[xfstests-bld] setup-buildchroot: fix copying passwd and group entries

Commit Message

Eric Biggers Aug. 31, 2017, 8:14 p.m. UTC

From: Eric Biggers <[e-mail]>

create_chroot() is now supposed to add $CHROOT_USER to /etc/passwd in
the chroot.  However, due to a bad grep pattern, it would add multiple
entries if $CHROOT_USER happened to be a suffix of another username.
Also the passwd record is not guaranteed to actually be in the file
/etc/passwd.  Fix it by using 'getent passwd $CHROOT_USER' instead.

A similar problem existed for the group entry, but also the
$CHROOT_USER's primary group is not guaranteed to have the same name as
the user.  Fix that by using 'id -g' to look up the primary group.

Signed-off-by: Eric Biggers <[e-mail]>
---
 setup-buildchroot | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Eric Biggers Sept. 16, 2017, 3:59 a.m. UTC | #1

On Thu, Aug 31, 2017 at 01:14:50PM -0700, Eric Biggers wrote:
> From: Eric Biggers <[e-mail]>
> 
> create_chroot() is now supposed to add $CHROOT_USER to /etc/passwd in
> the chroot.  However, due to a bad grep pattern, it would add multiple
> entries if $CHROOT_USER happened to be a suffix of another username.
> Also the passwd record is not guaranteed to actually be in the file
> /etc/passwd.  Fix it by using 'getent passwd $CHROOT_USER' instead.
> 
> A similar problem existed for the group entry, but also the
> $CHROOT_USER's primary group is not guaranteed to have the same name as
> the user.  Fix that by using 'id -g' to look up the primary group.
> 

Ted, can you apply this patch?  Thanks!

Eric
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Theodore Ts'o Sept. 16, 2017, 6:33 a.m. UTC | #2

On Fri, Sep 15, 2017 at 08:59:14PM -0700, Eric Biggers wrote:
> On Thu, Aug 31, 2017 at 01:14:50PM -0700, Eric Biggers wrote:
> > From: Eric Biggers <[e-mail]>
> > 
> > create_chroot() is now supposed to add $CHROOT_USER to /etc/passwd in
> > the chroot.  However, due to a bad grep pattern, it would add multiple
> > entries if $CHROOT_USER happened to be a suffix of another username.
> > Also the passwd record is not guaranteed to actually be in the file
> > /etc/passwd.  Fix it by using 'getent passwd $CHROOT_USER' instead.
> > 
> > A similar problem existed for the group entry, but also the
> > $CHROOT_USER's primary group is not guaranteed to have the same name as
> > the user.  Fix that by using 'id -g' to look up the primary group.
> > 
> 
> Ted, can you apply this patch?  Thanks!

Oops, missed this earlier; thanks for the ping.  I've applied it.

      	     	  	    	 	 - Ted
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Patch

diff --git a/setup-buildchroot b/setup-buildchroot
index 2340eb5..992a87c 100755
--- a/setup-buildchroot
+++ b/setup-buildchroot
@@ -524,8 +524,8 @@  EOF
 	chmod 1777 "$CHROOT_DIR/run/shm"
     fi
     if [ -n "$CHROOT_USER" ]; then
-	grep "$CHROOT_USER": /etc/passwd >> "$CHROOT_DIR/etc/passwd"
-	grep "$CHROOT_USER": /etc/group >> "$CHROOT_DIR/etc/group"
+	getent passwd "$CHROOT_USER" >> "$CHROOT_DIR/etc/passwd"
+	getent group "$(id -g "$CHROOT_USER")" >> "$CHROOT_DIR/etc/group"
 	run_in_chroot "adduser $CHROOT_USER sudo"
     fi
 }