[PATCH] setupx.dll16: Avoid strcmp() result truncation (Coverity)

[Marcus Meissner]

Hi,

strcmp() might return a full 32bit wide difference in optimized
strcmp cases, so we need to avoid truncating the upper 16 bits.

(mysql security flaw resulting from such a truncation:

https://community.rapid7.com/community/metasploit/blog/2012/06/11/cve-2012-2122-a-tragically-comedic-security-flaw-in-mysql
)

Ciao, Marcus
---
 dlls/setupx.dll16/virtcopy.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/dlls/setupx.dll16/virtcopy.c b/dlls/setupx.dll16/virtcopy.c
index a718ac9..773202e 100644
--- a/dlls/setupx.dll16/virtcopy.c
+++ b/dlls/setupx.dll16/virtcopy.c
@@ -591,9 +591,17 @@ static void VCP_UI_RegisterProgressClass(void)
 static RETERR16 VCP_UI_NodeCompare(LPVIRTNODE vn1, LPVIRTNODE vn2)
 {
     LPCSTR file1, file2;
+    int ret;
     file1 = vsmGetStringRawName16(vn1->vfsSrc.vhstrFileName);
     file2 = vsmGetStringRawName16(vn2->vfsSrc.vhstrFileName);
-    return (RETERR16)strcmp(file1, file2);
+
+    ret = strcmp(file1, file2);
+    /* Looks too complicated, but in optimized strcpy we might get
+     * a 32bit wide difference and would truncate it to 16 bit, so
+     * erronously returning equality. */
+    if (ret < 0) return -1;
+    if (ret > 0) return  1;
+    return 0;
 }
 
 static RETERR16 VCP_UI_CopyStart(void)
-- 
1.7.3.4