From: Gustavo A. R. Silva Date: Mon, 15 Apr 2019 20:57:23 +0000 (-0500) Subject: net: atm: Fix potential Spectre v1 vulnerabilities X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9fac50c39253b6bef74c2cfc2244a93c4d5a0896;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git net: atm: Fix potential Spectre v1 vulnerabilities [ Upstream commit 899537b73557aafbdd11050b501cf54b4f5c45af ] 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/atm/lec.c b/net/atm/lec.c index 9f2365694ad4..85ce89c8a35c 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;