Messages in this thread Patch in this message | | | Date | Mon, 14 Jun 2004 15:20:01 +0100 | From | Nuno Monteiro <> | Subject | Re: Local DoS attack on i386 (was: new kernel bug) |
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On 2004.06.14 14:58, Gianni Tedesco wrote: > On Sat, 2004-06-12 at 11:59 +0200, Manuel Arostegui Ramirez wrote: > > Somebody know a patch to solved this new bug? > > http://reviewed.homelinux.org/news/2004-06-11_kernel_crash/index.html.en > > Affected versions: > > * Linux 2.6.x > > o Linux 2.6.7-rc2 > > o Linux 2.6.6 (all versions) > > o Linux 2.6.6 SMP (verified by riven) > > o Linux 2.6.5-gentoo (verified by RatiX) > > o Linux 2.6.5-mm6 - (verified by Mariux) > > * Linux 2.4.2x > > o Linux 2.4.26 vanilla > > o Linux 2.4.26-rc1 vanilla > > o Linux 2.4.26-gentoo-r1 > > o Linux 2.4.22 > > Seems to be a scheduler race or something? >
This was already fixed in 2.6, see http://linux.bkbits.net:8080/linux-2.5/diffs/include/asm-i386/i387.h@1.16?nav=index.html|src/.|src/include|src/include/asm-i386|hist/include/asm-i386/i387.h
The same fix should be applied to 2.4. I'm running locally a very hacked version of 2.4.22 with it and it survives that crash.c program.
Here's the diff. Marcelo, please merge.
--- linux-2.4.27-pre5/include/asm-i386/i387.h~fix-x86-clear_fpu-macro 2004-06-14 15:12:13.909059344 +0100 +++ linux-2.4.27-pre5/include/asm-i386/i387.h 2004-06-14 15:12:45.970185312 +0100 @@ -34,7 +34,7 @@ extern void kernel_fpu_begin(void); #define clear_fpu( tsk ) do { \ if ( tsk->flags & PF_USEDFPU ) { \ - asm volatile("fwait"); \ + asm volatile("fnclex ; fwait"); \ tsk->flags &= ~PF_USEDFPU; \ stts(); \ } \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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