From: Gustavo A. R. Silva Date: Fri, 21 Dec 2018 21:41:17 +0000 (-0600) Subject: phonet: af_phonet: Fix Spectre v1 vulnerability X-Git-Tag: Ubuntu-5.10.0-12.13~6343^2^2~9 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=d686026b1e6ed4ea27d630d8f54f9a694db088b2;p=mirror_ubuntu-hirsute-kernel.git 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 Signed-off-by: David S. Miller --- 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 #include +#include + /* 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]);