proto 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/nfc/af_nfc.c:42 nfc_sock_create() warn: potential spectre issue 'proto_tab' [w] (local cap) Fix this by sanitizing proto 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@xxxxxxxxxxxxxx> --- net/nfc/af_nfc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/nfc/af_nfc.c b/net/nfc/af_nfc.c index d3e594eb36d0..256f3c57059e 100644 --- a/net/nfc/af_nfc.c +++ b/net/nfc/af_nfc.c @@ -21,6 +21,7 @@ #include <linux/nfc.h> #include <linux/module.h> +#include <linux/nospec.h> #include "nfc.h" @@ -37,6 +38,7 @@ static int nfc_sock_create(struct net *net, struct socket *sock, int proto, if (proto < 0 || proto >= NFC_SOCKPROTO_MAX) return -EINVAL; + proto = array_index_nospec(proto, NFC_SOCKPROTO_MAX); read_lock(&proto_tab_lock); if (proto_tab[proto] && try_module_get(proto_tab[proto]->owner)) { -- 2.20.1
