Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Pull request

# gpg: Signature made Wed 24 Jun 2020 11:01:57 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  block/nvme: support nested aio_poll()
  block/nvme: keep BDRVNVMeState pointer in NVMeQueuePair
  block/nvme: clarify that free_req_queue is protected by q->lock
  block/nvme: switch to a NVMeRequest freelist
  block/nvme: don't access CQE after moving cq.head
  block/nvme: drop tautologous assertion
  block/nvme: poll queues without q->lock
  check-block: enable iotests with SafeStack
  configure: add flags to support SafeStack
  coroutine: add check for SafeStack in sigaltstack
  coroutine: support SafeStack in ucontext backend
  minikconf: explicitly set encoding to UTF-8

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/configure b/configure
index ba88fd1824..ae8737d5a2 100755
--- a/configure
+++ b/configure
@@ -307,6 +307,7 @@ audio_win_int=""
 libs_qga=""
 debug_info="yes"
 stack_protector=""
+safe_stack=""
 use_containers="yes"
 gdb_bin=$(command -v "gdb-multiarch" || command -v "gdb")
 
@@ -1287,6 +1288,10 @@ for opt do
   ;;
   --disable-stack-protector) stack_protector="no"
   ;;
+  --enable-safe-stack) safe_stack="yes"
+  ;;
+  --disable-safe-stack) safe_stack="no"
+  ;;
   --disable-curses) curses="no"
   ;;
   --enable-curses) curses="yes"
@@ -1829,6 +1834,8 @@ disabled with --disable-FEATURE, default is enabled if available:
   debug-tcg       TCG debugging (default is disabled)
   debug-info      debugging information
   sparse          sparse checker
+  safe-stack      SafeStack Stack Smash Protection. Depends on
+                  clang/llvm >= 3.7 and requires coroutine backend ucontext.
 
   gnutls          GNUTLS cryptography support
   nettle          nettle cryptography support
@@ -5573,6 +5580,67 @@ if test "$debug_stack_usage" = "yes"; then
   fi
 fi
 
+##################################################
+# SafeStack
+
+
+if test "$safe_stack" = "yes"; then
+cat > $TMPC << EOF
+int main(int argc, char *argv[])
+{
+#if ! __has_feature(safe_stack)
+#error SafeStack Disabled
+#endif
+    return 0;
+}
+EOF
+  flag="-fsanitize=safe-stack"
+  # Check that safe-stack is supported and enabled.
+  if compile_prog "-Werror $flag" "$flag"; then
+    # Flag needed both at compilation and at linking
+    QEMU_CFLAGS="$QEMU_CFLAGS $flag"
+    QEMU_LDFLAGS="$QEMU_LDFLAGS $flag"
+  else
+    error_exit "SafeStack not supported by your compiler"
+  fi
+  if test "$coroutine" != "ucontext"; then
+    error_exit "SafeStack is only supported by the coroutine backend ucontext"
+  fi
+else
+cat > $TMPC << EOF
+int main(int argc, char *argv[])
+{
+#if defined(__has_feature)
+#if __has_feature(safe_stack)
+#error SafeStack Enabled
+#endif
+#endif
+    return 0;
+}
+EOF
+if test "$safe_stack" = "no"; then
+  # Make sure that safe-stack is disabled
+  if ! compile_prog "-Werror" ""; then
+    # SafeStack was already enabled, try to explicitly remove the feature
+    flag="-fno-sanitize=safe-stack"
+    if ! compile_prog "-Werror $flag" "$flag"; then
+      error_exit "Configure cannot disable SafeStack"
+    fi
+    QEMU_CFLAGS="$QEMU_CFLAGS $flag"
+    QEMU_LDFLAGS="$QEMU_LDFLAGS $flag"
+  fi
+else # "$safe_stack" = ""
+  # Set safe_stack to yes or no based on pre-existing flags
+  if compile_prog "-Werror" ""; then
+    safe_stack="no"
+  else
+    safe_stack="yes"
+    if test "$coroutine" != "ucontext"; then
+      error_exit "SafeStack is only supported by the coroutine backend ucontext"
+    fi
+  fi
+fi
+fi
 
 ##########################################
 # check if we have open_by_handle_at
@@ -6765,6 +6833,7 @@ echo "sparse enabled    $sparse"
 echo "strip binaries    $strip_opt"
 echo "profiler          $profiler"
 echo "static build      $static"
+echo "safe stack        $safe_stack"
 if test "$darwin" = "yes" ; then
     echo "Cocoa support     $cocoa"
 fi
@@ -8370,6 +8439,10 @@ if test "$ccache_cpp2" = "yes"; then
   echo "export CCACHE_CPP2=y" >> $config_host_mak
 fi
 
+if test "$safe_stack" = "yes"; then
+  echo "CONFIG_SAFESTACK=y" >> $config_host_mak
+fi
+
 # If we're using a separate build tree, set it up now.
 # DIRS are directories which we simply mkdir in the build tree;
 # LINKS are things to symlink back into the source tree