Hi Martin, Martin Pitt wrote: > Eugene Teo [2007-07-29 21:03 +0800]: >>>> Also, it is probably good to think how we can "drop privileges" while >>>> piping >>>> the core dump output to an external program. A malicious user can >>>> potentially >>>> use it as a possible backdoor since anything that is executed by >>>> "|program" will >>>> be executed with root privileges. >>>> >>> It was my understanding that apport already did this. >> I haven't looked at apport yet, but are you talking about the userspace >> portion of >> apport or the kernel changes in the Ubuntu kernel? > > Similarly to Neil's patches, the Ubuntu kernel calls the userspace > helper as root, too. Apport drops privileges to the target process as > soon as possible (there are a few things it needs to do before, like > opening an fd to the crash file in /var/crash/ if that is only > writeable by root).
Just sharing some thoughts. Wouldn't it be more logical to drop the privileges first, then call the userspace helper program? I know that this will limit tools like apport to be able to read and/or write files that are only writable by root, but there ought to be a better way to do this? What if the program piped is not a legitimate program? Also, maybe it is good to make this portion of the code optional too, so that if no one is using this "ispipe" feature, we just turn it off. Eugene - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
