[PATCH v2 1/2] rsaenh: Don't crash when decrypting empty strings

[Jakub Petrzilka]

From: Jakub Petrzilka

Some applications apparently attempts to decrypt empty strings in some edge cases which currently lead to page fault.

Wine-Bug https://bugs.winehq.org/show_bug.cgi?id=57042
---
 dlls/rsaenh/rsaenh.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dlls/rsaenh/rsaenh.c b/dlls/rsaenh/rsaenh.c
index f854e35dfdf..25aba026152 100644
--- a/dlls/rsaenh/rsaenh.c
+++ b/dlls/rsaenh/rsaenh.c
@@ -2798,7 +2798,8 @@ BOOL WINAPI RSAENH_CPDecrypt(HCRYPTPROV hProv, HCRYPTKEY hKey, HCRYPTHASH hHash,
             memcpy(in, out, pCryptKey->dwBlockLen);
         }
         if (Final) {
-            if (pbData[*pdwDataLen-1] &&
+            if (*pdwDataLen >=1 &&
+             pbData[*pdwDataLen-1] &&
              pbData[*pdwDataLen-1] <= pCryptKey->dwBlockLen &&
              pbData[*pdwDataLen-1] <= *pdwDataLen) {
                 BOOL padOkay = TRUE;