Commit 2e253cbc authored Jan 23, 2017 by Colin Cross

Allow tkill

tkill and tgkill are syscalls that do not have glibc wrappers, but
they are required in order to send a signal to a specific thread.
Non-android software may call them directly with syscall().  Bionic
provides a wrapper for tgkill, so seccomp allows it, but not for
tkill.  Add tkill to the whitelist.

This can be reproduced with:
sleep 1000 & sleep 1 ; strace -p $!
then hit ctrl-C, and the shell will print "Bad system call" because
the strace process died with SIGSYS

Bug: 34586922
Test: repro case is fixed
Change-Id: Ib6962a967f2cc757f2906de7905e75e1b6d6f39f

parent 47afc6b6

init/seccomp.cpp

+6 −0

Original line number	Diff line number	Diff line
		@@ -170,6 +170,9 @@ bool set_seccomp_filter() {
		// Needed for trusty
		AllowSyscall(f, __NR_syncfs);

		// Needed for strace
		AllowSyscall(f, __NR_tkill); // __NR_tkill

		// Needed for kernel to restart syscalls
		AllowSyscall(f, __NR_restart_syscall);

		@@ -204,6 +207,9 @@ bool set_seccomp_filter() {
		// Syscalls needed to run GFXBenchmark
		AllowSyscall(f, 190); // __NR_vfork

		// Needed for strace
		AllowSyscall(f, 238); // __NR_tkill

		// Needed for kernel to restart syscalls
		AllowSyscall(f, 0); // __NR_restart_syscall