[prev in list] [next in list] [prev in thread] [next in thread]
List: linux-keyrings
Subject: [PATCH 2/7] FS-Cache: fix dereference of NULL user_key_payload
From: Eric Biggers <ebiggers3 () gmail ! com>
Date: 2017-09-28 21:25:57
Message-ID: 20170928212602.41744-3-ebiggers3 () gmail ! com
[Download RAW message or body]
From: Eric Biggers <ebiggers@google.com>
When the file /proc/fs/fscache/objects (available with
CONFIG_FSCACHE_OBJECT_LIST=y) is opened, we request a user key with
description "fscache:objlist", then access its payload. However, a
revoked key has a NULL payload, and we failed to check for this.
request_key() *does* skip revoked keys, but there is still a window
where the key can be revoked before we access its payload.
Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.
Fixes: 4fbf4291aa15 ("FS-Cache: Allow the current state of all objects to be dumped")
Cc: <stable@vger.kernel.org> [v2.6.32+]
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
fs/fscache/object-list.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index b5ab06fabc60..0438d4cd91ef 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -331,6 +331,13 @@ static void fscache_objlist_config(struct fscache_objlist_data *data)
rcu_read_lock();
confkey = user_key_payload_rcu(key);
+ if (!confkey) {
+ /* key was revoked */
+ rcu_read_unlock();
+ key_put(key);
+ goto no_config;
+ }
+
buf = confkey->data;
for (len = confkey->datalen - 1; len >= 0; len--) {
--
2.14.2.822.g60be5d43e6-goog
--
To unsubscribe from this list: send the line "unsubscribe keyrings" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic