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From 164a98ea6b24fea3433516dcc0df496929674cdd Mon Sep 17 00:00:00 2001
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From: Jan Synacek <jsynacek@redhat.com>
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Date: Tue, 7 Jun 2016 12:43:38 +0200
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Subject: [PATCH] sd-netlink: fix deep recursion in message destruction
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On larger systems we might very well see messages with thousands of parts.
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When we free them, we must avoid recursing into each part, otherwise we
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very likely get stack overflows.
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Fix sd_netlink_message_unref() to use an iterative approach rather than
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recursion (also avoid tail-recursion in case it is not optimized by the
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compiler).
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(cherry picked from commit 82e4eda664d40ef60829e27d84b1610c2f4070cd)
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Resolves: #1330593
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---
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src/libsystemd/sd-rtnl/rtnl-message.c | 10 ++++++----
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1 file changed, 6 insertions(+), 4 deletions(-)
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diff --git a/src/libsystemd/sd-rtnl/rtnl-message.c b/src/libsystemd/sd-rtnl/rtnl-message.c
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index 276591f31..9276bbdeb 100644
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--- a/src/libsystemd/sd-rtnl/rtnl-message.c
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+++ b/src/libsystemd/sd-rtnl/rtnl-message.c
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@@ -584,7 +584,9 @@ sd_rtnl_message *sd_rtnl_message_ref(sd_rtnl_message *m) {
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}
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sd_rtnl_message *sd_rtnl_message_unref(sd_rtnl_message *m) {
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- if (m && REFCNT_DEC(m->n_ref) == 0) {
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+ sd_rtnl_message *t;
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+
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+ while (m && REFCNT_DEC(m->n_ref) == 0) {
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unsigned i;
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free(m->hdr);
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@@ -592,9 +594,9 @@ sd_rtnl_message *sd_rtnl_message_unref(sd_rtnl_message *m) {
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for (i = 0; i <= m->n_containers; i++)
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free(m->rta_offset_tb[i]);
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- sd_rtnl_message_unref(m->next);
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-
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- free(m);
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+ t = m;
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+ m = m->next;
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+ free(t);
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}
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return NULL;
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