Juan Lang : crypt32: Implement PFXIsPFXBlob.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 2ffc042ebf50351a8bb02dbedf2d9d032b5a8382
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=2ffc042ebf50351a8bb02dbedf2d9d032b5a8382

Author: Juan Lang <juan.lang at gmail.com>
Date:   Tue Jan 27 09:00:03 2009 -0800

crypt32: Implement PFXIsPFXBlob.

---

 dlls/crypt32/crypt32.spec |    1 +
 dlls/crypt32/decode.c     |   35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/dlls/crypt32/crypt32.spec b/dlls/crypt32/crypt32.spec
index fcffab2..3f5db87 100644
--- a/dlls/crypt32/crypt32.spec
+++ b/dlls/crypt32/crypt32.spec
@@ -219,6 +219,7 @@
 @ stdcall PFXExportCertStore(ptr ptr ptr long)
 @ stdcall PFXExportCertStoreEx(ptr ptr ptr ptr long)
 @ stub PFXImportCertStore
+@ stdcall PFXIsPFXBlob(ptr)
 @ stub RegCreateHKCUKeyExU
 @ stub RegCreateKeyExU
 @ stub RegDeleteValueU
diff --git a/dlls/crypt32/decode.c b/dlls/crypt32/decode.c
index d917d9b..bc0ee17 100644
--- a/dlls/crypt32/decode.c
+++ b/dlls/crypt32/decode.c
@@ -5511,3 +5511,38 @@ BOOL WINAPI CryptDecodeObjectEx(DWORD dwCertEncodingType, LPCSTR lpszStructType,
     TRACE_(crypt)("returning %d\n", ret);
     return ret;
 }
+
+BOOL WINAPI PFXIsPFXBlob(CRYPT_DATA_BLOB *pPFX)
+{
+    BOOL ret;
+
+    TRACE("(%p)\n", pPFX);
+
+    /* A PFX blob is an asn.1-encoded sequence, consisting of at least a
+     * version integer of length 1 (3 encoded byes) and at least one other
+     * datum (two encoded bytes), plus at least two bytes for the outer
+     * sequence.  Thus, even an empty PFX blob is at least 7 bytes in length.
+     */
+    if (pPFX->cbData < 7)
+        ret = FALSE;
+    else if (pPFX->pbData[0] == ASN_SEQUENCE)
+    {
+        DWORD len;
+
+        if ((ret = CRYPT_GetLengthIndefinite(pPFX->pbData, pPFX->cbData, &len)))
+        {
+            BYTE lenLen = GET_LEN_BYTES(pPFX->pbData[1]);
+
+            /* Need at least three bytes for the integer version */
+            if (pPFX->cbData < 1 + lenLen + 3)
+                ret = FALSE;
+            else if (pPFX->pbData[1 + lenLen] != ASN_INTEGER || /* Tag */
+             pPFX->pbData[1 + lenLen + 1] != 1 ||          /* Definite length */
+             pPFX->pbData[1 + lenLen + 2] != 3)            /* PFX version */
+                ret = FALSE;
+        }
+    }
+    else
+        ret = FALSE;
+    return ret;
+}