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fixed possible paramblock memory overwrite in DOS_Execute

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@299
This commit is contained in:
Ulf Wohlers 2002-09-21 11:08:03 +00:00
parent b778104885
commit 52f4e4a2fb
1 changed files with 12 additions and 7 deletions
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19
src/dos/dos_execute.cpp
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@ -198,7 +198,7 @@ static void SetupCMDLine(Bit16u pspseg,ParamBlock * block)
psp.SetCommandTail(block->exec.cmdtail);
}
bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
bool DOS_Execute(char * name,ParamBlock * _block,Bit8u flags) {
EXE_Header head;Bitu i;
Bit16u fhandle;Bit16u len;Bit32u pos;
Bit16u pspseg,envseg,loadseg,memsize,readsize;
@ -208,6 +208,11 @@ bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
if (flags!=LOADNGO && flags!=OVERLAY) {
E_Exit("DOS:Not supported execute mode %d for file %s",flags,name);
}
// Parameter block may be overwritten on load, so save these values !
ParamBlock block;
memcpy(&block,_block,sizeof(ParamBlock));
/* Check for EXE or COM File */
bool iscom=false;
if (!DOS_OpenFile(name,OPEN_READ,&fhandle)) return false;
@ -224,7 +229,7 @@ bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
}
if (flags!=OVERLAY) {
/* Create an environment block */
envseg=block->exec.envseg;
envseg=block.exec.envseg;
if (!MakeEnv(name,&envseg)) {
DOS_CloseFile(fhandle);
return false;
@ -249,8 +254,8 @@ bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
loadseg=pspseg+16;
/* Setup a psp */
SetupPSP(pspseg,memsize,envseg);
SetupCMDLine(pspseg,block);
} else loadseg=block->overlay.loadseg,0;
SetupCMDLine(pspseg,&block);
} else loadseg=block.overlay.loadseg,0;
/* Load the executable */
loadaddress=HostMake(loadseg,0);
if (iscom) { /* COM Load 64k - 256 bytes max */
@ -270,7 +275,7 @@ bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
}
/* Relocate the exe image */
Bit16u relocate;
if (flags==OVERLAY) relocate=block->overlay.relocation;
if (flags==OVERLAY) relocate=block.overlay.relocation;
else relocate=loadseg;
pos=head.reloctable;DOS_SeekFile(fhandle,&pos,0);
for (i=0;i<head.relocations;i++) {
@ -306,8 +311,8 @@ bool DOS_Execute(char * name,ParamBlock * block,Bit8u flags) {
/* save vectors */
newpsp.SaveVectors();
/* copy fcbs */
newpsp.SetFCB1(block->exec.fcb1);
newpsp.SetFCB2(block->exec.fcb2);
newpsp.SetFCB1(block.exec.fcb1);
newpsp.SetFCB2(block.exec.fcb2);
/* Set the stack for new program */
SegSet16(ss,RealSeg(sssp));reg_sp=RealOff(sssp);
/* Add some flags and CS:IP on the stack for the IRET */