Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

[mirror_qemu.git] / crypto / random-platform.c

diff --git a/crypto/random-platform.c b/crypto/random-platform.c
index 82b755afad179c42a0f9e404be47aa3e36636a6f..66624106fe19b9f60d7b822d9511e9140fcfebd6 100644 (file)
--- a/crypto/random-platform.c
+++ b/crypto/random-platform.c
@@ -21,44 +21,94 @@
 #include "qemu/osdep.h"
 
 #include "crypto/random.h"
+#include "qapi/error.h"
 
-int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
-                         size_t buflen G_GNUC_UNUSED,
-                         Error **errp)
-{
-    int fd;
-    int ret = -1;
-    int got;
+#ifdef _WIN32
+#include <wincrypt.h>
+static HCRYPTPROV hCryptProv;
+#else
+# ifdef CONFIG_GETRANDOM
+#  include <sys/random.h>
+# endif
+/* This is -1 for getrandom(), or a file handle for /dev/{u,}random.  */
+static int fd;
+#endif
 
-    /* TBD perhaps also add support for BSD getentropy / Linux
-     * getrandom syscalls directly */
-    fd = open("/dev/urandom", O_RDONLY);
+int qcrypto_random_init(Error **errp)
+{
+#ifdef _WIN32
+    if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
+                             CRYPT_SILENT | CRYPT_VERIFYCONTEXT)) {
+        error_setg_win32(errp, GetLastError(),
+                         "Unable to create cryptographic provider");
+        return -1;
+    }
+#else
+# ifdef CONFIG_GETRANDOM
+    if (getrandom(NULL, 0, 0) == 0) {
+        /* Use getrandom() */
+        fd = -1;
+        return 0;
+    }
+    /* Fall through to /dev/urandom case.  */
+# endif
+    fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
     if (fd == -1 && errno == ENOENT) {
-        fd = open("/dev/random", O_RDONLY);
+        fd = open("/dev/random", O_RDONLY | O_CLOEXEC);
     }
-
     if (fd < 0) {
-        error_setg(errp, "No /dev/urandom or /dev/random found");
+        error_setg_errno(errp, errno, "No /dev/urandom or /dev/random");
         return -1;
     }
+#endif
+    return 0;
+}
 
-    while (buflen > 0) {
-        got = read(fd, buf, buflen);
-        if (got < 0) {
-            error_setg_errno(errp, errno,
-                             "Unable to read random bytes");
-            goto cleanup;
-        } else if (!got) {
-            error_setg(errp,
-                       "Unexpected EOF reading random bytes");
-            goto cleanup;
+int qcrypto_random_bytes(void *buf,
+                         size_t buflen,
+                         Error **errp)
+{
+#ifdef _WIN32
+    if (!CryptGenRandom(hCryptProv, buflen, buf)) {
+        error_setg_win32(errp, GetLastError(),
+                         "Unable to read random bytes");
+        return -1;
+    }
+#else
+# ifdef CONFIG_GETRANDOM
+    if (likely(fd < 0)) {
+        while (1) {
+            ssize_t got = getrandom(buf, buflen, 0);
+            if (likely(got == buflen)) {
+                return 0;
+            }
+            if (got >= 0) {
+                buflen -= got;
+                buf += got;
+            } else if (errno != EINTR) {
+                error_setg_errno(errp, errno, "getrandom");
+                return -1;
+            }
         }
-        buflen -= got;
-        buf += got;
     }
-
-    ret = 0;
- cleanup:
-    close(fd);
-    return ret;
+    /* Fall through to /dev/urandom case.  */
+# endif
+    while (1) {
+        ssize_t got = read(fd, buf, buflen);
+        if (likely(got == buflen)) {
+            return 0;
+        }
+        if (got > 0) {
+            buflen -= got;
+            buf += got;
+        } else if (got == 0) {
+            error_setg(errp, "Unexpected EOF reading random bytes");
+            return -1;
+        } else if (errno != EINTR) {
+            error_setg_errno(errp, errno, "Unable to read random bytes");
+            return -1;
+        }
+    }
+#endif
+    return 0;
 }