Merge bitcoin/bitcoin#27896: Remove the syscall sandbox

32e2ffc39374f61bb2435da507f285459985df9e Remove the syscall sandbox (fanquake)

Pull request description:

  After initially being merged in #20487, it's no-longer clear that an internal syscall sandboxing mechanism is something that Bitcoin Core should have/maintain, especially when compared to better maintained/supported alterantives, i.e [firejail](https://github.com/netblue30/firejail).

  There is more related discussion in #24771.

  Note that given where it's used, the sandbox also gets dragged into the kernel.

  If it's removed, this should not require any sort of deprecation, as this was only ever an opt-in, experimental feature.

  Closes #24771.

ACKs for top commit:
  davidgumberg:
     crACK https://github.com/bitcoin/bitcoin/pull/27896/commits/32e2ffc39374f61bb2435da507f285459985df9e
  achow101:
    ACK 32e2ffc39374f61bb2435da507f285459985df9e
  dergoegge:
    ACK 32e2ffc39374f61bb2435da507f285459985df9e

Tree-SHA512: 8cf71c5623bb642cb515531d4a2545d806e503b9d57bfc15a996597632b06103d60d985fd7f843a3c1da6528bc38d0298d6b8bcf0be6f851795a8040d71faf16

1 files changed, 0 insertions, 37 deletions

diff --git a/configure.ac b/configure.ac
index f4368053a0..29ac8e3805 100644
--- a/configure.ac
+++ b/configure.ac
@@ -96,12 +96,6 @@ case $host in
   ;;
 esac
 
-AC_ARG_WITH([seccomp],
-  [AS_HELP_STRING([--with-seccomp],
-  [enable experimental syscall sandbox feature (-sandbox), default is yes if seccomp-bpf is detected under Linux x86_64])],
-  [seccomp_found=$withval],
-  [seccomp_found=auto])
-
 AC_ARG_ENABLE([c++20],
   [AS_HELP_STRING([--enable-c++20],
   [enable compilation in c++20 mode (disabled by default)])],
@@ -1540,36 +1534,6 @@ if test "$use_external_signer" != "no"; then
 fi
 AM_CONDITIONAL([ENABLE_EXTERNAL_SIGNER], [test "$use_external_signer" = "yes"])
 
-dnl Do not compile with syscall sandbox support when compiling under the sanitizers.
-dnl The sanitizers introduce use of syscalls that are not typically used in bitcoind
-dnl (such as execve when the sanitizers execute llvm-symbolizer).
-if test "$use_sanitizers" != ""; then
-  AC_MSG_WARN([Specifying --with-sanitizers forces --without-seccomp since the sanitizers introduce use of syscalls not allowed by the bitcoind syscall sandbox (-sandbox=<mode>).])
-  seccomp_found=no
-fi
-if test "$seccomp_found" != "no"; then
-  AC_MSG_CHECKING([for seccomp-bpf (Linux x86-64)])
-  AC_PREPROC_IFELSE([AC_LANG_PROGRAM([[
-      @%:@include <linux/seccomp.h>
-    ]], [[
-      #if !defined(__x86_64__)
-      #  error Syscall sandbox is an experimental feature currently available only under Linux x86-64.
-      #endif
-    ]])],[
-      AC_MSG_RESULT([yes])
-      seccomp_found="yes"
-      AC_DEFINE([USE_SYSCALL_SANDBOX], [1], [Define this symbol to build with syscall sandbox support.])
-    ],[
-      AC_MSG_RESULT([no])
-      seccomp_found="no"
-  ])
-fi
-dnl Currently only enable -sandbox=<mode> feature if seccomp is found.
-dnl In the future, sandboxing could be also be supported with other
-dnl sandboxing mechanisms besides seccomp.
-use_syscall_sandbox=$seccomp_found
-AM_CONDITIONAL([ENABLE_SYSCALL_SANDBOX], [test "$use_syscall_sandbox" != "no"])
-
 dnl Check for reduced exports
 if test "$use_reduce_exports" = "yes"; then
   AX_CHECK_COMPILE_FLAG([-fvisibility=hidden], [CORE_CXXFLAGS="$CORE_CXXFLAGS -fvisibility=hidden"],
@@ -2009,7 +1973,6 @@ echo
 echo "Options used to compile and link:"
 echo "  external signer = $use_external_signer"
 echo "  multiprocess    = $build_multiprocess"
-echo "  with experimental syscall sandbox support = $use_syscall_sandbox"
 echo "  with libs       = $build_bitcoin_libs"
 echo "  with wallet     = $enable_wallet"
 if test "$enable_wallet" != "no"; then