Description
In the Linux kernel, the following vulnerability has been resolved: can: sun4i_can: populate ndo_change_mtu() to prevent buffer overflow Sending an PF_PACKET allows to bypass the CAN framework logic and to directly reach the xmit() function of a CAN driver. The only check which is performed by the PF_PACKET framework is to make sure that skb->len fits the interface's MTU. Unfortunately, because the sun4i_can driver does not populate its net_device_ops->ndo_change_mtu(), it is possible for an attacker to configure an invalid MTU by doing, for example: $ ip link set can0 mtu 9999 After doing so, the attacker could open a PF_PACKET socket using the ETH_P_CANXL protocol: socket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL)) to inject a malicious CAN XL frames. For example: struct canxl_frame frame = { .flags = 0xff, .len = 2048, }; The CAN drivers' xmit() function are calling can_dev_dropped_skb() to check that the skb is valid, unfortunately under above conditions, the malicious packet is able to go through can_dev_dropped_skb() checks: 1. the skb->protocol is set to ETH_P_CANXL which is valid (the function does not check the actual device capabilities). 2. the length is a valid CAN XL length. And so, sun4ican_start_xmit() receives a CAN XL frame which it is not able to correctly handle and will thus misinterpret it as a CAN frame. This can result in a buffer overflow. The driver will consume cf->len as-is with no further checks on this line: dlc = cf->len; Here, cf->len corresponds to the flags field of the CAN XL frame. In our previous example, we set canxl_frame->flags to 0xff. Because the maximum expected length is 8, a buffer overflow of 247 bytes occurs a couple line below when doing: for (i = 0; i < dlc; i++) writel(cf->data[i], priv->base + (dreg + i * 4)); Populate net_device_ops->ndo_change_mtu() to ensure that the interface's MTU can not be set to anything bigger than CAN_MTU. By fixing the root cause, this prevents the buffer overflow.
Product status
0738eff14d817a02ab082c392c96a1613006f158 before 063539db42203b29d5aa2adf0cae3d68c646a6b6
0738eff14d817a02ab082c392c96a1613006f158 before 4f382cc887adca8478b9d3e6b81aa6698a95fff4
0738eff14d817a02ab082c392c96a1613006f158 before 60463a1c138900494cb3adae41142a11cd8feb3c
0738eff14d817a02ab082c392c96a1613006f158 before a61ff7ac93270d20ca426c027d6d01c8ac8e904c
0738eff14d817a02ab082c392c96a1613006f158 before 2e423e1990f3972cbea779883fef52c2f2acb858
0738eff14d817a02ab082c392c96a1613006f158 before de77841652e57afbc46e9e1dbf51ee364fc008e1
0738eff14d817a02ab082c392c96a1613006f158 before 7f7b21026a6febdb749f6f6f950427245aa86cce
0738eff14d817a02ab082c392c96a1613006f158 before 61da0bd4102c459823fbe6b8b43b01fb6ace4a22
4.4
Any version before 4.4
5.4.300
5.10.245
5.15.194
6.1.155
6.6.109
6.12.50
6.16.10
6.17
References
git.kernel.org/...c/063539db42203b29d5aa2adf0cae3d68c646a6b6
git.kernel.org/...c/4f382cc887adca8478b9d3e6b81aa6698a95fff4
git.kernel.org/...c/60463a1c138900494cb3adae41142a11cd8feb3c
git.kernel.org/...c/a61ff7ac93270d20ca426c027d6d01c8ac8e904c
git.kernel.org/...c/2e423e1990f3972cbea779883fef52c2f2acb858
git.kernel.org/...c/de77841652e57afbc46e9e1dbf51ee364fc008e1
git.kernel.org/...c/7f7b21026a6febdb749f6f6f950427245aa86cce
git.kernel.org/...c/61da0bd4102c459823fbe6b8b43b01fb6ace4a22
