aarch64 support for seccomp-bpf sandbox
Also resort and tidy syscall list. Based on patches by Jakub Jelen
bz#2361; ok dtucker@
diff --git a/sandbox-seccomp-filter.c b/sandbox-seccomp-filter.c
index b6f6258..badfee2 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 @@
/* 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),
- SC_ALLOW(clock_gettime),
-#ifdef __NR_time /* not defined on EABI ARM */
- SC_ALLOW(time),
#endif
- SC_ALLOW(read),
- SC_ALLOW(write),
- SC_ALLOW(close),
-#ifdef __NR_shutdown /* not defined on archs that go via socketcall(2) */
- SC_ALLOW(shutdown),
+#ifdef __NR_stat64
+ SC_DENY(stat64, EACCES),
#endif
+
+ /* Syscalls to permit */
+#ifdef __NR_brk
SC_ALLOW(brk),
- SC_ALLOW(poll),
-#ifdef __NR__newselect
- SC_ALLOW(_newselect),
-#else
- SC_ALLOW(select),
#endif
+#ifdef __NR_clock_gettime
+ SC_ALLOW(clock_gettime),
+#endif
+#ifdef __NR_close
+ SC_ALLOW(close),
+#endif
+#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__
- SC_ALLOW(mremap),
- SC_ALLOW(exit),
+#ifdef __NR_mmap2
+ SC_ALLOW(mmap2),
#endif
+#ifdef __NR_mremap
+ SC_ALLOW(mremap),
+#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),
};