Date: Mon, 18 Feb 2008 15:53:09 -0500 From: Mike Tancsa <mike@sentex.net> To: Jim Bryant <freebsd@electron-tube.net> Cc: freebsd-security@freebsd.org Subject: Re: How to take down a system to the point of requiring a newfs with one line of C (userland) Message-ID: <200802182052.m1IKqkFF004605@lava.sentex.ca> In-Reply-To: <47B90868.7000900@electron-tube.net> References: <47B90868.7000900@electron-tube.net>
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At 11:24 PM 2/17/2008, Jim Bryant wrote:
>One line summary:
> Too many files in a top-level UFS-2 filesystem directory will
> cause a panic on mount.
>How to repeat the problem:
> Compile and run the following as instructed:
>
>umount that filesystem.
Hi,
I tried this on RELENG_7 and RELENG_6 and was not able to panic the box
0[releng7]# ls -l | wc
20098 200972 1377211
0[releng7]# df -i
Filesystem 1K-blocks Used Avail Capacity iused ifree
%iused Mounted on
/dev/ad6s1a 1012974 284464 647474 31% 3308 138002 2% /
devfs 1 1 0 100% 0 0 100% /dev
/dev/ad6s1d 5077038 1221890 3448986 26% 20243 639211 3% /tmp
/dev/ad6s1e 25385516 15683412 7671264 67% 370099 2927179 11% /usr
/dev/ad6s1f 40139596 847342 36081088 2% 1001 5203989 0% /var
0[releng7]#
and releng_6
0[nanobsd]# ./a.out /tmp/k
0[nanobsd]# ./a.out /tmp/kl
0[nanobsd]# ls -l /tmp/ | wc
20248 182229 1327842
0[nanobsd]# df -i
Filesystem 1K-blocks Used Avail Capacity iused ifree
%iused Mounted on
/dev/twed0s1a 1012974 109076 822862 12% 2099 139211 1% /
devfs 1 1 0 100% 0 0 100% /dev
/dev/twed0s1d 4058062 3264732 468686 87% 23045 518649 4% /tmp
/dev/twed0s1f 82042376 57488474 17990512 76% 2014718 8607232 19% /usr
/dev/twed0s1e 20308398 5173252 13510476 28% 1813 2636009 0% /var
0[nanobsd]#
After running the program and creating all the files, I just did a
reboot and all worked just fine post reboot.
Did you fill up the partition or run out of inodes perhaps ?
---Mike
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