Re: Bug#787644: libwmf: CVE-2015-0848: heap overflow when decoding BMP images
Hi,
On Tue, Jun 16, 2015 at 06:26:31AM +0200, Salvatore Bonaccorso wrote:
> Hi,
>
> A second CVE was assigned for a further issue:
>
> http://www.openwall.com/lists/oss-security/2015/06/16/4
> (CVE-2015-4588).
Attached debdiff fixes the two CVEs on squeeze-lts. Since sid,jessie and
wheezy ship basically the same versions it should easily apply there as
well.
With the patches applied I couldn't reproduce the crashes anymore as
descibed at:
http://seclists.org/oss-sec/2015/q2/597
I'd appreciate any comments / reviews before releasing the DLA.
Cheers,
-- Guido
diff --git a/debian/changelog b/debian/changelog
index b130ed9..bd3b0f0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,14 @@
+libwmf (0.2.8.4-6.2+deb6u1) squeeze-lts; urgency=medium
+
+ * CVE-2015-4588: Add RLE Decoding check
+ Fix taken from Redhat BZ
+ https://bugzilla.redhat.com/show_bug.cgi?id=1227243
+ * CVE-2015-0848: Only DecodeImage if pixel is one byte
+ Fix taken from Redhat BZ
+ https://bugzilla.redhat.com/show_bug.cgi?id=1227243
+
+ -- Guido Günther <agx@sigxcpu.org> Fri, 19 Jun 2015 13:48:03 +0200
+
libwmf (0.2.8.4-6.1) unstable; urgency=high
* Non-maintainer upload.
diff --git a/src/ipa/ipa.h b/src/ipa/ipa.h
index d050a7e..3003540 100644
--- a/src/ipa/ipa.h
+++ b/src/ipa/ipa.h
@@ -48,7 +48,7 @@ static int ReadBlobByte (BMPSource*);
static unsigned short ReadBlobLSBShort (BMPSource*);
static unsigned long ReadBlobLSBLong (BMPSource*);
static long TellBlob (BMPSource*);
-static void DecodeImage (wmfAPI*,wmfBMP*,BMPSource*,unsigned int,unsigned char*);
+static int DecodeImage (wmfAPI*,wmfBMP*,BMPSource*,unsigned int,unsigned char*);
static void ReadBMPImage (wmfAPI*,wmfBMP*,BMPSource*);
static int ExtractColor (wmfAPI*,wmfBMP*,wmfRGB*,unsigned int,unsigned int);
static void SetColor (wmfAPI*,wmfBMP*,wmfRGB*,unsigned char,unsigned int,unsigned int);
diff --git a/src/ipa/ipa/bmp.h b/src/ipa/ipa/bmp.h
index 29eee34..7751a36 100644
--- a/src/ipa/ipa/bmp.h
+++ b/src/ipa/ipa/bmp.h
@@ -859,7 +859,7 @@ static long TellBlob (BMPSource* src)
%
%
*/
-static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int compression,unsigned char* pixels)
+static int DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int compression,unsigned char* pixels)
{ int byte;
int count;
int i;
@@ -870,12 +870,14 @@ static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int com
U32 u;
unsigned char* q;
+ unsigned char* end;
for (u = 0; u < ((U32) bmp->width * (U32) bmp->height); u++) pixels[u] = 0;
byte = 0;
x = 0;
q = pixels;
+ end = pixels + bmp->width * bmp->height;
for (y = 0; y < bmp->height; )
{ count = ReadBlobByte (src);
@@ -884,7 +886,10 @@ static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int com
{ /* Encoded mode. */
byte = ReadBlobByte (src);
for (i = 0; i < count; i++)
- { if (compression == 1)
+ {
+ if (q == end)
+ return 0;
+ if (compression == 1)
{ (*(q++)) = (unsigned char) byte;
}
else
@@ -896,13 +901,15 @@ static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int com
else
{ /* Escape mode. */
count = ReadBlobByte (src);
- if (count == 0x01) return;
+ if (count == 0x01) return 1;
switch (count)
{
case 0x00:
{ /* End of line. */
x = 0;
y++;
+ if (y >= bmp->height)
+ return 0;
q = pixels + y * bmp->width;
break;
}
@@ -910,13 +917,20 @@ static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int com
{ /* Delta mode. */
x += ReadBlobByte (src);
y += ReadBlobByte (src);
+ if (y >= bmp->height)
+ return 0;
+ if (x >= bmp->width)
+ return 0;
q = pixels + y * bmp->width + x;
break;
}
default:
{ /* Absolute mode. */
for (i = 0; i < count; i++)
- { if (compression == 1)
+ {
+ if (q == end)
+ return 0;
+ if (compression == 1)
{ (*(q++)) = ReadBlobByte (src);
}
else
@@ -943,7 +957,7 @@ static void DecodeImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src,unsigned int com
byte = ReadBlobByte (src); /* end of line */
byte = ReadBlobByte (src);
- return;
+ return 1;
}
/*
@@ -1143,8 +1157,18 @@ static void ReadBMPImage (wmfAPI* API,wmfBMP* bmp,BMPSource* src)
}
}
else
- { /* Convert run-length encoded raster pixels. */
- DecodeImage (API,bmp,src,(unsigned int) bmp_info.compression,data->image);
+ {
+ if (bmp_info.bits_per_pixel == 8) /* Convert run-length encoded raster pixels. */
+ {
+ if (!DecodeImage (API,bmp,src,(unsigned int) bmp_info.compression,data->image))
+ { WMF_ERROR (API,"corrupt bmp");
+ API->err = wmf_E_BadFormat;
+ }
+ }
+ else
+ { WMF_ERROR (API,"Unexpected pixel depth");
+ API->err = wmf_E_BadFormat;
+ }
}
if (ERR (API))
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