From 8b14f7b74284900b95a319ec80c4333e63af2296 Mon Sep 17 00:00:00 2001 From: Matthieu Herrb Date: Thu, 17 Jan 2008 15:28:42 +0100 Subject: [PATCH] Fix for CVE-2007-6429 - MIT-SHM and EVI extensions integer overflows. --- Xext/EVI.c | 15 ++++++++++++++- Xext/sampleEVI.c | 29 ++++++++++++++++++++++++----- Xext/shm.c | 46 ++++++++++++++++++++++++++++++++++++++-------- 3 files changed, 76 insertions(+), 14 deletions(-) diff --git a/Xext/EVI.c b/Xext/EVI.c index 8fe3481..13bd32a 100644 --- a/Xext/EVI.c +++ b/Xext/EVI.c @@ -34,6 +34,7 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE. #include #include "EVIstruct.h" #include "modinit.h" +#include "scrnintstr.h" #if 0 static unsigned char XEVIReqCode = 0; @@ -87,10 +88,22 @@ ProcEVIGetVisualInfo(ClientPtr client) { REQUEST(xEVIGetVisualInfoReq); xEVIGetVisualInfoReply rep; - int n, n_conflict, n_info, sz_info, sz_conflict; + int i, n, n_conflict, n_info, sz_info, sz_conflict; VisualID32 *conflict; + unsigned int total_visuals = 0; xExtendedVisualInfo *eviInfo; int status; + + /* + * do this first, otherwise REQUEST_FIXED_SIZE can overflow. we assume + * here that you don't have more than 2^32 visuals over all your screens; + * this seems like a safe assumption. + */ + for (i = 0; i < screenInfo.numScreens; i++) + total_visuals += screenInfo.screens[i]->numVisuals; + if (stuff->n_visual > total_visuals) + return BadValue; + REQUEST_FIXED_SIZE(xEVIGetVisualInfoReq, stuff->n_visual * sz_VisualID32); status = eviPriv->getVisualInfo((VisualID32 *)&stuff[1], (int)stuff->n_visual, &eviInfo, &n_info, &conflict, &n_conflict); diff --git a/Xext/sampleEVI.c b/Xext/sampleEVI.c index 7508aa7..b871bfd 100644 --- a/Xext/sampleEVI.c +++ b/Xext/sampleEVI.c @@ -34,6 +34,13 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE. #include #include "EVIstruct.h" #include "scrnintstr.h" + +#if HAVE_STDINT_H +#include +#elif !defined(UINT32_MAX) +#define UINT32_MAX 0xffffffffU +#endif + static int sampleGetVisualInfo( VisualID32 *visual, int n_visual, @@ -42,24 +49,36 @@ static int sampleGetVisualInfo( VisualID32 **conflict_rn, int *n_conflict_rn) { - int max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens; + unsigned int max_sz_evi; VisualID32 *temp_conflict; xExtendedVisualInfo *evi; - int max_visuals = 0, max_sz_conflict, sz_conflict = 0; + unsigned int max_visuals = 0, max_sz_conflict, sz_conflict = 0; register int visualI, scrI, sz_evi = 0, conflictI, n_conflict; - *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi); - if (!*evi_rn) - return BadAlloc; + + if (n_visual > UINT32_MAX/(sz_xExtendedVisualInfo * screenInfo.numScreens)) + return BadAlloc; + max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens; + for (scrI = 0; scrI < screenInfo.numScreens; scrI++) { if (screenInfo.screens[scrI]->numVisuals > max_visuals) max_visuals = screenInfo.screens[scrI]->numVisuals; } + + if (n_visual > UINT32_MAX/(sz_VisualID32 * screenInfo.numScreens + * max_visuals)) + return BadAlloc; max_sz_conflict = n_visual * sz_VisualID32 * screenInfo.numScreens * max_visuals; + + *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi); + if (!*evi_rn) + return BadAlloc; + temp_conflict = (VisualID32 *)xalloc(max_sz_conflict); if (!temp_conflict) { xfree(*evi_rn); return BadAlloc; } + for (scrI = 0; scrI < screenInfo.numScreens; scrI++) { for (visualI = 0; visualI < n_visual; visualI++) { evi[sz_evi].core_visual_id = visual[visualI]; diff --git a/Xext/shm.c b/Xext/shm.c index ac587be..5633be9 100644 --- a/Xext/shm.c +++ b/Xext/shm.c @@ -711,6 +711,8 @@ ProcPanoramiXShmCreatePixmap( int i, j, result, rc; ShmDescPtr shmdesc; REQUEST(xShmCreatePixmapReq); + unsigned int width, height, depth; + unsigned long size; PanoramiXRes *newPix; REQUEST_SIZE_MATCH(xShmCreatePixmapReq); @@ -724,11 +726,26 @@ ProcPanoramiXShmCreatePixmap( return rc; VERIFY_SHMPTR(stuff->shmseg, stuff->offset, TRUE, shmdesc, client); - if (!stuff->width || !stuff->height) + + width = stuff->width; + height = stuff->height; + depth = stuff->depth; + if (!width || !height || !depth) { client->errorValue = 0; return BadValue; } + if (width > 32767 || height > 32767) + return BadAlloc; + size = PixmapBytePad(width, depth) * height; + if (sizeof(size) == 4) { + if (size < width * height) + return BadAlloc; + /* thankfully, offset is unsigned */ + if (stuff->offset + size < size) + return BadAlloc; + } + if (stuff->depth != 1) { pDepth = pDraw->pScreen->allowedDepths; @@ -739,9 +756,7 @@ ProcPanoramiXShmCreatePixmap( return BadValue; } CreatePmap: - VERIFY_SHMSIZE(shmdesc, stuff->offset, - PixmapBytePad(stuff->width, stuff->depth) * stuff->height, - client); + VERIFY_SHMSIZE(shmdesc, stuff->offset, size, client); if(!(newPix = (PanoramiXRes *) xalloc(sizeof(PanoramiXRes)))) return BadAlloc; @@ -1040,6 +1055,8 @@ ProcShmCreatePixmap(client) register int i, rc; ShmDescPtr shmdesc; REQUEST(xShmCreatePixmapReq); + unsigned int width, height, depth; + unsigned long size; REQUEST_SIZE_MATCH(xShmCreatePixmapReq); client->errorValue = stuff->pid; @@ -1052,11 +1069,26 @@ ProcShmCreatePixmap(client) return rc; VERIFY_SHMPTR(stuff->shmseg, stuff->offset, TRUE, shmdesc, client); - if (!stuff->width || !stuff->height) + + width = stuff->width; + height = stuff->height; + depth = stuff->depth; + if (!width || !height || !depth) { client->errorValue = 0; return BadValue; } + if (width > 32767 || height > 32767) + return BadAlloc; + size = PixmapBytePad(width, depth) * height; + if (sizeof(size) == 4) { + if (size < width * height) + return BadAlloc; + /* thankfully, offset is unsigned */ + if (stuff->offset + size < size) + return BadAlloc; + } + if (stuff->depth != 1) { pDepth = pDraw->pScreen->allowedDepths; @@ -1067,9 +1099,7 @@ ProcShmCreatePixmap(client) return BadValue; } CreatePmap: - VERIFY_SHMSIZE(shmdesc, stuff->offset, - PixmapBytePad(stuff->width, stuff->depth) * stuff->height, - client); + VERIFY_SHMSIZE(shmdesc, stuff->offset, size, client); pMap = (*shmFuncs[pDraw->pScreen->myNum]->CreatePixmap)( pDraw->pScreen, stuff->width, stuff->height, stuff->depth, -- 1.5.3.5