CVE-2008-2362 - RENDER Extension memory corruption

Integer overflows can occur in the code validating the parameters for
the SProcRenderCreateLinearGradient, SProcRenderCreateRadialGradient
and SProcRenderCreateConicalGradient functions, leading to memory
corruption by swapping bytes outside of the intended request
parameters.

1 files changed, 12 insertions, 4 deletions

diff --git a/render/render.c b/render/render.c
index 74c5f6387..b53e878bd 100644
--- a/render/render.c
+++ b/render/render.c
@@ -1920,6 +1920,8 @@ static int ProcRenderCreateLinearGradient (ClientPtr client)
     LEGAL_NEW_RESOURCE(stuff->pid, client);
 
     len = (client->req_len << 2) - sizeof(xRenderCreateLinearGradientReq);
+    if (stuff->nStops > UINT32_MAX/(sizeof(xFixed) + sizeof(xRenderColor)))
+	return BadLength;
     if (len != stuff->nStops*(sizeof(xFixed) + sizeof(xRenderColor)))
         return BadLength;
 
@@ -2493,18 +2495,18 @@ SProcRenderCreateSolidFill(ClientPtr client)
     return (*ProcRenderVector[stuff->renderReqType]) (client);
 }
 
-static void swapStops(void *stuff, int n)
+static void swapStops(void *stuff, int num)
 {
-    int i;
+    int i, n;
     CARD32 *stops;
     CARD16 *colors;
     stops = (CARD32 *)(stuff);
-    for (i = 0; i < n; ++i) {
+    for (i = 0; i < num; ++i) {
         swapl(stops, n);
         ++stops;
     }
     colors = (CARD16 *)(stops);
-    for (i = 0; i < 4*n; ++i) {
+    for (i = 0; i < 4*num; ++i) {
         swaps(stops, n);
         ++stops;
     }
@@ -2527,6 +2529,8 @@ SProcRenderCreateLinearGradient (ClientPtr client)
     swapl(&stuff->nStops, n);
 
     len = (client->req_len << 2) - sizeof(xRenderCreateLinearGradientReq);
+    if (stuff->nStops > UINT32_MAX/(sizeof(xFixed) + sizeof(xRenderColor)))
+	return BadLength;
     if (len != stuff->nStops*(sizeof(xFixed) + sizeof(xRenderColor)))
         return BadLength;
 
@@ -2554,6 +2558,8 @@ SProcRenderCreateRadialGradient (ClientPtr client)
     swapl(&stuff->nStops, n);
 
     len = (client->req_len << 2) - sizeof(xRenderCreateRadialGradientReq);
+    if (stuff->nStops > UINT32_MAX/(sizeof(xFixed) + sizeof(xRenderColor)))
+	return BadLength;
     if (len != stuff->nStops*(sizeof(xFixed) + sizeof(xRenderColor)))
         return BadLength;
 
@@ -2578,6 +2584,8 @@ SProcRenderCreateConicalGradient (ClientPtr client)
     swapl(&stuff->nStops, n);
 
     len = (client->req_len << 2) - sizeof(xRenderCreateConicalGradientReq);
+    if (stuff->nStops > UINT32_MAX/(sizeof(xFixed) + sizeof(xRenderColor)))
+	return BadLength;
     if (len != stuff->nStops*(sizeof(xFixed) + sizeof(xRenderColor)))
         return BadLength;