Aric Stewart : wintrust: GetSignedMsgFromCabFile looks for signinfo at the beginning of the cab.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: d962939290f407d925c12b2fb3f4d3cdd0d015da
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=d962939290f407d925c12b2fb3...

Author: Aric Stewart <aric(a)codeweavers.com>
Date:   Thu Jun 25 16:59:46 2009 +0900

wintrust: GetSignedMsgFromCabFile looks for signinfo at the beginning of the cab.

Discussed with Juan Lang, We could look for the signinfo at the 
beginning of the cab and restore the file pointer afterward.

This allows IE7 to read the signing information from downloaded ActiveX 
controls.

---

 dlls/wintrust/crypt.c |   35 ++++-------------------------------
 1 files changed, 4 insertions(+), 31 deletions(-)

diff --git a/dlls/wintrust/crypt.c b/dlls/wintrust/crypt.c
index e01a230..d9fa563 100644
--- a/dlls/wintrust/crypt.c
+++ b/dlls/wintrust/crypt.c
@@ -1121,36 +1121,6 @@ static BOOL WINTRUST_GetSignedMsgFromCabFile(SIP_SUBJECTINFO *pSubjectInfo,
     TRACE("(%p %p %d %p %p)\n", pSubjectInfo, pdwEncodingType, dwIndex,
           pcbSignedDataMsg, pbSignedDataMsg);
 
-    /*
-     * FIXME: I just noticed that I am memorizing the initial file pointer
-     * offset and restoring it before reading in the rest of the header
-     * information in the cabinet.  Perhaps that's correct -- that is, perhaps
-     * this API is supposed to support "streaming" cabinets which are embedded
-     * in other files, or cabinets which begin at file offsets other than zero.
-     * Otherwise, I should instead go to the absolute beginning of the file.
-     * (Either way, the semantics of wine's FDICopy require me to leave the
-     * file pointer where it is afterwards -- If Windows does not do so, we
-     * ought to duplicate the native behavior in the FDIIsCabinet API, not here.
-     *
-     * So, the answer lies in Windows; will native cabinet.dll recognize a
-     * cabinet "file" embedded in another file?  Note that cabextract.c does
-     * support this, which implies that Microsoft's might.  I haven't tried it
-     * yet so I don't know.  ATM, most of wine's FDI cabinet routines (except
-     * this one) would not work in this way.  To fix it, we could just make the
-     * various references to absolute file positions in the code relative to an
-     * initial "beginning" offset.  Because the FDICopy API doesn't take a
-     * file-handle like this one, we would therein need to search through the
-     * file for the beginning of the cabinet (as we also do in cabextract.c).
-     * Note that this limits us to a maximum of one cabinet per. file: the first.
-     *
-     * So, in summary: either the code below is wrong, or the rest of fdi.c is
-     * wrong... I cannot imagine that both are correct ;)  One of these flaws
-     * should be fixed after determining the behavior on Windows.   We ought
-     * to check both FDIIsCabinet and FDICopy for the right behavior.
-     *
-     * -gmt
-     */
-
     /* get basic offset & size info */
     base_offset = SetFilePointer(pSubjectInfo->hFile, 0L, NULL, SEEK_CUR);
 
@@ -1162,7 +1132,7 @@ static BOOL WINTRUST_GetSignedMsgFromCabFile(SIP_SUBJECTINFO *pSubjectInfo,
 
     cabsize = SetFilePointer(pSubjectInfo->hFile, 0L, NULL, SEEK_CUR);
     if ((cabsize == -1) || (base_offset == -1) ||
-     (SetFilePointer(pSubjectInfo->hFile, base_offset, NULL, SEEK_SET) == INVALID_SET_FILE_POINTER))
+     (SetFilePointer(pSubjectInfo->hFile, 0, NULL, SEEK_SET) == INVALID_SET_FILE_POINTER))
     {
         TRACE("seek error\n");
         return FALSE;
@@ -1267,6 +1237,7 @@ static BOOL WINTRUST_GetSignedMsgFromCabFile(SIP_SUBJECTINFO *pSubjectInfo,
      NULL) || dwRead != cert_size)
     {
         ERR("couldn't read cert\n");
+        SetFilePointer(pSubjectInfo->hFile, base_offset, NULL, SEEK_SET);
         return FALSE;
     }
     /* The encoding of the files I've seen appears to be in ASN.1
@@ -1274,6 +1245,8 @@ static BOOL WINTRUST_GetSignedMsgFromCabFile(SIP_SUBJECTINFO *pSubjectInfo,
      * always is.
      */
     *pdwEncodingType = X509_ASN_ENCODING | PKCS_7_ASN_ENCODING;
+    /* Restore base offset */
+    SetFilePointer(pSubjectInfo->hFile, base_offset, NULL, SEEK_SET);
     return TRUE;
 }