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prevent execution of zero-byte files

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2248
This commit is contained in:
Sebastian Strohhäcker 2005-07-22 10:03:20 +00:00
parent d4cf66ccae
commit cb8b2b2c58
1 changed files with 31 additions and 19 deletions
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50
src/dos/dos_execute.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: dos_execute.cpp,v 1.47 2005-07-12 18:59:31 qbix79 Exp $ */
/* $Id: dos_execute.cpp,v 1.48 2005-07-22 10:03:20 c2woody Exp $ */
#include <string.h>
#include <ctype.h>
@ -243,21 +243,31 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
DOS_CloseFile(fhandle);
return false;
}
/* Convert the header to correct endian, i hope this works */
HostPt endian=(HostPt)&head;
for (i=0;i<sizeof(EXE_Header)/2;i++) {
*((Bit16u *)endian)=host_readw(endian);
endian+=2;
}
if (len<sizeof(EXE_Header)) iscom=true;
if ((head.signature!=MAGIC1) && (head.signature!=MAGIC2)) iscom=true;
else {
if(head.pages & ~0x07ff) /* 1 MB dos maximum address limit. Fixes TC3 IDE (kippesoep) */
LOG(LOG_EXEC,LOG_NORMAL)("Weird header: head.pages > 1 MB");
head.pages&=0x07ff;
headersize = head.headersize*16;
imagesize = head.pages*512-headersize;
if (imagesize+headersize<512) imagesize = 512-headersize;
if (len<sizeof(EXE_Header)) {
if (len==0) {
/* Prevent executing zero byte files */
DOS_SetError(DOSERR_ACCESS_DENIED);
DOS_CloseFile(fhandle);
return false;
}
/* Otherwise must be a .com file */
iscom=true;
} else {
/* Convert the header to correct endian, i hope this works */
HostPt endian=(HostPt)&head;
for (i=0;i<sizeof(EXE_Header)/2;i++) {
*((Bit16u *)endian)=host_readw(endian);
endian+=2;
}
if ((head.signature!=MAGIC1) && (head.signature!=MAGIC2)) iscom=true;
else {
if(head.pages & ~0x07ff) /* 1 MB dos maximum address limit. Fixes TC3 IDE (kippesoep) */
LOG(LOG_EXEC,LOG_NORMAL)("Weird header: head.pages > 1 MB");
head.pages&=0x07ff;
headersize = head.headersize*16;
imagesize = head.pages*512-headersize;
if (imagesize+headersize<512) imagesize = 512-headersize;
}
}
if (flags!=OVERLAY) {
/* Create an environment block */
@ -284,9 +294,11 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
else memsize=maxsize;
if (!DOS_AllocateMemory(&pspseg,&memsize)) E_Exit("DOS:Exec error in memory");
loadseg=pspseg+16;
if ((!iscom) & (head.minmemory == 0) & (head.maxmemory == 0))
loadseg = (0x9e000 - imagesize)/16; //c2woody
if (!iscom) {
/* Check if requested to load program into upper part of allocated memory */
if ((head.minmemory == 0) && (head.maxmemory == 0))
loadseg = ((pspseg+memsize)*0x10-imagesize)/0x10;
}
} else loadseg=block.overlay.loadseg;
/* Load the executable */
Bit8u * loadbuf=(Bit8u *)new Bit8u[0x10000];