lwall@sdcrdcf.UUCP (Larry Wall) (06/05/87)
System: patch version 2.0
Patch #: 9
Priority: LOW
Subject: Reversed new-style context diff can cause double free().
From: lwall@sdcrdcf.UUCP
Description:
A new-style context diff that is reversed (-R) and that contains
a hunk with an assumed old or new half is not freed properly.
When there is a hunk-half assumed, the lines are duplicated
internally by copying the pointers of the actual lines from the
other half. A pair of variables then tell the freeing routine
not to free that range of fake lines since they will be freed when
the other half hunk is freed.
The problem is that the routine that swaps halves of the hunk didn't
update the variables to point to where the fake lines were moved to.
Fix: From rn, say "| patch -d DIR", where DIR is your patch source
directory. Outside of rn, say "cd DIR; patch <thisarticle".
If you don't have the patch program, apply the following by hand,
or get patch.
If patch indicates that patchlevel is the wrong version, you may need
to apply one or more previous patches, or the patch may already
have been applied. See the patchlevel.h file to find out what has or
has not been applied. In any event, don't continue with the patch.
If you are missing previous patches they can be obtained from me:
Larry Wall
{allegra,burdvax,cbosgd,ihnp4,sdcsvax}!sdcrdcf!lwall
If you send a mail message of the following form it will greatly speed
processing:
Subject: Command
@SH mailpatch PATH patch 2.0 LIST
^ note the c
where PATH is a return path FROM ME TO YOU in bang notation, and LIST
is the number of one or more patches you need, separated by spaces,
commas, and/or hyphens. Saying 35- says everything from 35 to the end.
Index: patchlevel.h
Prereq: 8
1c1
< #define PATCHLEVEL 8
---
> #define PATCHLEVEL 9
Index: pch.c
Prereq: 2.0.1.5
*** pch.c.old Thu Jun 4 16:20:28 1987
*** pch.c Thu Jun 4 16:20:43 1987
***************
*** 1,6 ****
! /* $Header: pch.c,v 2.0.1.5 87/01/30 22:47:42 lwall Exp $
*
* $Log: pch.c,v $
* Revision 2.0.1.5 87/01/30 22:47:42 lwall
* Improved responses to mangled patches.
*
--- 1,9 ----
! /* $Header: pch.c,v 2.0.1.6 87/06/04 16:18:13 lwall Exp $
*
* $Log: pch.c,v $
+ * Revision 2.0.1.6 87/06/04 16:18:13 lwall
+ * pch_swap didn't swap p_bfake and p_efake.
+ *
* Revision 2.0.1.5 87/01/30 22:47:42 lwall
* Improved responses to mangled patches.
*
***************
*** 900,905 ****
--- 903,915 ----
if (tp_char[i] == '\n') { /* account for possible blank line */
blankline = TRUE;
i++;
+ }
+ if (p_efake >= 0) { /* fix non-freeable ptr range */
+ n = p_end - i + 1;
+ if (p_efake > i)
+ n = -n;
+ p_efake += n;
+ p_bfake += n;
}
for (n=0; i <= p_end; i++,n++) {
p_line[n] = tp_line[i];