Date: Mon, 17 Sep 2001 16:01:03 -0500 From: Alfred Perlstein <bright@mu.org> To: Matt Dillon <dillon@earth.backplane.com> Cc: hackers@FreeBSD.org Subject: Re: bug in sshd - signal during free() Message-ID: <20010917160103.Z968@elvis.mu.org> In-Reply-To: <200109172032.f8HKW6M41638@earth.backplane.com>; from dillon@earth.backplane.com on Mon, Sep 17, 2001 at 01:32:06PM -0700 References: <200109172032.f8HKW6M41638@earth.backplane.com>
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* Matt Dillon <dillon@earth.backplane.com> [010917 15:32] wrote: > sshd died on one of our machines today. The traceback seems to > indicate that a signal is interrupting a free(). I'm going to > play with the code a bit to see if there's an easy fix. > > This bug can't occur very often... the key regeneration signal > has to occur *just* as sshd is trying to free() something. The bug seems more likely to be caused by use of unsafe functions in a signal handler. I'm really suprised that the OpenSSH team didn't slap whomever decided to do so much processing within a signal handler silly. > > -Matt > > (gdb) back > #0 0x28231e34 in kill () from /usr/lib/libc.so.4 > #1 0x2826dd8a in abort () from /usr/lib/libc.so.4 > #2 0x2826c899 in isatty () from /usr/lib/libc.so.4 > #3 0x2826c8cf in isatty () from /usr/lib/libc.so.4 > #4 0x2826d907 in malloc () from /usr/lib/libc.so.4 > #5 0x2826be58 in __smakebuf () from /usr/lib/libc.so.4 > #6 0x2826bdec in __swsetup () from /usr/lib/libc.so.4 > #7 0x282663ef in vfprintf () from /usr/lib/libc.so.4 > #8 0x28266059 in fprintf () from /usr/lib/libc.so.4 > #9 0x2824e0ed in vsyslog () from /usr/lib/libc.so.4 > #10 0x2824e009 in syslog () from /usr/lib/libc.so.4 > #11 0x804feb3 in do_log () > #12 0x806ade3 in log () > #13 0x804c742 in key_regeneration_alarm () > #14 0xbfbfffac in ?? () > #15 0x2826da35 in free () from /usr/lib/libc.so.4 > #16 0x805f087 in xfree () > #17 0x804d8be in main () > #18 0x804c50d in _start () > (gdb) -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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