dict: Get random seed from system PRNG

CMakeLists.txt

@@ -137,6 +137,7 @@ if (NOT MSVC)
 	check_include_files(fcntl.h HAVE_FCNTL_H)
 	check_function_exists(fpclass HAVE_FPCLASS)
 	check_function_exists(ftime HAVE_FTIME)
+        check_function_exists(getentropy HAVE_GETENTROPY)
 	check_function_exists(gettimeofday HAVE_GETTIMEOFDAY)
 	check_include_files(inttypes.h HAVE_INTTYPES_H)
 	check_function_exists(isascii HAVE_ISASCII)
@@ -151,6 +152,7 @@ if (NOT MSVC)
 	check_function_exists(stat HAVE_STAT)
 	check_include_files(stdint.h HAVE_STDINT_H)
 	check_include_files(sys/mman.h HAVE_SYS_MMAN_H)
+        check_include_files(sys/random.h HAVE_SYS_RANDOM_H)
 	check_include_files(sys/select.h HAVE_SYS_SELECT_H)
 	check_include_files(sys/socket.h HAVE_SYS_SOCKET_H)
 	check_include_files(sys/stat.h HAVE_SYS_STAT_H)
@@ -358,6 +360,8 @@ endif()
 if(WIN32)
 	target_link_libraries(LibXml2 PRIVATE ws2_32)
 	set(WINSOCK_LIBS "-lws2_32")
+	target_link_libraries(LibXml2 PRIVATE bcrypt)
+        set(CRYPTO_LIBS "-lbcrypt")
 endif()
 
 if(LIBXML2_WITH_ICONV)
@@ -641,7 +645,7 @@ if(LIBXML2_WITH_PYTHON)
 	configure_file(python/setup.py.in setup.py @ONLY)
 endif()
 
-set(NON_PC_LIBS "${THREAD_LIBS} ${ICONV_LIBS} ${LIBM} ${WINSOCK_LIBS}")
+set(NON_PC_LIBS "${THREAD_LIBS} ${ICONV_LIBS} ${LIBM} ${WINSOCK_LIBS} ${CRYPTO_LIBS}")
 list(APPEND XML_PC_LIBS "${NON_PC_LIBS}")
 list(APPEND XML_PRIVATE_LIBS "${NON_PC_LIBS}")
 list(REMOVE_DUPLICATES XML_PC_LIBS)

config.h.cmake.in

@@ -22,6 +22,9 @@
 /* Define to 1 if you have the `ftime' function. */
 #cmakedefine HAVE_FTIME 1
 
+/* Define to 1 if you have the `getentropy' function. */
+#cmakedefine HAVE_GETENTROPY 1
+
 /* Define to 1 if you have the `gettimeofday' function. */
 #cmakedefine HAVE_GETTIMEOFDAY 1
 
@@ -72,6 +75,9 @@
 /* Define to 1 if you have the <sys/mman.h> header file. */
 #cmakedefine HAVE_SYS_MMAN_H 1
 
+/* Define to 1 if you have the <sys/random.h> header file. */
+#cmakedefine HAVE_SYS_RANDOM_H 1
+
 /* Define to 1 if you have the <sys/select.h> header file. */
 #cmakedefine HAVE_SYS_SELECT_H 1
 

configure.ac

@@ -300,6 +300,7 @@ AC_CHECK_HEADERS([sys/mman.h])
 AC_CHECK_HEADERS([sys/socket.h netinet/in.h arpa/inet.h netdb.h])
 AC_CHECK_HEADERS([sys/select.h poll.h])
 AC_CHECK_HEADERS([sys/time.h sys/timeb.h])
+AC_CHECK_HEADERS([sys/random.h])
 AC_CHECK_HEADERS([dl.h dlfcn.h])
 AC_CHECK_HEADERS([glob.h])
 AM_CONDITIONAL(WITH_GLOB, test "$ac_cv_header_glob_h" = "yes")
@@ -310,7 +311,7 @@ dnl
 AC_TYPE_UINT32_T
 
 dnl Checks for library functions.
-AC_CHECK_FUNCS([gettimeofday ftime stat isascii mmap munmap])
+AC_CHECK_FUNCS([getentropy gettimeofday ftime isascii stat mmap munmap])
 
 AH_VERBATIM([HAVE_MUNMAP_AFTER],[/* mmap() is no good without munmap() */
 #if defined(HAVE_MMAP) && !defined(HAVE_MUNMAP)
@@ -1104,6 +1105,15 @@ else
 fi
 AC_SUBST(WITH_ICU)
 
+dnl
+dnl Crypto libraries
+dnl
+case "$host" in
+    *-*-mingw*)
+        CRYPTO_LIBS="-lbcrypt"
+        ;;
+esac
+
 if test "$with_coverage" = "yes" && test "${GCC}" = "yes"
 then
     echo Enabling code coverage for GCC
@@ -1115,7 +1125,7 @@ fi
 
 XML_LIBS="-lxml2"
 XML_LIBTOOLLIBS="libxml2.la"
-NON_PC_LIBS="${THREAD_LIBS} ${ICONV_LIBS} ${LIBM} ${NET_LIBS}"
+NON_PC_LIBS="${THREAD_LIBS} ${ICONV_LIBS} ${LIBM} ${NET_LIBS} ${CRYPTO_LIBS}"
 XML_PC_LIBS="${XML_PC_LIBS} ${NON_PC_LIBS}"
 XML_PRIVATE_LIBS="${XML_PRIVATE_LIBS} ${NON_PC_LIBS}"
 XML_PRIVATE_CFLAGS="${XML_PRIVATE_CFLAGS} ${THREAD_CFLAGS} ${ICONV_CFLAGS}"

dict.c

@@ -19,9 +19,20 @@
 #define IN_LIBXML
 #include "libxml.h"
 
+#include <errno.h>
 #include <limits.h>
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
+#ifdef HAVE_SYS_RANDOM_H
+#include <sys/random.h>
+#endif
+
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <bcrypt.h>
+#endif
 
 #include "private/dict.h"
 #include "private/threads.h"
@@ -916,16 +927,42 @@ static XML_THREAD_LOCAL unsigned localRngState[2];
 ATTRIBUTE_NO_SANITIZE_INTEGER
 void
 xmlInitRandom(void) {
-    int var;
-
     xmlInitMutex(&xmlRngMutex);
 
-    /* TODO: Get seed values from system PRNG */
+    {
+#ifdef _WIN32
+        NTSTATUS status;
 
-    globalRngState[0] = (unsigned) time(NULL) ^
-                        HASH_ROL((unsigned) ((size_t) &xmlInitRandom & 0xFFFFFFFF), 8);
-    globalRngState[1] = HASH_ROL((unsigned) ((size_t) &xmlRngMutex & 0xFFFFFFFF), 16) ^
-                        HASH_ROL((unsigned) ((size_t) &var & 0xFFFFFFFF), 24);
+        status = BCryptGenRandom(NULL, (unsigned char *) globalRngState,
+                                 sizeof(globalRngState),
+                                 BCRYPT_USE_SYSTEM_PREFERRED_RNG);
+        if (!BCRYPT_SUCCESS(status)) {
+            fprintf(stderr, "libxml2: BCryptGenRandom failed with "
+                    "error code %lu\n", GetLastError());
+            abort();
+        }
+#elif defined(HAVE_GETENTROPY)
+        while (1) {
+            if (getentropy(globalRngState, sizeof(globalRngState)) == 0)
+                break;
+
+            if (errno != EINTR) {
+                fprintf(stderr, "libxml2: getentropy failed with "
+                        "error code %d\n", errno);
+                abort();
+            }
+        }
+#else
+        int var;
+
+        globalRngState[0] =
+                (unsigned) time(NULL) ^
+                HASH_ROL((unsigned) ((size_t) &xmlInitRandom & 0xFFFFFFFF), 8);
+        globalRngState[1] =
+                HASH_ROL((unsigned) ((size_t) &xmlRngMutex & 0xFFFFFFFF), 16) ^
+                HASH_ROL((unsigned) ((size_t) &var & 0xFFFFFFFF), 24);
+#endif
+    }
 }
 
 void