On Mon, Jan 26, 2015 at 03:43:46PM -0800, Andrew Morton wrote: > > > > Looks good to me, thanks! Though I would really appreciate if someone > > from security camp take a look as well. > > hm, who's that. Kees comes to mind. yup, I managed to forget CC him. > > And reviewers' task would be a heck of a lot easier if they knew what > /proc/pid/map_files actually does. This: > > akpm3:/usr/src/25> grep -r map_files Documentation > akpm3:/usr/src/25> > > does not help. Sigh. Imagine, for some reason I though we've the docs for that entry, probably i though that way because of many fdinfo snippets i've putted into /proc docs. my bad, sorry. I'll try to prepare docs today. > The 640708a2cff7f81 changelog says: > > : This one behaves similarly to the /proc/<pid>/fd/ one - it contains > : symlinks one for each mapping with file, the name of a symlink is > : "vma->vm_start-vma->vm_end", the target is the file. Opening a symlink > : results in a file that point exactly to the same inode as them vma's one. > : > : For example the ls -l of some arbitrary /proc/<pid>/map_files/ > : > : | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80403000-7f8f80404000 -> /lib64/libc-2.5.so > : | lr-x------ 1 root root 64 Aug 26 06:40 7f8f8061e000-7f8f80620000 -> /lib64/libselinux.so.1 > : | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80826000-7f8f80827000 -> /lib64/libacl.so.1.1.0 > : | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a2f000-7f8f80a30000 -> /lib64/librt-2.5.so > : | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a30000-7f8f80a4c000 -> /lib64/ld-2.5.so > > afacit this info is also available in /proc/pid/maps, so things > shouldn't get worse if the /proc/pid/map_files permissions are at least > as restrictive as the /proc/pid/maps permissions. Is that the case? > (Please add to changelog). > > There's one other problem here: we're assuming that the map_files > implementation doesn't have bugs. If it does have bugs then relaxing > permissions like this will create new vulnerabilities. And the > map_files implementation is surprisingly complex. Is it bug-free? I didn't find any bugs in map-files (and we use it for long time already) so I think it is safe. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
