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Message-ID: <20230120133140.3624204-1-edumazet@google.com>
Date: Fri, 20 Jan 2023 13:31:40 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net] ipv4: prevent potential spectre v1 gadget in fib_metrics_match()
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: 5f9ae3d9e7e4 ("ipv4: do metrics match when looking up and deleting a route")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/fib_semantics.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index ce9ff3c62e84055393ca1ff98f1d2ae391978638..3bb890a40ed73626acba8c22044d1c5f99c872e8 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -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/inet_dscp.h>
@@ -1022,6 +1023,7 @@ 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;
--
2.39.1.405.gd4c25cc71f-goog
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