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authorJason A. Donenfeld <Jason@zx2c4.com>2017-09-27 14:34:19 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2017-09-28 00:40:26 +0200
commit865ea53745c409b8a9491a519e116a613e0c716c (patch)
tree426c7ba4ea3d3bfd0a3d2d8be5ffd301b8f6cba0
parentMerge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi (diff)
downloadlinux-dev-865ea53745c409b8a9491a519e116a613e0c716c.tar.xz
linux-dev-865ea53745c409b8a9491a519e116a613e0c716c.zip
netlink: do not proceed if dump's start() errsjd/broken-netlink-dump
Drivers that use the start method for netlink dumping rely on dumpit not being called if start fails. For example, ila_xlat.c allocates memory and assigns it to cb->args[0] in its start() function. It might fail to do that and return -ENOMEM instead. However, even when returning an error, dumpit will be called, which, in the example above, quickly dereferences the memory in cb->args[0], which will OOPS the kernel. This is but one example of how this goes wrong. Since start() has always been a function with an int return type, it therefore makes sense to use it properly, rather than ignoring it. This patch thus returns early and does not call dumpit() when start() fails. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Johannes Berg <johannes@sipsolutions.net>
-rw-r--r--net/netlink/af_netlink.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 327807731b44..94c11cf0459d 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2270,10 +2270,13 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
mutex_unlock(nlk->cb_mutex);
+ ret = 0;
if (cb->start)
- cb->start(cb);
+ ret = cb->start(cb);
+
+ if (!ret)
+ ret = netlink_dump(sk);
- ret = netlink_dump(sk);
sock_put(sk);
if (ret)