From a13bb127d28440848246009b673382562f87ccb6 Mon Sep 17 00:00:00 2001 From: Bill Paul Date: Sat, 8 Jun 1996 04:52:57 +0000 Subject: Aw c'mon. I'm being driven mad by plenty of other things. I don't need this. Consider the following code: case 'O': output_filename = malloc(strlen(arg)+4); strcpy(output_filename, arg); strcat(output_filename, ".tmp"); real_output_filename = arg; return; The idea here is to malloc() a buffer big enough to hold the name of a supplied file name, plus ".tmp". So we malloc() 'size of filename' bytes plus 4, right? Wrong! ".tmp" is _FIVE_ bytes long! There's a traling '\0' which strcat() gleefully tacks on _outside_ the bounds of the buffer. Result: program corrupts own memory. Program SEGVs at seemingly random times. Bill not like random SEGVs. Bill smash. Know how I found this? I've been trying to bootstrap -current on my 2.1.0-RELEASE machine at work and I couldn't seem to get libc.a built because the linker would intermittently blow chunks while executing things like 'ld -O foo.o -X -r foo.o'. Since this is an initial bootstrap version of ld, it was linked against the 2.1.0 libc, who's malloc() behaves differently than that in -current. Presumeably ld -O doesn't blow up in -current, otherwise someone would have spotted this already. I don't know if this is a bug or a feature. Anyway. I'm changing the strlen(arg)+4 to strlen(arg)+5. Bah. --- gnu/usr.bin/ld/ld.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'gnu') diff --git a/gnu/usr.bin/ld/ld.c b/gnu/usr.bin/ld/ld.c index a0d8ee1d7ef4..a1205fd968f4 100644 --- a/gnu/usr.bin/ld/ld.c +++ b/gnu/usr.bin/ld/ld.c @@ -32,7 +32,7 @@ static char sccsid[] = "@(#)ld.c 6.10 (Berkeley) 5/22/91"; Set, indirect, and warning symbol features added by Randy Smith. */ /* - * $Id: ld.c,v 1.32 1996/04/24 23:31:08 jdp Exp $ + * $Id: ld.c,v 1.33 1996/05/28 16:17:48 phk Exp $ */ /* Define how to initialize system-dependent header fields. */ @@ -700,7 +700,7 @@ decode_option(swt, arg) return; case 'O': - output_filename = malloc(strlen(arg)+4); + output_filename = malloc(strlen(arg)+5); strcpy(output_filename, arg); strcat(output_filename, ".tmp"); real_output_filename = arg; -- cgit v1.2.3