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perlpilot / p6-File-Temp

Simple implementation of File::Temp for creating temporary files
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file mode #7

Open tokuhirom opened 8 years ago

tokuhirom commented 8 years ago

Created temporary file is world readable. It cause security issue.

$ perl6-m -e 'use File::Temp; my ($fname, $fh) = tempfile(); run "ls", "-l", $fname'
-rw-rw-r--. 1 tokuhirom tokuhirom 0 Oct 14 11:04 /tmp/v0lP7DvWlc

Perl5's code is readable by owner only.

$ perl -e 'use File::Temp qw/tempfile/; my ($fh, $fname) = tempfile(); system "ls", "-l", $fname'
-rw-------. 1 tokuhirom tokuhirom 0 Oct 14 11:05 /tmp/1qtbZFwofM
rudis commented 8 years ago

Seconded too. Secure defaults are very important, please change it.

perlpilot commented 8 years ago

Fixed for both files and directories in 7852c8d6e7536463f3e438d9753415d7018e2253

rudis commented 8 years ago

The commit contains a race condition and doesn't fix the bug. If the file is opened before the chmod, an attacker can still read the file contents even after the chmod.

To prevent the race condition please use the $mode argument for open() and mkdir(). If you like I can write a patch.

zoffixznet commented 8 years ago

@rudis any word on the patch? I can submit a fix, if you're busy.

zoffixznet commented 7 years ago

Looking at this 1 year later, I don't really see the race condition. The mode is set before the file is given to the user. Also, open doesn't have a mode argument.

EDIT: ah, OK, the race could let the attacker write crap into it, though doesn't look like this is solvable with Perl 6 IO at the moment.