mlxsw: spectrum_acl_tcam: Fix NULL pointer dereference in error path

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum_acl_tcam: Fix NULL pointer dereference in error path When calling mlxsw_sp_acl_tcam_region_destroy() from an error path after failing to attach the region to an ACL group, we hit a NULL pointer dereference upon 'region->group->tcam' [1]. Fix by retrieving the 'tcam' pointer using mlxsw_sp_acl_to_tcam(). [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] RIP: 0010:mlxsw_sp_acl_tcam_region_destroy+0xa0/0xd0 [...] Call Trace: mlxsw_sp_acl_tcam_vchunk_get+0x88b/0xa20 mlxsw_sp_acl_tcam_ventry_add+0x25/0xe0 mlxsw_sp_acl_rule_add+0x47/0x240 mlxsw_sp_flower_replace+0x1a9/0x1d0 tc_setup_cb_add+0xdc/0x1c0 fl_hw_replace_filter+0x146/0x1f0 fl_change+0xc17/0x1360 tc_new_tfilter+0x472/0xb90 rtnetlink_rcv_msg+0x313/0x3b0 netlink_rcv_skb+0x58/0x100 netlink_unicast+0x244/0x390 netlink_sendmsg+0x1e4/0x440 ____sys_sendmsg+0x164/0x260 ___sys_sendmsg+0x9a/0xe0 __sys_sendmsg+0x7a/0xc0 do_syscall_64+0x40/0xe0 entry_SYSCALL_64_after_hwframe+0x63/0x6b

References

• https://git.kernel.org/stable/c/75fa2d8b3c0175b519c99ace54ab8474cfd0077e
• https://git.kernel.org/stable/c/817840d125a370626895df269c50c923b79b0a39
• https://git.kernel.org/stable/c/d0a1efe417c97a1e9b914056ee6b86f1ef75fe1f
• https://git.kernel.org/stable/c/efeb7dfea8ee10cdec11b6b6ba4e405edbe75809