Re: [PATCH] tracing: do not leak kernel addresses

On Thu, 26 Jul 2018 09:52:11 -0700 Nick Desaulniers ndesaulniers@google.com wrote:

See the section "Kernel addresses" in Documentation/security/self-protection. IIRC, the issue is that a process may have CAP_SYSLOG but not necessarily CAP_SYS_ADMIN (so it can read dmesg, but not necessarily issue a sysctl to change kptr_restrict), get compromised and used to leak kernel addresses, which can then be used to defeat KASLR.

But the code doesn't go to dmesg. It's only available via /sys/kernel/debug/tracing/printk_formats which is only available via root. Nobody else has access to that directory.

-- Steve