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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-04-15 15:57:23 -0500
committerDavid S. Miller <davem@davemloft.net>2019-04-16 21:01:45 -0700
commit899537b73557aafbdd11050b501cf54b4f5c45af (patch)
treefb231860e44e0e39982d5bf475c569b79bce1003
parentad910c7c01269f229a97c335f2dc669fff750f65 (diff)
net: atm: Fix potential Spectre v1 vulnerabilities
arg is 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/atm/lec.c:715 lec_mcast_attach() warn: potential spectre issue 'dev_lec' [r] (local cap) Fix this by sanitizing arg before using it to index dev_lec. 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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/ Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/atm/lec.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/atm/lec.c b/net/atm/lec.c
index d7f5cf5b7594..ad4f829193f0 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -710,7 +710,10 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg)
static int lec_mcast_attach(struct atm_vcc *vcc, int arg)
{
- if (arg < 0 || arg >= MAX_LEC_ITF || !dev_lec[arg])
+ if (arg < 0 || arg >= MAX_LEC_ITF)
+ return -EINVAL;
+ arg = array_index_nospec(arg, MAX_LEC_ITF);
+ if (!dev_lec[arg])
return -EINVAL;
vcc->proto_data = dev_lec[arg];
return lec_mcast_make(netdev_priv(dev_lec[arg]), vcc);
@@ -728,6 +731,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg)
i = arg;
if (arg >= MAX_LEC_ITF)
return -EINVAL;
+ i = array_index_nospec(arg, MAX_LEC_ITF);
if (!dev_lec[i]) {
int size;