First published: Tue Jan 12 2010(Updated: )
Description of problem: When print-fatal-signals is enabled it's possible to dump any memory reachable by the kernel to the log by simply jumping to that address from user space. Or crash the system if there's some hardware with read side effects. The fatal signals handler will dump 16 bytes at the execution address, which is fully controlled by ring 3. In addition when something jumps to a unmapped address there will be up to 16 additional useless page faults, which might be potentially slow (and at least is not very efficient) Fortunately this option is off by default and only there on i386. But fix it by checking for kernel addresses and also stopping when there's a page fault. References: <a href="http://patchwork.kernel.org/patch/69752/">http://patchwork.kernel.org/patch/69752/</a> <a href="http://git.kernel.org/linus/b45c6e76bc2c72f6426c14bed64fdcbc9bf37cb0">http://git.kernel.org/linus/b45c6e76bc2c72f6426c14bed64fdcbc9bf37cb0</a>
Credit: secalert@redhat.com
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Linux kernel | <2.6.32.4 | |
Debian Debian Linux | =5.0 | |
Debian Debian Linux | =4.0 |
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