sys_linux: allow rseq in seccomp filter

Libc 2.35 will use rseq syscalls [1][2] by default and thereby
break chrony in seccomp isolation.

[1]: https://www.efficios.com/blog/2019/02/08/linux-restartable-sequences/
[2]: https://sourceware.org/pipermail/libc-alpha/2022-February/136040.html

Tested-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Reviewed-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>

diff --git a/sys_linux.c b/sys_linux.c
index 9cab2efaa7b96ee3a0a4c7923575601af2619268..cc3c9311d306e5a1d9153848b2def6670ab92a31 100644 (file)
--- a/sys_linux.c
+++ b/sys_linux.c
@@ -497,6 +497,9 @@ SYS_Linux_EnableSystemCallFilter(int level, SYS_ProcessContext context)
     SCMP_SYS(getrlimit),
     SCMP_SYS(getuid),
     SCMP_SYS(getuid32),
+#ifdef __NR_rseq
+    SCMP_SYS(rseq),
+#endif
     SCMP_SYS(rt_sigaction),
     SCMP_SYS(rt_sigreturn),
     SCMP_SYS(rt_sigprocmask),