fuzz: disable all deps when building with oss-fuzz

The fuzz targets are intended to be fast and only target systemd
code, so they don't need to call out to any dependencies. They also
shouldn't depend on shared libraries outside of libc, so we disable
every dependency when compiling against oss-fuzz. This also
simplifies the upstream build environment significantly.

meson.build

@@ -779,10 +779,11 @@ if not libcap.found()
 endif
 
 libmount = dependency('mount',
-                      version : '>= 2.30')
+                      version : '>= 2.30',
+                      required : not ossfuzz)
 
 want_seccomp = get_option('seccomp')
-if want_seccomp != 'false'
+if want_seccomp != 'false' and not ossfuzz
         libseccomp = dependency('libseccomp',
                                 version : '>= 2.3.1',
                                 required : want_seccomp == 'true')
@@ -795,7 +796,7 @@ conf.set10('HAVE_SECCOMP', have)
 m4_defines += have ? ['-DHAVE_SECCOMP'] : []
 
 want_selinux = get_option('selinux')
-if want_selinux != 'false'
+if want_selinux != 'false' and not ossfuzz
         libselinux = dependency('libselinux',
                                 version : '>= 2.1.9',
                                 required : want_selinux == 'true')
@@ -808,7 +809,7 @@ conf.set10('HAVE_SELINUX', have)
 m4_defines += have ? ['-DHAVE_SELINUX'] : []
 
 want_apparmor = get_option('apparmor')
-if want_apparmor != 'false'
+if want_apparmor != 'false' and not ossfuzz
         libapparmor = dependency('libapparmor',
                                  required : want_apparmor == 'true')
         have = libapparmor.found()
@@ -828,7 +829,7 @@ endif
 want_polkit = get_option('polkit')
 install_polkit = false
 install_polkit_pkla = false
-if want_polkit != 'false'
+if want_polkit != 'false' and not ossfuzz
         install_polkit = true
 
         libpolkit = dependency('polkit-gobject-1',
@@ -841,7 +842,7 @@ endif
 conf.set10('ENABLE_POLKIT', install_polkit)
 
 want_acl = get_option('acl')
-if want_acl != 'false'
+if want_acl != 'false' and not ossfuzz
         libacl = cc.find_library('acl', required : want_acl == 'true')
         have = libacl.found()
 else
@@ -852,7 +853,7 @@ conf.set10('HAVE_ACL', have)
 m4_defines += have ? ['-DHAVE_ACL'] : []
 
 want_audit = get_option('audit')
-if want_audit != 'false'
+if want_audit != 'false' and not ossfuzz
         libaudit = dependency('audit', required : want_audit == 'true')
         have = libaudit.found()
 else
@@ -862,7 +863,7 @@ endif
 conf.set10('HAVE_AUDIT', have)
 
 want_blkid = get_option('blkid')
-if want_blkid != 'false'
+if want_blkid != 'false' and not ossfuzz
         libblkid = dependency('blkid', required : want_blkid == 'true')
         have = libblkid.found()
 else
@@ -872,7 +873,7 @@ endif
 conf.set10('HAVE_BLKID', have)
 
 want_kmod = get_option('kmod')
-if want_kmod != 'false'
+if want_kmod != 'false' and not ossfuzz
         libkmod = dependency('libkmod',
                              version : '>= 15',
                              required : want_kmod == 'true')
@@ -884,7 +885,7 @@ endif
 conf.set10('HAVE_KMOD', have)
 
 want_pam = get_option('pam')
-if want_pam != 'false'
+if want_pam != 'false' and not ossfuzz
         libpam = cc.find_library('pam', required : want_pam == 'true')
         libpam_misc = cc.find_library('pam_misc', required : want_pam == 'true')
         have = libpam.found() and libpam_misc.found()
@@ -897,7 +898,7 @@ conf.set10('HAVE_PAM', have)
 m4_defines += have ? ['-DHAVE_PAM'] : []
 
 want_microhttpd = get_option('microhttpd')
-if want_microhttpd != 'false'
+if want_microhttpd != 'false' and not ossfuzz
         libmicrohttpd = dependency('libmicrohttpd',
                                    version : '>= 0.9.33',
                                    required : want_microhttpd == 'true')
@@ -910,7 +911,7 @@ conf.set10('HAVE_MICROHTTPD', have)
 m4_defines += have ? ['-DHAVE_MICROHTTPD'] : []
 
 want_libcryptsetup = get_option('libcryptsetup')
-if want_libcryptsetup != 'false'
+if want_libcryptsetup != 'false' and not ossfuzz
         libcryptsetup = dependency('libcryptsetup',
                                    version : '>= 1.6.0',
                                    required : want_libcryptsetup == 'true')
@@ -922,7 +923,7 @@ endif
 conf.set10('HAVE_LIBCRYPTSETUP', have)
 
 want_libcurl = get_option('libcurl')
-if want_libcurl != 'false'
+if want_libcurl != 'false' and not ossfuzz
         libcurl = dependency('libcurl',
                              version : '>= 7.32.0',
                              required : want_libcurl == 'true')
@@ -940,7 +941,7 @@ if want_libidn == 'true' and want_libidn2 == 'true'
         error('libidn and libidn2 cannot be requested simultaneously')
 endif
 
-if want_libidn != 'false' and want_libidn2 != 'true'
+if want_libidn != 'false' and want_libidn2 != 'true' and not ossfuzz
         libidn = dependency('libidn',
                             required : want_libidn == 'true')
         have = libidn.found()
@@ -950,7 +951,7 @@ else
 endif
 conf.set10('HAVE_LIBIDN', have)
 m4_defines += have ? ['-DHAVE_LIBIDN'] : []
-if not have and want_libidn2 != 'false'
+if not have and want_libidn2 != 'false' and not ossfuzz
         # libidn is used for both libidn and libidn2 objects
         libidn = dependency('libidn2',
                             required : want_libidn2 == 'true')
@@ -962,7 +963,7 @@ conf.set10('HAVE_LIBIDN2', have)
 m4_defines += have ? ['-DHAVE_LIBIDN2'] : []
 
 want_libiptc = get_option('libiptc')
-if want_libiptc != 'false'
+if want_libiptc != 'false' and not ossfuzz
         libiptc = dependency('libiptc',
                              required : want_libiptc == 'true')
         have = libiptc.found()
@@ -974,7 +975,7 @@ conf.set10('HAVE_LIBIPTC', have)
 m4_defines += have ? ['-DHAVE_LIBIPTC'] : []
 
 want_qrencode = get_option('qrencode')
-if want_qrencode != 'false'
+if want_qrencode != 'false' and not ossfuzz
         libqrencode = dependency('libqrencode',
                                  required : want_qrencode == 'true')
         have = libqrencode.found()
@@ -985,7 +986,7 @@ endif
 conf.set10('HAVE_QRENCODE', have)
 
 want_gcrypt = get_option('gcrypt')
-if want_gcrypt != 'false'
+if want_gcrypt != 'false' and not ossfuzz
         libgcrypt = cc.find_library('gcrypt', required : want_gcrypt == 'true')
         libgpg_error = cc.find_library('gpg-error', required : want_gcrypt == 'true')
         have = libgcrypt.found() and libgpg_error.found()
@@ -1000,7 +1001,7 @@ endif
 conf.set10('HAVE_GCRYPT', have)
 
 want_gnutls = get_option('gnutls')
-if want_gnutls != 'false'
+if want_gnutls != 'false' and not ossfuzz
         libgnutls = dependency('gnutls',
                                version : '>= 3.1.4',
                                required : want_gnutls == 'true')
@@ -1012,7 +1013,7 @@ endif
 conf.set10('HAVE_GNUTLS', have)
 
 want_elfutils = get_option('elfutils')
-if want_elfutils != 'false'
+if want_elfutils != 'false' and not ossfuzz
         libdw = dependency('libdw',
                            required : want_elfutils == 'true')
         have = libdw.found()
@@ -1023,7 +1024,7 @@ endif
 conf.set10('HAVE_ELFUTILS', have)
 
 want_zlib = get_option('zlib')
-if want_zlib != 'false'
+if want_zlib != 'false' and not ossfuzz
         libz = dependency('zlib',
                           required : want_zlib == 'true')
         have = libz.found()
@@ -1034,7 +1035,7 @@ endif
 conf.set10('HAVE_ZLIB', have)
 
 want_bzip2 = get_option('bzip2')
-if want_bzip2 != 'false'
+if want_bzip2 != 'false' and not ossfuzz
         libbzip2 = cc.find_library('bz2',
                                    required : want_bzip2 == 'true')
         have = libbzip2.found()
@@ -1045,7 +1046,7 @@ endif
 conf.set10('HAVE_BZIP2', have)
 
 want_xz = get_option('xz')
-if want_xz != 'false'
+if want_xz != 'false' and not ossfuzz
         libxz = dependency('liblzma',
                            required : want_xz == 'true')
         have = libxz.found()
@@ -1056,7 +1057,7 @@ endif
 conf.set10('HAVE_XZ', have)
 
 want_lz4 = get_option('lz4')
-if want_lz4 != 'false'
+if want_lz4 != 'false' and not ossfuzz
         liblz4 = dependency('liblz4',
                             required : want_lz4 == 'true')
         have = liblz4.found()
@@ -1067,7 +1068,7 @@ endif
 conf.set10('HAVE_LZ4', have)
 
 want_xkbcommon = get_option('xkbcommon')
-if want_xkbcommon != 'false'
+if want_xkbcommon != 'false' and not ossfuzz
         libxkbcommon = dependency('xkbcommon',
                                   version : '>= 0.3.0',
                                   required : want_xkbcommon == 'true')
@@ -1079,7 +1080,7 @@ endif
 conf.set10('HAVE_XKBCOMMON', have)
 
 want_glib = get_option('glib')
-if want_glib != 'false'
+if want_glib != 'false' and not ossfuzz
         libglib =    dependency('glib-2.0',
                                 version : '>= 2.22.0',
                                 required : want_glib == 'true')
@@ -1098,7 +1099,7 @@ endif
 conf.set10('HAVE_GLIB', have)
 
 want_dbus = get_option('dbus')
-if want_dbus != 'false'
+if want_dbus != 'false' and not ossfuzz
         libdbus = dependency('dbus-1',
                              version : '>= 1.3.2',
                              required : want_dbus == 'true')
@@ -1110,6 +1111,9 @@ endif
 conf.set10('HAVE_DBUS', have)
 
 default_dnssec = get_option('default-dnssec')
+if ossfuzz
+        default_dnssec = 'no'
+endif
 if default_dnssec != 'no' and conf.get('HAVE_GCRYPT') == 0
         message('default-dnssec cannot be set to yes or allow-downgrade when gcrypt is disabled. Setting default-dnssec to no.')
         default_dnssec = 'no'

scripts/oss-fuzz.sh

@@ -20,7 +20,7 @@ set -ex
 
 export LC_CTYPE=C.UTF-8
 
-meson $WORK -Doss-fuzz=true -Db_lundef=false -Dseccomp=false -Dlz4=false -Dlibiptc=false -Dlibidn=false
+meson $WORK -Doss-fuzz=true -Db_lundef=false
 ninja -C $WORK fuzzers
 
 # get DNS packet corpus