| Message ID | 20190415205723.GA31452@embeddedor |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: atm: Fix potential Spectre v1 vulnerabilities | expand |
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com> Date: Mon, 15 Apr 2019 15:57:23 -0500 > 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> Applied and queued up for -stable.
On 4/16/19 11:02 PM, David Miller wrote: > From: "Gustavo A. R. Silva" <gustavo@embeddedor.com> > Date: Mon, 15 Apr 2019 15:57:23 -0500 > >> 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> > > Applied and queued up for -stable. > Thank you, Dave. -- Gustavo
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;
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> --- net/atm/lec.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)