Re: distcheck fails test 056

[Eric Blake]

> Ralf Wildenhues <Ralf.Wildenhues <at> gmx.de> writes:

Hi Ralf, and thanks for spotting this (the bug is highly dependent on what is 
already on the heap, but I haven't been able to get valgrind to run on cygwin).

> ==8387== Conditional jump or move depends on uninitialised value(s)
> ==8387==    at 0x41F811: quotearg_buffer_restyled (quotearg.c:296)
> ==8387==    by 0x41FD0F: quotearg_n_options (quotearg.c:723)
> ==8387==    by 0x41FDF6: quotearg_n (quotearg.c:743)
> ==8387==    by 0x41FE3C: quotearg (quotearg.c:755)
> ==8387==    by 0x4027CF: m4_verror_at_line (m4.c:121)

Sure enough, I forgot to terminate the array.  Not a problem on the argv_ref 
branch (but only because I switched to length-based processing instead of NUL-
termination-based).  Committing this to branch and head.

From: Eric Blake <address@hidden>
Date: Wed, 20 Feb 2008 17:02:06 -0700
Subject: [PATCH] Fix out-of-bounds read for sanitized macro names, from 2008-02-
06.

* src/m4.c (m4_verror_at_line): Properly terminate the string.
Reported by Ralf Wildenhues.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog |    6 ++++++
 src/m4.c  |    1 +
 2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 62b78a9..0f4e496 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-02-21  Eric Blake  <address@hidden>
+
+       Fix out-of-bounds read for sanitized macro names, from 2008-02-06.
+       * src/m4.c (m4_verror_at_line): Properly terminate the string.
+       Reported by Ralf Wildenhues.
+
 2008-02-19  Eric Blake  <address@hidden>
 
        Clean up foreach example.
diff --git a/src/m4.c b/src/m4.c
index a6bc92a..af4991f 100644
--- a/src/m4.c
+++ b/src/m4.c
@@ -113,6 +113,7 @@ m4_verror_at_line (bool warn, int status, int errnum, const 
char *file,
          *p++ = *macro++;
        }
       while (*macro);
+      *p = '\0';
     }
   /* Prepend warning and the macro name, as needed.  But if that fails
      for non-memory reasons (unlikely), then still use the original
-- 
1.5.4