CVE-2023-53011: NULL Pointer Dereference

In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: enable all safety features by default

In the original implementation of dwmac5 commit 8bf993a5877e ("net: stmmac: Add support for DWMAC5 and implement Safety Features") all safety features were enabled by default.

Later it seems some implementations didn't have support for all the features, so in commit 5ac712dcdfef ("net: stmmac: enable platform specific safety features") the safety_feat_cfg structure was added to the callback and defined for some platforms to selectively enable these safety features.

The problem is that only certain platforms were given that software support. If the automotive safety package bit is set in the hardware features register the safety feature callback is called for the platform, and for platforms that didn't get a safety_feat_cfg defined this results in the following NULL pointer dereference:

[ 7.933303] Call trace: [ 7.935812] dwmac5_safety_feat_config+0x20/0x170 [stmmac] [ 7.941455] __stmmac_open+0x16c/0x474 [stmmac] [ 7.946117] stmmac_open+0x38/0x70 [stmmac] [ 7.950414] __dev_open+0x100/0x1dc [ 7.954006] __dev_change_flags+0x18c/0x204 [ 7.958297] dev_change_flags+0x24/0x6c [ 7.962237] do_setlink+0x2b8/0xfa4 [ 7.965827] __rtnl_newlink+0x4ec/0x840 [ 7.969766] rtnl_newlink+0x50/0x80 [ 7.973353] rtnetlink_rcv_msg+0x12c/0x374 [ 7.977557] netlink_rcv_skb+0x5c/0x130 [ 7.981500] rtnetlink_rcv+0x18/0x2c [ 7.985172] netlink_unicast+0x2e8/0x340 [ 7.989197] netlink_sendmsg+0x1a8/0x420 [ 7.993222] ____sys_sendmsg+0x218/0x280 [ 7.997249] ___sys_sendmsg+0xac/0x100 [ 8.001103] __sys_sendmsg+0x84/0xe0 [ 8.004776] __arm64_sys_sendmsg+0x24/0x30 [ 8.008983] invoke_syscall+0x48/0x114 [ 8.012840] el0_svc_common.constprop.0+0xcc/0xec [ 8.017665] do_el0_svc+0x38/0xb0 [ 8.021071] el0_svc+0x2c/0x84 [ 8.024212] el0t_64_sync_handler+0xf4/0x120 [ 8.028598] el0t_64_sync+0x190/0x194

Go back to the original behavior, if the automotive safety package is found to be supported in hardware enable all the features unless safety_feat_cfg is passed in saying this particular platform only supports a subset of the features.