Commit 8f0eb24f authored Jan 20, 2023 by Eric Dumazet Committed by Greg Kroah-Hartman Feb 06, 2023

ipv4: prevent potential spectre v1 gadget in fib_metrics_match()



[ Upstream commit 5e9398a26a92fc402d82ce1f97cc67d832527da0 ]

if (!type)
        continue;
    if (type > RTAX_MAX)
        return false;
    ...
    fi_val = fi->fib_metrics->metrics[type - 1];

@type being used as an array index, we need to prevent
cpu speculation or risk leaking kernel memory content.

Fixes: 5f9ae3d9 ("ipv4: do metrics match when looking up and deleting a route")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230120133140.3624204-1-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 746db9ec

net/ipv4/fib_semantics.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@
		#include <linux/slab.h>
		#include <linux/netlink.h>
		#include <linux/hash.h>
		#include <linux/nospec.h>

		#include <net/arp.h>
		#include <net/ip.h>
		@@ -1009,6 +1010,7 @@ bool fib_metrics_match(struct fib_config cfg, struct fib_info fi)
		if (type > RTAX_MAX)
		return false;

		type = array_index_nospec(type, RTAX_MAX + 1);
		if (type == RTAX_CC_ALGO) {
		char tmp[TCP_CA_NAME_MAX];
		bool ecn_ca = false;