whither 1.00's "passwd -p ..." ?

[Paul Fox]

vda wrote:
 > 
 > piping password is indeed safe(r) since it is not visible in ps
 > (echo is sheel internal builtin and won't show up in ps either).

a while ago we thought we had need of the password-from-stdin
feature, and i did manage to get busybox passwd to do it, though
i don't recommend it.  i include it here for your amusement, or
horror, as you wish.  this is mail i sent to a colleage at the
time:

i wrote:
 > the reason the busybox passwd command doesn't work when the passwords
 > are on stdin like this:
 >     echo -e 'thistest\nthistest' | passwd root
 > 
 > is that because stdin isn't line-buffered, the whole string, including
 > the newline, is consumed in answer to the first "Enter new password:"
 > prompt, so there's nothing left for the "Re-enter new password:" prompt.
 > 
 > however, busybox does truncate the response at the newline.  so
 > to get it to work (WARNING!  this is REALLY REALLY UGLY), you "simply"
 > cause the first read() to be exactly satisfied with the first response,
 > and provide the second response after that.  the read() size in
 > this version of busybox is 255, so this command:
 >     (echo -e 
 > 'xyzzy\njjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
 > jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
 > jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
 > jjjjjjjjjjjjjjjj'; echo xyzzy) | passwd root
 >
 > does reset the password.  (that's enough 'j's to make the
 > first echo produce exactly 255 characters.)
 > 
 > the latest busybox has unchanged behavior, except the the buffer
 > is shorter -- only 63 characters total.  so (unsurprisingly) a
 > script based on this technique would not survive a busybox
 > upgrade.

in the end, we decided we didn't need the feature, so i'm afraid
i have no patch to offer, in compensation for making you read the
above atrocious solution.  :-)

paul
=---------------------
 paul fox, pgf at brightstareng.com