Date: Wed, 3 Feb 2010 19:28:05 -0700 From: dann frazier <dannf@...ian.org> To: oss-security@...ts.openwall.com Cc: "Steven M. Christey" <coley@...us.mitre.org> Subject: Re: CVE request - kernel: DoS on x86_64 On Mon, Feb 01, 2010 at 01:09:12PM +0800, Eugene Teo wrote: > Reported by Mathias Krause. The problem seams to be located in > fs/binfmt_elf.c:load_elf_binary(). It calls SET_PERSONALITY() prior > checking that the ELF interpreter is available. This in turn makes the > previously 32 bit process a 64 bit one which would be fine if execve() > would succeed. But after the SET_PERSONALITY() the open_exec() call > fails (because it cannot find the interpreter) and execve() almost > instantly returns with an error. If you now look at /proc/PID/maps > you'll see, that it has the vsyscall page mapped which shouldn't be. But > the process is not dead yet, it's still running. By now generating a > segmentation fault and in turn trying to generate a core dump the > kernel just dies. > > Steps to Reproduce: > 1. Enable core dumps > 2. Start an 32 bit program that tries to execve() an 64 bit program > 3. The 64 bit program cannot be started by the kernel because it can't > find the interpreter, i.e. execve returns with an error > 4. Generate a segmentation fault > 5. panic > > Upstream commit: > http://git.kernel.org/linus/221af7f87b97431e3ee21ce4b0e77d5411cf1549 Thanks Eugene. Also note this fix for a regression in the above: http://git.kernel.org/linus/7ab02af428c2d312c0cf8fb0b01cc1eb21131a3d -- dann frazier
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