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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-21 15:41:17 -0600
committerDavid S. Miller <davem@davemloft.net>2018-12-22 15:08:15 -0800
commitd686026b1e6ed4ea27d630d8f54f9a694db088b2 (patch)
treed7bd2f44af64de4131d4dcfb161f6d6c9e18bcc1 /net
parent50d5258634aee2e62832aa086d2fb0de00e72b91 (diff)
phonet: af_phonet: Fix Spectre v1 vulnerability
protocol is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: net/phonet/af_phonet.c:48 phonet_proto_get() warn: potential spectre issue 'proto_tab' [w] (local cap) Fix this by sanitizing protocol before using it to index proto_tab. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/phonet/af_phonet.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 3b0ef691f5b1..d4b2abd78858 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -34,6 +34,8 @@
#include <net/phonet/phonet.h>
#include <net/phonet/pn_dev.h>
+#include <linux/nospec.h>
+
/* Transport protocol registration */
static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
@@ -43,6 +45,7 @@ static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
if (protocol >= PHONET_NPROTO)
return NULL;
+ protocol = array_index_nospec(protocol, PHONET_NPROTO);
rcu_read_lock();
pp = rcu_dereference(proto_tab[protocol]);

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