type has no match operation, and a search for keys of
this type can cause a null dereference in keyring_search_aux().
keyring_search() has a check for this, but request_keyring_and_link()
does not. Move the check into keyring_search_aux(), covering both of
them.
This was fixed upstream by commit c06cfb08b88d ("KEYS: Remove
key_type::match in favour of overriding default by match_preparse"),
part of a series of large changes that are not suitable for
backporting.
CVE-2017-2647 / CVE-2017-6951
Reported-by: Igor Redko <redkoi@xxxxxxxxxxxxx>
Reported-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
References: https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2647
Reported-by: idl3r <idler1984@xxxxxxxxx>
References: https://www.spinics.net/lists/keyrings/msg01845.html
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
---
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -336,6 +336,9 @@ key_ref_t keyring_search_aux(key_ref_t k
if (keyring->type != &key_type_keyring)
goto error;
+ if (!match)
+ return ERR_PTR(-ENOKEY);
+
rcu_read_lock();
now = current_kernel_time();
@@ -484,9 +487,6 @@ key_ref_t keyring_search(key_ref_t keyri
struct key_type *type,
const char *description)
{
- if (!type->match)
- return ERR_PTR(-ENOKEY);
-
return keyring_search_aux(keyring, current->cred,
type, description, type->match, false);
}