Description
In the Linux kernel, the following vulnerability has been resolved: can: etas_es58x: 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 etas_es58x 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, es58x_start_xmit() receives a CAN XL frame which it is not able to correctly handle and will thus misinterpret it as a CAN(FD) frame. This can result in a buffer overflow. For example, using the es581.4 variant, the frame will be dispatched to es581_4_tx_can_msg(), go through the last check at the beginning of this function: if (can_is_canfd_skb(skb)) return -EMSGSIZE; and reach this line: memcpy(tx_can_msg->data, cf->data, 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! Populate net_device_ops->ndo_change_mtu() to ensure that the interface's MTU can not be set to anything bigger than CAN_MTU or CANFD_MTU (depending on the device capabilities). By fixing the root cause, this prevents the buffer overflow.
Product status
8537257874e949a59c834cecfd5a063e11b64b0b before 72de0facc50afdb101fb7197d880407f1abfc77f
8537257874e949a59c834cecfd5a063e11b64b0b before c4e582e686c4d683c87f2b4a316385b3d81d370f
8537257874e949a59c834cecfd5a063e11b64b0b before cbc1de71766f326a44bb798aeae4a7ef4a081cc9
8537257874e949a59c834cecfd5a063e11b64b0b before b26cccd87dcddc47b450a40f3b1ac3fe346efcff
8537257874e949a59c834cecfd5a063e11b64b0b before e587af2c89ecc6382c518febea52fa9ba81e47c0
8537257874e949a59c834cecfd5a063e11b64b0b before 38c0abad45b190a30d8284a37264d2127a6ec303
5.13
Any version before 5.13
5.15.194
6.1.155
6.6.109
6.12.50
6.16.10
6.17
References
git.kernel.org/...c/72de0facc50afdb101fb7197d880407f1abfc77f
git.kernel.org/...c/c4e582e686c4d683c87f2b4a316385b3d81d370f
git.kernel.org/...c/cbc1de71766f326a44bb798aeae4a7ef4a081cc9
git.kernel.org/...c/b26cccd87dcddc47b450a40f3b1ac3fe346efcff
git.kernel.org/...c/e587af2c89ecc6382c518febea52fa9ba81e47c0
git.kernel.org/...c/38c0abad45b190a30d8284a37264d2127a6ec303
