[Buildroot] Fighting with suid bit

Peter Korsgaard peter at korsgaard.com
Fri May 4 13:49:02 UTC 2018


>>>>> "kaneda" == kaneda  <kaneda at chez.com> writes:

 > Hi,
 > It seems you got something here....


 > /target
 > - ucon64 is 4755
 > - udevadm is 4755


 > rootfs.tar.gz
 > - ucon64 is 4755
 > - udevadm is 4755


 > rootfs.cpio
 > - ucon64 is 0755
 > - udevadm is 0755


 > As you can see, it's not only my own file, but also udevadm

What buildroot version are you on? I just did a quick test on 2018.02.x
with the following config:

# BR2_PACKAGE_BUSYBOX is not set
BR2_PACKAGE_IPUTILS=y
BR2_TARGET_ROOTFS_CPIO=y

(the iputils package has a few setuid binaries):

tar -tvf rootfs.tar | grep ping
-rwsr-xr-x 0/0           43264 2018-05-04 15:35 ./bin/ping
-rwxr-xr-x 0/0           12108 2018-05-04 15:35 ./sbin/arping

cpio -ivt < rootfs.cpio | grep ping
-rwxr-xr-x   1 root     root        12108 May  4 15:35 sbin/arping
-rwsr-xr-x   1 root     root        43264 May  4 15:35 bin/ping

So that looks sensible.

I also tried it on current master with the same results:

tar -tvf rootfs.tar | grep ping
-rwsr-xr-x 0/0           43264 2018-05-04 15:44 ./bin/ping
-rwxr-xr-x 0/0           12108 2018-05-04 15:44 ./sbin/arping

cpio -ivt < rootfs.cpio | grep ping
-rwxr-xr-x   1 root     root        12108 May  4 15:44 sbin/arping
-rwsr-xr-x   1 root     root        43264 May  4 15:44 bin/ping

-- 
Bye, Peter Korsgaard


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