Date: Wed, 1 Feb 2012 10:26:40 +0400 (MSK) From: Yuri Pankov <yuri.pankov@gmail.com> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/164684: [kern][patch] Zero out dynamically allocated sbufs Message-ID: <201202010626.q116QePw067371@sirius.xvoid.org> Resent-Message-ID: <201202010630.q116UEm5043386@freefall.freebsd.org>
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>Number: 164684
>Category: kern
>Synopsis: [kern][patch] Zero out dynamically allocated sbufs
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Feb 01 06:30:14 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: Yuri Pankov
>Release: FreeBSD 10.0-CURRENT amd64
>Organization:
>Environment:
System: FreeBSD sirius.xvoid.org 10.0-CURRENT FreeBSD 10.0-CURRENT #1 r230537: Wed Jan 25 16:28:58 MSK 2012 yuri@sirius.xvoid.org:/usr/obj/data/src/freebsd/head/sys/GENERIC amd64
>Description:
Filing this against kernel (as the source is in sys/kern), but got the problem itself using libsbuf - sbuf_newbuf() and sbuf_extend() don't zero out the malloc'ed memory, leading to issues when malloc debugging is enabled.
>How-To-Repeat:
#include <sys/types.h>
#include <sys/sbuf.h>
#include <stdio.h>
int
main(void)
{
struct sbuf *sb = sbuf_new_auto();
sbuf_cat(sb, "TEST TEST");
printf("s_buf=%s\n", sbuf_data(sb));
return(0);
}
$ MALLOC_OPTIONS=J ./sbuf
s_buf=TEST TEST▒▒▒▒▒▒▒
$ MALLOC_OPTIONS=j ./sbuf
s_buf=TEST TEST
>Fix:
--- sbuf-dynamic.diff begins here ---
Index: sys/kern/subr_sbuf.c
===================================================================
--- sys/kern/subr_sbuf.c (revision 230853)
+++ sys/kern/subr_sbuf.c (working copy)
@@ -159,6 +159,7 @@
newbuf = SBMALLOC(newsize);
if (newbuf == NULL)
return (-1);
+ memset(newbuf, 0, newsize);
memcpy(newbuf, s->s_buf, s->s_size);
if (SBUF_ISDYNAMIC(s))
SBFREE(s->s_buf);
@@ -197,6 +198,7 @@
s->s_buf = SBMALLOC(s->s_size);
if (s->s_buf == NULL)
return (NULL);
+ memset(s->s_buf, 0, s->s_size);
SBUF_SETFLAG(s, SBUF_DYNAMIC);
return (s);
}
--- sbuf-dynamic.diff ends here ---
>Release-Note:
>Audit-Trail:
>Unformatted:
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