Code injection

The sysrq_sysctl_handler function in kernel/sysctl.c in the Linux kernel before 2.6.39 does not require the CAP_SYS_ADMIN capability to modify the dmesg_restrict value, which allows local users to bypass intended access restrictions and read the kernel ring buffer by leveraging root privileges, as demonstrated by a root user in a Linux Containers (aka LXC) environment.