From d9685121ff6d57b8797411f3cb123884a4b96e30 Mon Sep 17 00:00:00 2001
From: Darren Tucker <dtucker@dtucker.net>
Date: Sat, 11 Feb 2023 12:32:19 +1100
Subject: [PATCH] Improve seccomp compat on older systems.

Check if flags to mmap and madvise are defined before using them.
Should fix problems building on older Linux systems that don't have
these.  bz#3537, with & ok djm@.
---
 sandbox-seccomp-filter.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/sandbox-seccomp-filter.c b/sandbox-seccomp-filter.c
index 78c266231..23b40b643 100644
--- a/sandbox-seccomp-filter.c
+++ b/sandbox-seccomp-filter.c
@@ -189,10 +189,14 @@
 #endif /* __NR_futex || __NR_futex_time64 */
 
 #if defined(__NR_mmap) || defined(__NR_mmap2)
+# ifdef MAP_FIXED_NOREPLACE
+#  define SC_MMAP_FLAGS MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_FIXED_NOREPLACE
+# else
+#  define SC_MMAP_FLAGS MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED
+# endif /* MAP_FIXED_NOREPLACE */
 /* Use this for both __NR_mmap and __NR_mmap2 variants */
 # define SC_MMAP(_nr) \
-	SC_DENY_UNLESS_ARG_MASK(_nr, 3, \
-	    MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_FIXED_NOREPLACE, EINVAL), \
+	SC_DENY_UNLESS_ARG_MASK(_nr, 3, SC_MMAP_FLAGS, EINVAL), \
 	SC_ALLOW_ARG_MASK(_nr, 2, PROT_READ|PROT_WRITE|PROT_NONE)
 #endif /* __NR_mmap || __NR_mmap2 */
 
@@ -308,11 +312,21 @@ static const struct sock_filter preauth_insns[] = {
 #endif
 #ifdef __NR_madvise
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_NORMAL),
+# ifdef MADV_FREE
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_FREE),
+# endif
+# ifdef MADV_DONTNEED
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_DONTNEED),
+# endif
+# ifdef MADV_DONTFORK
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_DONTFORK),
+# endif
+# ifdef MADV_DONTDUMP
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_DONTDUMP),
+# endif
+# ifdef MADV_WIPEONFORK
 	SC_ALLOW_ARG(__NR_madvise, 2, MADV_WIPEONFORK),
+# endif
 	SC_DENY(__NR_madvise, EINVAL),
 #endif
 #ifdef __NR_mmap