[libav-devel] [PATCH] random_seed: use bcrypt instead of the old wincrypt API

[Martin Storsjö]

From: Steve Lhomme <rob...@ycbcr.xyz>

Remove the wincrypt API calls since we don't support XP anymore and
bcrypt is available since Vista, even on Windows Store builds.
---
Now with avutil_extralibs sorted alphabetically, and James' extended
configure check included.
---
 configure               |  7 ++++---
 libavutil/random_seed.c | 19 ++++++++++---------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/configure b/configure
index 3c7b6a0981..465fdcfb6d 100755
--- a/configure
+++ b/configure
@@ -1703,12 +1703,12 @@ SYSTEM_FUNCS="
 "
 
 SYSTEM_LIBRARIES="
+    bcrypt
     sdl
     vaapi_1
     vaapi_drm
     vaapi_x11
     vdpau_x11
-    wincrypt
 "
 
 TOOLCHAIN_FEATURES="
@@ -2610,7 +2610,7 @@ avdevice_extralibs="libm_extralibs"
 avformat_extralibs="libm_extralibs"
 avfilter_extralibs="pthreads_extralibs libm_extralibs"
 avresample_extralibs="libm_extralibs"
-avutil_extralibs="clock_gettime_extralibs cuda_extralibs cuvid_extralibs 
d3d11va_extralibs libm_extralibs libmfx_extralibs nanosleep_extralibs 
pthreads_extralibs user32_extralibs vaapi_extralibs vaapi_drm_extralibs 
vaapi_x11_extralibs vdpau_x11_extralibs wincrypt_extralibs"
+avutil_extralibs="bcrypt_extralibs clock_gettime_extralibs cuda_extralibs 
cuvid_extralibs d3d11va_extralibs libm_extralibs libmfx_extralibs 
nanosleep_extralibs pthreads_extralibs user32_extralibs vaapi_extralibs 
vaapi_drm_extralibs vaapi_x11_extralibs vdpau_x11_extralibs"
 swscale_extralibs="libm_extralibs"
 
 # programs
@@ -4579,9 +4579,10 @@ check_header windows.h
 # so we also check that atomics actually work here
 check_builtin stdatomic stdatomic.h "atomic_int foo; atomic_store(&foo, 0)"
 
+check_lib bcrypt   "windows.h bcrypt.h"   BCryptGenRandom      -lbcrypt &&
+    check_cpp_condition bcrypt bcrypt.h "defined BCRYPT_RNG_ALGORITHM"
 check_lib ole32    "windows.h"            CoTaskMemFree        -lole32
 check_lib shell32  "windows.h shellapi.h" CommandLineToArgvW   -lshell32
-check_lib wincrypt "windows.h wincrypt.h" CryptGenRandom       -ladvapi32
 check_lib psapi    "windows.h psapi.h"    GetProcessMemoryInfo -lpsapi
 
 check_struct "sys/time.h sys/resource.h" "struct rusage" ru_maxrss
diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c
index 089d883916..388cb401ba 100644
--- a/libavutil/random_seed.c
+++ b/libavutil/random_seed.c
@@ -23,9 +23,9 @@
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
-#if HAVE_WINCRYPT
+#if HAVE_BCRYPT
 #include <windows.h>
-#include <wincrypt.h>
+#include <bcrypt.h>
 #endif
 #include <fcntl.h>
 #include <math.h>
@@ -96,13 +96,14 @@ uint32_t av_get_random_seed(void)
 {
     uint32_t seed;
 
-#if HAVE_WINCRYPT
-    HCRYPTPROV provider;
-    if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL,
-                            CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
-        BOOL ret = CryptGenRandom(provider, sizeof(seed), (PBYTE) &seed);
-        CryptReleaseContext(provider, 0);
-        if (ret)
+#if HAVE_BCRYPT
+    BCRYPT_ALG_HANDLE algo_handle;
+    NTSTATUS ret = BCryptOpenAlgorithmProvider(&algo_handle, 
BCRYPT_RNG_ALGORITHM,
+                                               MS_PRIMITIVE_PROVIDER, 0);
+    if (BCRYPT_SUCCESS(ret)) {
+        NTSTATUS ret = BCryptGenRandom(algo_handle, (UCHAR*)&seed, 
sizeof(seed), 0);
+        BCryptCloseAlgorithmProvider(algo_handle, 0);
+        if (BCRYPT_SUCCESS(ret))
             return seed;
     }
 #endif
-- 
2.15.1 (Apple Git-101)

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