From 7faabbeb1d735069a2fd1e24e20b2543306a0e28 Mon Sep 17 00:00:00 2001 From: Natanael Copa Date: Tue, 24 Mar 2020 11:31:41 +0100 Subject: [PATCH] _dbus_generate_random_bytes: use getrandom(2) Use getrandom(2) and fall back to /dev/urandom if it is missing or if it fails some any reason. This solves problem where dbus-uuidgen is called from a chroot which lacks /dev/urandom. Signed-off-by: Natanael Copa --- cmake/ConfigureChecks.cmake | 2 ++ cmake/config.h.cmake | 2 ++ configure.ac | 3 ++- dbus/dbus-sysdeps-unix.c | 23 ++++++++++++++++++++--- 4 files changed, 26 insertions(+), 4 deletions(-) diff --git a/cmake/ConfigureChecks.cmake b/cmake/ConfigureChecks.cmake index a9a5fc90..f920c75f 100644 --- a/cmake/ConfigureChecks.cmake +++ b/cmake/ConfigureChecks.cmake @@ -26,6 +26,7 @@ check_include_file(strings.h HAVE_STRINGS_H) check_include_file(syslog.h HAVE_SYSLOG_H) check_include_files("stdint.h;sys/types.h;sys/event.h" HAVE_SYS_EVENT_H) check_include_file(sys/inotify.h HAVE_SYS_INOTIFY_H) +check_include_file(sys/random.h HAVE_SYS_RANDOM_H) check_include_file(sys/resource.h HAVE_SYS_RESOURCE_H) check_include_file(sys/stat.h HAVE_SYS_STAT_H) check_include_file(sys/types.h HAVE_SYS_TYPES_H) @@ -62,6 +63,7 @@ check_symbol_exists(inotify_init1 "sys/inotify.h" HAVE_INOTIFY_INIT1) check_symbol_exists(SCM_RIGHTS "sys/types.h;sys/socket.h;sys/un.h" HAVE_UNIX_FD_PASSING) check_symbol_exists(prctl "sys/prctl.h" HAVE_PRCTL) check_symbol_exists(raise "signal.h" HAVE_RAISE) +check_symbol_exists(getrandom "sys/random.h" HAVE_GETRANDOM) check_symbol_exists(getrlimit "sys/resource.h;sys/time.h" HAVE_GETRLIMIT) check_symbol_exists(prlimit "sys/resource.h;sys/time.h" HAVE_PRLIMIT) check_symbol_exists(setrlimit "sys/resource.h;sys/time.h" HAVE_SETRLIMIT) diff --git a/cmake/config.h.cmake b/cmake/config.h.cmake index 11191821..10388fce 100644 --- a/cmake/config.h.cmake +++ b/cmake/config.h.cmake @@ -128,6 +128,7 @@ #cmakedefine HAVE_SYS_EVENTS_H #cmakedefine HAVE_SYS_INOTIFY_H #cmakedefine HAVE_SYS_PRCTL_H +#cmakedefine HAVE_SYS_RANDOM_H 1 #cmakedefine HAVE_SYS_RESOURCE_H #cmakedefine HAVE_SYS_STAT_H @@ -205,6 +206,7 @@ #cmakedefine HAVE_ACCEPT4 1 #cmakedefine HAVE_DIRFD 1 #cmakedefine HAVE_INOTIFY_INIT1 1 +#cmakedefine HAVE_GETRANDOM 1 #cmakedefine HAVE_GETRLIMIT 1 #cmakedefine HAVE_PRLIMIT 1 #cmakedefine HAVE_SETRLIMIT 1 diff --git a/configure.ac b/configure.ac index a1ba877a..c9f50b0f 100644 --- a/configure.ac +++ b/configure.ac @@ -619,7 +619,7 @@ AC_DEFINE_UNQUOTED([DBUS_USE_SYNC], [$have_sync], [Use the gcc __sync extension] AC_SEARCH_LIBS(socket,[socket network]) AC_CHECK_FUNC(gethostbyname,,[AC_CHECK_LIB(nsl,gethostbyname)]) -AC_CHECK_FUNCS([vsnprintf vasprintf nanosleep usleep setenv clearenv unsetenv socketpair getgrouplist fpathconf setrlimit poll setlocale localeconv strtoll strtoull issetugid getresuid setresuid getrlimit prlimit]) +AC_CHECK_FUNCS([vsnprintf vasprintf nanosleep usleep setenv clearenv unsetenv socketpair getgrouplist fpathconf setrlimit poll setlocale localeconv strtoll strtoull issetugid getresuid setresuid getrlimit getrandom prlimit]) AC_CHECK_HEADERS([syslog.h]) if test "x$ac_cv_header_syslog_h" = "xyes"; then @@ -667,6 +667,7 @@ fi AC_CHECK_HEADERS(sys/resource.h) AC_CHECK_HEADERS([sys/time.h]) +AC_CHECK_HEADERS([sys/random.h]) AC_CHECK_HEADERS(dirent.h) diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c index e8cd5b33..44f7711e 100644 --- a/dbus/dbus-sysdeps-unix.c +++ b/dbus/dbus-sysdeps-unix.c @@ -80,6 +80,9 @@ #ifdef HAVE_ALLOCA_H #include #endif +#ifdef HAVE_SYS_RANDOM_H +#include +#endif #ifdef HAVE_ADT #include @@ -3158,12 +3161,26 @@ _dbus_generate_random_bytes (DBusString *str, int n_bytes, DBusError *error) { - int old_len; + int old_len = _dbus_string_get_length (str); int fd; int result; +#ifdef HAVE_GETRANDOM + char *buffer; + + if (!_dbus_string_lengthen (str, n_bytes)) + { + _DBUS_SET_OOM (error); + return FALSE; + } + + buffer = _dbus_string_get_data_len (str, old_len, n_bytes); + result = getrandom (buffer, n_bytes, GRND_NONBLOCK); - old_len = _dbus_string_get_length (str); - fd = -1; + if (result == n_bytes) + return TRUE; + + _dbus_string_set_length (str, old_len); +#endif /* note, urandom on linux will fall back to pseudorandom */ fd = open ("/dev/urandom", O_RDONLY); -- 2.26.0