Date: Mon, 01 Feb 2010 13:09:12 +0800 From: Eugene Teo <eugeneteo@...nel.sg> To: oss-security@...ts.openwall.com CC: "Steven M. Christey" <coley@...us.mitre.org> Subject: CVE request - kernel: DoS on x86_64 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 References: http://marc.info/?t=126466700200002&r=1&w=2 https://bugzilla.redhat.com/show_bug.cgi?id=560547 Thanks, Eugene
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