Date: Thu, 10 Dec 2009 23:56:21 GMT From: Kevin Day <kevin@your.org> To: freebsd-gnats-submit@FreeBSD.org Subject: bin/141359: [patch] jls(8) segfault if a jail has more than 6 ipv4 addresses Message-ID: <200912102356.nBANuL2S040750@www.freebsd.org> Resent-Message-ID: <200912110000.nBB00EmJ093002@freefall.freebsd.org>
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>Number: 141359
>Category: bin
>Synopsis: [patch] jls(8) segfault if a jail has more than 6 ipv4 addresses
>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: Fri Dec 11 00:00:14 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator: Kevin Day
>Release: 8.0-RELEASE
>Organization:
Your.Org, Inc.
>Environment:
FreeBSD cs03.your.org 8.0-RELEASE-p1 FreeBSD 8.0-RELEASE-p1 #4: Thu Dec 3 19:11:35 UTC 2009 root@cs03.your.org:/usr/src/sys/amd64/compile/SERVER amd64
>Description:
If you bind more than 6 ipv4 addresses to a jail, then run jls(8), it segfaults after trying to copy the array of IPs to a single jail.
The crash appears in:
#1 0x000000080064d6c7 in jailparam_get (jp=0x800a02600, njp=5, flags=0) at /usr/src/lib/libjail/jail.c:581
(gdb) list
576 JAIL_ERRMSGLEN);
577 return (-1);
578 }
579 }
580 jiov[ai].iov_base = jp[j].jp_value;
581 memset(jiov[ai].iov_base, 0, jiov[ai].iov_len);
582 ai++;
583 } else if (jp + j != jp_key) {
584 jiov[i].iov_base = jp[j].jp_name;
585 jiov[i].iov_len = strlen(jp[j].jp_name) + 1;
It's crashing on memset, because iov_base is null:
(gdb) print jiov[ai]
$1 = {iov_base = 0x0, iov_len = 28}
(gdb) print j
$2 = 1
(gdb) print jp[j]
$3 = {jp_name = 0x800a11040 "ip4.addr", jp_value = 0x0, jp_valuelen = 28, jp_elemlen = 4, jp_ctltype = -1073479675, jp_structtype = 1, jp_flags = 16777216}
>How-To-Repeat:
>Fix:
--- /usr/src/lib/libjail/jail.c.orig 2009-12-10 23:47:06.000000000 +0000
+++ /usr/src/lib/libjail/jail.c 2009-12-10 23:47:39.000000000 +0000
@@ -564,7 +564,8 @@
if (jp[j].jp_elemlen && !(jp[j].jp_flags & JP_RAWVALUE)) {
ai++;
jiov[ai].iov_len += jp[j].jp_elemlen * ARRAY_SLOP;
- if (jp[j].jp_valuelen >= jiov[ai].iov_len)
+ if (jp[j].jp_value != NULL &&
+ jp[j].jp_valuelen >= jiov[ai].iov_len)
jiov[ai].iov_len = jp[j].jp_valuelen;
else {
jp[j].jp_valuelen = jiov[ai].iov_len;
This fixes the crash, and makes jls appear to give the full list of IPs. I'm totally lost trying to follow what this function is doing, so I don't know if this is actually fixing the real bug or just working around the problem. Someone who knows libjail better than I should probably review this.
>Release-Note:
>Audit-Trail:
>Unformatted:
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