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authorJo-Philipp Wich <jo@mein.io>2016-06-11 00:53:16 +0200
committerJo-Philipp Wich <jo@mein.io>2016-06-11 00:53:19 +0200
commit442db0d6d8614c354c1c1ce705dd57d020680bac (patch)
tree4b4ada48c6c5bc2015b2a600a1816231d48631b1
parentdd182011e1acabc94169b85f3bc63efbab72ddd4 (diff)
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kernel: deny swconfig set requests for unprivileged users
The swconfig kernel infrastructure fails to do any permissions checks when changing settings. As such an ordinary user account on a device with a switch can change switch settings without any special permissions. Routers generally have few non-admin users so this isn't a big hole, but it is a security hole. Likely the greatest danger is for multifunction devices which have a lot of extra daemons, compromising a low-security daemon would allow one to modify switch settings and cause the router/switch to appear to lock-up (or cause other sorts of troublesome nyetwork behavior). Implement a check for CAP_NET_ADMIN in swconfig_set_attr() and deny any requests originating from user contexts lacking this capability. Reported-by: Elliott Mitchell <ehem+openwrt@m5p.com> Signed-off-by: Jo-Philipp Wich <jo@mein.io>
-rw-r--r--target/linux/generic/files/drivers/net/phy/swconfig.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/target/linux/generic/files/drivers/net/phy/swconfig.c b/target/linux/generic/files/drivers/net/phy/swconfig.c
index b556510aef..699abd33dd 100644
--- a/target/linux/generic/files/drivers/net/phy/swconfig.c
+++ b/target/linux/generic/files/drivers/net/phy/swconfig.c
@@ -635,6 +635,9 @@ swconfig_set_attr(struct sk_buff *skb, struct genl_info *info)
struct switch_val val;
int err = -EINVAL;
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+
dev = swconfig_get_dev(info);
if (!dev)
return -EINVAL;