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* Check buffer overflow when reading

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git-svn-id: trunk@49012 -
This commit is contained in:
michael 2021-03-19 14:25:21 +00:00
parent 28e359f091
commit 2a96ad2715
1 changed files with 8 additions and 6 deletions
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14
rtl/unix/timezone.inc
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@ -278,6 +278,7 @@ var
buf : array[0..bufsize-1] of byte; buf : array[0..bufsize-1] of byte;
bufptr : pbyte; bufptr : pbyte;
bufbytes : tsSize; bufbytes : tsSize;
bufoverflow : boolean;
f : longint; f : longint;
tzhead : ttzhead; tzhead : ttzhead;
@ -288,22 +289,22 @@ var
readfilebuf:=bufbytes; readfilebuf:=bufbytes;
end; end;
Procedure checkbufptr; Procedure checkbufptr(asize : integer);
var var
a : tssize; a : tssize;
begin begin
a:=bufptr-@buf; a:=bufptr-@buf+asize;
if (a>bufbytes) then if (a>bufbytes) then
Writeln('Reading past end of file : ',a); bufoverflow:=true;
end; end;
function readbufbyte: byte; function readbufbyte: byte;
begin begin
// checkbufptr;
if bufptr > @buf[bufsize-1] then if bufptr > @buf[bufsize-1] then
readfilebuf; readfilebuf;
checkbufptr(1);
readbufbyte := bufptr^; readbufbyte := bufptr^;
inc(bufptr); inc(bufptr);
end; end;
@ -319,13 +320,13 @@ var
numbytes := count; numbytes := count;
if numbytes > 0 then if numbytes > 0 then
begin begin
checkbufptr(numbytes);
if assigned(dest) then if assigned(dest) then
move(bufptr^, dest^, numbytes); move(bufptr^, dest^, numbytes);
inc(bufptr, numbytes); inc(bufptr, numbytes);
dec(count, numbytes); dec(count, numbytes);
inc(readbuf, numbytes); inc(readbuf, numbytes);
inc(dest, numbytes); inc(dest, numbytes);
// checkbufptr;
end; end;
if count > 0 then if count > 0 then
readfilebuf readfilebuf
@ -462,10 +463,11 @@ begin
f:=fpopen(fn,Open_RdOnly); f:=fpopen(fn,Open_RdOnly);
if f<0 then if f<0 then
exit(False); exit(False);
bufoverflow:=false;
bufptr := @buf[bufsize-1]+1; bufptr := @buf[bufsize-1]+1;
tzhead:=default(ttzhead); tzhead:=default(ttzhead);
LockTZInfo; LockTZInfo;
ReadTimezoneFile:=(readheader() and readdata()); ReadTimezoneFile:=(readheader() and readdata()) and not BufOverflow;
ClearCurrentTZinfo; ClearCurrentTZinfo;
UnlockTZInfo; UnlockTZInfo;
fpclose(f); fpclose(f);