eix-remote fails to create temporary directory on pambase[mktemp] system

[waptaff]

Hi.

The mktemp flag on sys-auth/pambase allows the per-user /tmp directory feature (for instance, user fred has TMP and TMPDIR set to /tmp/.private/fred).

Running eix-remote as root gives this error:

mktemp: failed to create directory via template ‘/tmp/.private/root/eix-remote.XXXXXXXX’: Permission denied
 * cannot create temporary directory

I suspect this error is happening because eix-drop-permissions does not involve PAM hence does not reset TMP and TMPDIR.

Perhaps the ${TMPDIR:-/tmp} constructs in /usr/share/eix/eix-functions should be updated to first check if TMPDIR is read/writable.

[vaeth]

It is the caller's responsibility to pass a sane value as TMPDIR. Trying to outsmart the user by re-interpreting that value is calling for trouble and perhaps even opens some attack surface on some systems due to such surprising behavior.

[sprig]

getting the same problem.

not sure if the answer makes sense - the TMPDIR is set for the (root) user, but the permission drop effectively changes it while still using the privileged user’s dir.

regardless, for other readers; as a workaround running TMPDIR=/tmp eix-update works for me.

[baybal]

It is the caller's responsibility to pass a sane value as TMPDIR. Trying to outsmart the user by re-interpreting that value is calling for trouble and perhaps even opens some attack surface on some systems due to such surprising behavior.

But that's kind of logical that TMPDIR pointing to an intentionally made private directory becomes read-only after the drop of privileges

[vaeth]

It is the caller's responsibility to pass a sane value as TMPDIR. Trying to outsmart the user by re-interpreting that value is calling for trouble and perhaps even opens some attack surface on some systems due to such surprising behavior.

But that's kind of logical that TMPDIR pointing to an intentionally made private directory becomes read-only after the drop of privileges

Sure. It is a logical consequence of the pam hack to make TMPDIR not world readable/writable/executable, as it is traditional under unix. That's why I say that it is the caller's responsibility to pass a sane value.

TMPDIR=/tmp eix-remote

should work (if /tmp is world read/writable/executable). Depending on your shell, you can put that into a shell function (or script or alias). You might have to use the full path to eix-remote (and add "$@") if you use a function or script which is also called eix-remote to avoid endless recursion.