aarch64 support for seccomp-bpf sandbox

Also resort and tidy syscall list. Based on patches by Jakub Jelen
bz#2361; ok dtucker@

1 files changed, 85 insertions, 20 deletions

diff --git a/sandbox-seccomp-filter.c b/sandbox-seccomp-filter.c
index b6f6258f2..badfee2ec 100644
--- a/sandbox-seccomp-filter.c
+++ b/sandbox-seccomp-filter.c
@@ -43,6 +43,7 @@
 #include <sys/resource.h>
 #include <sys/prctl.h>
 
+#include <linux/net.h>
 #include <linux/audit.h>
 #include <linux/filter.h>
 #include <linux/seccomp.h>
@@ -79,6 +80,16 @@
 #define SC_ALLOW(_nr) \
         BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 1), \
         BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
+#define SC_ALLOW_ARG(_nr, _arg_nr, _arg_val) \
+        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, __NR_ ## _nr, 0, 3), \
+        /* load first syscall argument */ \
+        BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \
+            offsetof(struct seccomp_data, args[(_arg_nr)])), \
+        BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (_arg_val), 0, 1), \
+        BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW), \
+        /* reload syscall number; all rules expect it in accumulator */ \
+        BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \
+                offsetof(struct seccomp_data, nr))
 
 /* Syscall filtering set for preauth. */
 static const struct sock_filter preauth_insns[] = {
@@ -90,45 +101,99 @@ static const struct sock_filter preauth_insns[] = {
         /* Load the syscall number for checking. */
         BPF_STMT(BPF_LD+BPF_W+BPF_ABS,
                 offsetof(struct seccomp_data, nr)),
+
+        /* Syscalls to non-fatally deny */
+#ifdef __NR_fstat
+        SC_DENY(fstat, EACCES),
+#endif
+#ifdef __NR_fstat64
+        SC_DENY(fstat64, EACCES),
+#endif
+#ifdef __NR_open
         SC_DENY(open, EACCES),
+#endif
+#ifdef __NR_openat
+        SC_DENY(openat, EACCES),
+#endif
+#ifdef __NR_newfstatat
+        SC_DENY(newfstatat, EACCES),
+#endif
+#ifdef __NR_stat
         SC_DENY(stat, EACCES),
-        SC_ALLOW(getpid),
-        SC_ALLOW(gettimeofday),
+#endif
+#ifdef __NR_stat64
+        SC_DENY(stat64, EACCES),
+#endif
+
+        /* Syscalls to permit */
+#ifdef __NR_brk
+        SC_ALLOW(brk),
+#endif
+#ifdef __NR_clock_gettime
         SC_ALLOW(clock_gettime),
-#ifdef __NR_time /* not defined on EABI ARM */
-        SC_ALLOW(time),
 #endif
-        SC_ALLOW(read),
-        SC_ALLOW(write),
+#ifdef __NR_close
         SC_ALLOW(close),
-#ifdef __NR_shutdown /* not defined on archs that go via socketcall(2) */
-        SC_ALLOW(shutdown),
 #endif
-        SC_ALLOW(brk),
-        SC_ALLOW(poll),
-#ifdef __NR__newselect
-        SC_ALLOW(_newselect),
-#else
-        SC_ALLOW(select),
+#ifdef __NR_exit
+        SC_ALLOW(exit),
+#endif
+#ifdef __NR_exit_group
+        SC_ALLOW(exit_group),
+#endif
+#ifdef __NR_getpid
+        SC_ALLOW(getpid),
 #endif
+#ifdef __NR_gettimeofday
+        SC_ALLOW(gettimeofday),
+#endif
+#ifdef __NR_madvise
         SC_ALLOW(madvise),
-#ifdef __NR_mmap2 /* EABI ARM only has mmap2() */
-        SC_ALLOW(mmap2),
 #endif
 #ifdef __NR_mmap
         SC_ALLOW(mmap),
 #endif
-#ifdef __dietlibc__
+#ifdef __NR_mmap2
+        SC_ALLOW(mmap2),
+#endif
+#ifdef __NR_mremap
         SC_ALLOW(mremap),
-        SC_ALLOW(exit),
 #endif
+#ifdef __NR_munmap
         SC_ALLOW(munmap),
-        SC_ALLOW(exit_group),
+#endif
+#ifdef __NR__newselect
+        SC_ALLOW(_newselect),
+#endif
+#ifdef __NR_poll
+        SC_ALLOW(poll),
+#endif
+#ifdef __NR_read
+        SC_ALLOW(read),
+#endif
 #ifdef __NR_rt_sigprocmask
         SC_ALLOW(rt_sigprocmask),
-#else
+#endif
+#ifdef __NR_select
+        SC_ALLOW(select),
+#endif
+#ifdef __NR_shutdown
+        SC_ALLOW(shutdown),
+#endif
+#ifdef __NR_sigprocmask
         SC_ALLOW(sigprocmask),
 #endif
+#ifdef __NR_time
+        SC_ALLOW(time),
+#endif
+#ifdef __NR_write
+        SC_ALLOW(write),
+#endif
+#ifdef __NR_socketcall
+        SC_ALLOW_ARG(socketcall, 0, SYS_SHUTDOWN),
+#endif
+
+        /* Default deny */
         BPF_STMT(BPF_RET+BPF_K, SECCOMP_FILTER_FAIL),
 };