diff -urN zgv-5.8/ChangeLog zgv/ChangeLog --- zgv-5.8/ChangeLog Mon Mar 29 05:34:03 2004 +++ zgv/ChangeLog Sun Oct 31 15:23:27 2004 @@ -1,3 +1,27 @@ +2004-10-31 Russell Marks <russell.marks@ntlworld.com> + + * Added width/height limits to all picture readers, 32767x32767 is + now the maximum image size supported (consistent with xzgv). This + is a crude (albeit effective) fix for heap overflow bugs - there + may yet be more subtle problems, but I can't really fix them until + I know they're there. :-) Thanks to Luke Macken for letting me + know about the heap overflow problems. I suppose I should also + thank "infamous41md" for publishing the original exploit (for the + XPM colours bug), even if he didn't bother emailing me or + anything. + + * src/readxpm.c (read_xpm_file): fix for exploitable malloc() arg + overflow. There are several more of these in zgv, but this is the + easiest to fix. + +2004-07-08 Russell Marks <russell.marks@ntlworld.com> + + * src/readgif.c (read_gif_file): added more multiple-image (e.g. + animated) GIF brokenness checks than before. Previously it was + possible to get a segfault with the `right' file, despite there + already being various range checks. Thanks to Mikulas Patocka for + spotting this. + 2004-03-29 Russell Marks <russell.marks@ntlworld.com> * Version 5.8. diff -urN zgv-5.8/src/readbmp.c zgv/src/readbmp.c --- zgv-5.8/src/readbmp.c Thu Oct 4 16:48:36 2001 +++ zgv/src/readbmp.c Sun Oct 31 14:32:44 2004 @@ -177,7 +177,8 @@ bytepp=1; if ((pp->bpp == 24) && (*output_type == 3)) bytepp = 3; - if ((work_bmap = *bmap = calloc (w * (h + 2) * bytepp,1)) == NULL) + if (WH_BAD(w,h) || + (work_bmap = *bmap = calloc (w * (h + 2) * bytepp,1)) == NULL) CLOSE_AND_RET(_PICERR_NOMEM); bytes_in_image=w*h*bytepp; diff -urN zgv-5.8/src/readgif.c zgv/src/readgif.c --- zgv-5.8/src/readgif.c Sat Mar 15 02:39:42 2003 +++ zgv/src/readgif.c Sun Oct 31 14:31:48 2004 @@ -491,7 +491,7 @@ readcolmap(in,im->cmap,lnumcols); } - if((im->image=(byte *)malloc(width*height))==NULL) + if(WH_BAD(width,height) || (im->image=(byte *)malloc(width*height))==NULL) { fclose(in); return(_PICERR_NOMEM); @@ -599,7 +599,8 @@ /* allocate main image and palette */ -if((*theimageptr=(byte *)malloc(ginfo->width*ginfo->height))==NULL) +if(WH_BAD(ginfo->width,ginfo->height) || + (*theimageptr=(byte *)malloc(ginfo->width*ginfo->height))==NULL) { images_cleanup(); return(_PICERR_NOMEM); @@ -668,7 +669,11 @@ for(i=0;i<imagecount;i++) { int x,y,left,w; - unsigned char *ptr1,*ptr2; + unsigned char *ptr1,*ptr2,*oldptr1; + + /* basic width/height vs. "screen" checks, left/top handled elsewhere */ + if(images[i]->width>swidth) images[i]->width=swidth; + if(images[i]->height>sheight) images[i]->height=sheight; /* for images after the first, we need to set the initial contents * (as far as GIF is concerned, the `screen' contents) as directed @@ -708,20 +713,28 @@ */ } } - - ptr1=ptr+images[i]->left+images[i]->top*swidth; - ptr2=images[i]->image; - - for(y=0;y<images[i]->height;y++) + + /* an image with left or top offscreen is broken, but relying + * unknowingly on the image not appearing at all. So skip it. + */ + if(images[i]->left<swidth && images[i]->top<sheight) { - for(x=0;x<images[i]->width;x++) - if(!(images[i]->gcb_control&1) || /* if no transparent col defined */ - images[i]->transparent_col!=*ptr2) - *ptr1++=*ptr2++; - else - ptr1++,ptr2++; + ptr1=ptr+images[i]->left+images[i]->top*swidth; - ptr1+=swidth-images[i]->width; + for(y=0;y<images[i]->height && images[i]->top+y<sheight;y++) + { + oldptr1=ptr1; + ptr2=images[i]->image+y*images[i]->width; + + for(x=0;x<images[i]->width && images[i]->left+x<swidth;x++) + if(!(images[i]->gcb_control&1) || /* if no transparent col defined */ + images[i]->transparent_col!=*ptr2) + *ptr1++=*ptr2++; + else + ptr1++,ptr2++; + + ptr1=oldptr1+swidth; + } } ptr+=swidth*sheight; diff -urN zgv-5.8/src/readjpeg.c zgv/src/readjpeg.c --- zgv-5.8/src/readjpeg.c Wed Sep 27 17:28:30 2000 +++ zgv/src/readjpeg.c Sun Oct 31 14:54:26 2004 @@ -190,10 +190,10 @@ height=cinfo.output_height; } -theimage=(byte *)malloc(pixelsize*width*height); -if(theimage==NULL) +if(WH_BAD(width,height) || + (theimage=(byte *)malloc(pixelsize*width*height))==NULL) { - jpegerr("Out of memory"); + jpegerr("Out of memory"); /* XXX misleading if width/height are bad */ longjmp(jerr.setjmp_buffer,1); } diff -urN zgv-5.8/src/readmrf.c zgv/src/readmrf.c --- zgv-5.8/src/readmrf.c Wed Oct 21 07:28:23 1998 +++ zgv/src/readmrf.c Sun Oct 31 14:56:33 2004 @@ -103,7 +103,8 @@ w64=(w+63)/64; h64=(h+63)/64; -if((*bmap=malloc(w*h))==NULL || +if(WH_BAD(w64*64,h64*64) || WH_BAD(w,h) || + (*bmap=malloc(w*h))==NULL || (image=calloc(w64*h64*64*64,1))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); diff -urN zgv-5.8/src/readpcd.c zgv/src/readpcd.c --- zgv-5.8/src/readpcd.c Thu Sep 30 01:56:59 1999 +++ zgv/src/readpcd.c Sun Oct 31 14:57:37 2004 @@ -39,7 +39,7 @@ if((*output_type)!=1)*output_type=3; -if((*bmap=malloc(w*(h+3-*output_type)*(*output_type)))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*(h+3-*output_type)*(*output_type)))==NULL) return(_PICERR_NOMEM); if((*pal=malloc(768))==NULL) diff -urN zgv-5.8/src/readpcx.c zgv/src/readpcx.c --- zgv-5.8/src/readpcx.c Wed Mar 31 00:11:36 1999 +++ zgv/src/readpcx.c Sun Oct 31 14:59:30 2004 @@ -127,7 +127,7 @@ bytemax=(1<<30); /* we use a 'y<h' test instead for these files */ /* the normal +2 lines in case we're dithering a 24-bit file */ -if((*bmap=malloc(w*(h+2)*bytepp))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*(h+2)*bytepp))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); /* need this if more than one bitplane */ diff -urN zgv-5.8/src/readpng.c zgv/src/readpng.c --- zgv-5.8/src/readpng.c Mon Jul 7 19:59:18 2003 +++ zgv/src/readpng.c Sun Oct 31 15:00:23 2004 @@ -223,8 +223,9 @@ /* allocate image memory (with two extra lines for dithering) */ -theimage=(byte *)malloc(pixelsize*width*(height+2)); -if(theimage==NULL) return(_PICERR_NOMEM); +if(WH_BAD(width,height) || + (theimage=(byte *)malloc(pixelsize*width*(height+2)))==NULL) + return(_PICERR_NOMEM); ilheight=height*number_passes; diff -urN zgv-5.8/src/readpnm.c zgv/src/readpnm.c --- zgv-5.8/src/readpnm.c Thu Jun 1 15:45:53 2000 +++ zgv/src/readpnm.c Sun Oct 31 15:02:58 2004 @@ -144,7 +144,7 @@ * 3 times as much for each line, which works out only meaning * 3x as much for the last line. If you see what I mean. (!?) */ -if((*bmap=malloc(w*(h+2)*bytepp))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*(h+2)*bytepp))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); @@ -294,6 +294,8 @@ int ditherinit(int w) { +if(WH_BAD(w+10,sizeof(int))) return(0); + ditherfinish(); /* make sure any previous mem is unallocated */ if((evenerr=calloc(3*(w+10),sizeof(int)))==NULL || (odderr =calloc(3*(w+10),sizeof(int)))==NULL || @@ -418,7 +420,7 @@ if((maxval=read_next_number(in))!=255) return(_PICERR_CORRUPT); -if((*bmap=malloc(w*h))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*h))==NULL) return(_PICERR_NOMEM); count=fread(*bmap,1,w*h,in); diff -urN zgv-5.8/src/readprf.c zgv/src/readprf.c --- zgv-5.8/src/readprf.c Mon Jan 15 20:31:51 2001 +++ zgv/src/readprf.c Sun Oct 31 15:05:24 2004 @@ -184,7 +184,7 @@ } n=width*squaresize; -if((planebuf[0]=work_planebuf=calloc(n,planes))==NULL) +if(WH_BAD(width,height) || (planebuf[0]=work_planebuf=calloc(n,planes))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); for(f=1;f<planes;f++) planebuf[f]=planebuf[f-1]+n; @@ -202,7 +202,9 @@ } /* add the usual extra 2 lines in case of dithering */ -if((*bmap=work_bmap=malloc(width*(height+2)*planes))==NULL) +/* width/height check already done, but WTF :-) */ +if(WH_BAD(width,height) || + (*bmap=work_bmap=malloc(width*(height+2)*planes))==NULL) { free(planebuf[0]); CLOSE_AND_RET(_PICERR_NOMEM); diff -urN zgv-5.8/src/readtga.c zgv/src/readtga.c --- zgv-5.8/src/readtga.c Wed Oct 24 17:02:24 2001 +++ zgv/src/readtga.c Sun Oct 31 15:05:54 2004 @@ -179,7 +179,7 @@ * 3 times as much for each line, which works out only meaning * 3x as much for the last line. If you see what I mean. (!?) */ -if((*bmap=malloc(w*(h+2)*bytepp))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*(h+2)*bytepp))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); diff -urN zgv-5.8/src/readtiff.c zgv/src/readtiff.c --- zgv-5.8/src/readtiff.c Thu Jan 18 23:45:59 2001 +++ zgv/src/readtiff.c Sun Oct 31 15:06:15 2004 @@ -86,7 +86,8 @@ * certain the dithering has room. */ numpix=width*height; -if((image=*bmap=work_bmap=malloc(numpix*sizeof(uint32)+width*3*2))==NULL) +if(WH_BAD(width,height) || + (image=*bmap=work_bmap=malloc(numpix*sizeof(uint32)+width*3*2))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); /* XXX what about hffunc!? */ diff -urN zgv-5.8/src/readxbm.c zgv/src/readxbm.c --- zgv-5.8/src/readxbm.c Wed Oct 21 07:28:23 1998 +++ zgv/src/readxbm.c Sun Oct 31 15:08:14 2004 @@ -97,7 +97,7 @@ w8=(w+7)/8; -if((*bmap=image=malloc(w*h))==NULL) +if(WH_BAD(w,h) || (*bmap=image=malloc(w*h))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); /* save stuff in case of abort */ diff -urN zgv-5.8/src/readxpm.c zgv/src/readxpm.c --- zgv-5.8/src/readxpm.c Sat Jan 22 11:32:28 2000 +++ zgv/src/readxpm.c Sun Oct 31 15:08:48 2004 @@ -180,7 +180,7 @@ if(colchars!=NULL) free(colchars); /* alloc colchars array */ -if((colchars=malloc(ncols*sizeof(struct colchars_tag)))==NULL) +if(ncols>(1<<24) || (colchars=malloc(ncols*sizeof(struct colchars_tag)))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); @@ -369,7 +369,7 @@ */ /* extra lines are in case we're dithering. */ -if((*bmap=malloc(w*(h+2)*bytepp))==NULL) +if(WH_BAD(w,h) || (*bmap=malloc(w*(h+2)*bytepp))==NULL) CLOSE_AND_RET(_PICERR_NOMEM); ptr=*bmap; diff -urN zgv-5.8/src/zgv.h zgv/src/zgv.h --- zgv-5.8/src/zgv.h Sat Feb 21 16:31:29 2004 +++ zgv/src/zgv.h Sun Oct 31 14:58:34 2004 @@ -66,3 +66,12 @@ /* make 15/16-bit colours, used in a few different places */ #define GET15BITCOLOUR(r,g,b) ((((r)&0xf8)<<7)|(((g)&0xf8)<<2)|((b)>>3)) #define GET16BITCOLOUR(r,g,b) ((((r)&0xf8)<<8)|(((g)&0xfc)<<3)|((b)>>3)) + +/* range check on width and height as a crude way of avoiding overflows + * when calling malloc/calloc. The maximum we can allow is around 37000, + * but 32767 at least makes it consistent with xzgv. :-) + * Adds an extra 2 to height for max-height check, as we usually allocate + * 2 more lines to allow for dithering. + */ +#define WH_MAX 32767 +#define WH_BAD(w,h) ((w)<=0 || (w)>WH_MAX || (h)<=0 || ((h)+2)>WH_MAX)