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authorJohannes Berg <johannes.berg@intel.com>2019-03-15 16:33:18 +0200
committerHauke Mehrtens <hauke@hauke-m.de>2019-03-28 00:08:12 +0100
commit86e670f41afd3199699339393740a7c401fb26f1 (patch)
tree1dadb51096af92e2e1c8c9931c85502804caf47f
parent9a973d908cea50d0625f7c19d80dfca9435a49d7 (diff)
backports: genetlink: avoid NULL dereference
If we fail to allocate extack, we fall back to the code path that tries to send an error *with* extack, but that will access our extack pointer. It also doesn't make sense, so just return an error back to netlink immediately and let it handle sending the error message to userspace. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
-rw-r--r--backport/compat/backport-genetlink.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/backport/compat/backport-genetlink.c b/backport/compat/backport-genetlink.c
index 71bf45ad..885f1756 100644
--- a/backport/compat/backport-genetlink.c
+++ b/backport/compat/backport-genetlink.c
@@ -157,12 +157,10 @@ static int backport_pre_doit(__genl_const struct genl_ops *ops,
#if LINUX_VERSION_IS_LESS(4,12,0)
struct netlink_ext_ack *extack = kzalloc(sizeof(*extack), GFP_KERNEL);
- __bp_genl_info_userhdr_set(info, extack);
+ if (!extack)
+ return -ENOMEM;
- if (!extack) {
- err = -ENOMEM;
- goto err;
- }
+ __bp_genl_info_userhdr_set(info, extack);
extack->__bp_doit = ops->doit;
#else
@@ -175,7 +173,6 @@ static int backport_pre_doit(__genl_const struct genl_ops *ops,
err = family->pre_doit(ops, skb, info);
#if LINUX_VERSION_IS_LESS(4,12,0)
-err:
if (err) {
/* signal to do nothing */
extack->__bp_doit = NULL;