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authorJakub Kicinski <kuba@kernel.org>2022-08-16 09:19:39 -0700
committerJakub Kicinski <kuba@kernel.org>2022-08-18 10:20:48 -0700
commit249801360db3dec4f73768c502192020bfddeacc (patch)
tree12f45371df138671e0ef5f3f6b0fdb3692b4dbe2 /net/netlink
parent5c23d6b717e4e956376f3852b90f58e262946b50 (diff)
net: genl: fix error path memory leak in policy dumping
If construction of the array of policies fails when recording non-first policy we need to unwind. netlink_policy_dump_add_policy() itself also needs fixing as it currently gives up on error without recording the allocated pointer in the pstate pointer. Reported-by: syzbot+dc54d9ba8153b216cae0@syzkaller.appspotmail.com Fixes: 50a896cf2d6f ("genetlink: properly support per-op policy dumping") Link: https://lore.kernel.org/r/20220816161939.577583-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/genetlink.c6
-rw-r--r--net/netlink/policy.c14
2 files changed, 17 insertions, 3 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 1afca2a6c2ac..57010927e20a 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1174,13 +1174,17 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
op.policy,
op.maxattr);
if (err)
- return err;
+ goto err_free_state;
}
}
if (!ctx->state)
return -ENODATA;
return 0;
+
+err_free_state:
+ netlink_policy_dump_free(ctx->state);
+ return err;
}
static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
diff --git a/net/netlink/policy.c b/net/netlink/policy.c
index 8d7c900e27f4..87e3de0fde89 100644
--- a/net/netlink/policy.c
+++ b/net/netlink/policy.c
@@ -144,7 +144,7 @@ int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate,
err = add_policy(&state, policy, maxtype);
if (err)
- return err;
+ goto err_try_undo;
for (policy_idx = 0;
policy_idx < state->n_alloc && state->policies[policy_idx].policy;
@@ -164,7 +164,7 @@ int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate,
policy[type].nested_policy,
policy[type].len);
if (err)
- return err;
+ goto err_try_undo;
break;
default:
break;
@@ -174,6 +174,16 @@ int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate,
*pstate = state;
return 0;
+
+err_try_undo:
+ /* Try to preserve reasonable unwind semantics - if we're starting from
+ * scratch clean up fully, otherwise record what we got and caller will.
+ */
+ if (!*pstate)
+ netlink_policy_dump_free(state);
+ else
+ *pstate = state;
+ return err;
}
static bool