From f3ad68446455acbe562e0057931e6256b8b991e8 Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Mon, 22 Jul 2019 11:59:00 +0200 Subject: executor: drop CAP_SYS_NICE A process with CAP_SYS_NICE can bring kernel down by asking for too high SCHED_DEADLINE priority, as the result rcu and other system services that use kernel threads will stop functioning. Some parameters for SCHED_DEADLINE should be OK, but we don't have means to enforce values of indirect syscall arguments. Peter Zijlstra proposed sysctl_deadline_period_{min,max} which could be used to enfore safe limits without droppping CAP_SYS_NICE, but we don't have it yet. See the following bug for details: https://groups.google.com/forum/#!topic/syzkaller-bugs/G6Wl_PKPIWI --- pkg/csource/generated.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'pkg/csource/generated.go') diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go index eb863e8e1..58ccf11b0 100644 --- a/pkg/csource/generated.go +++ b/pkg/csource/generated.go @@ -4441,7 +4441,7 @@ static void drop_caps(void) cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) fail("capget failed"); - const int drop = (1 << CAP_SYS_PTRACE); + const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; -- cgit mrf-deployment