Mario Domenech Goulart <[email protected]> writes: > Hi Daniel, > > On Thu, 17 Sep 2026 00:13:19 -0400 Daniel Colascione via Chicken-users > <[email protected]> wrote: > >> create-temporary-file generates a candidate filename, checks whether it >> exists, and if it doesn't, opens the file in non-exclusive, write, and >> truncate mode. This strategy creates a TOCTOU race and can result in the >> calling process being tricked into truncating files or following >> symlinks it shouldn't. The generated name has too little entropy to make >> guessing infeasible. create-temporary-file should omit the existence >> check and open the generated file using O_EXCL, retrying on EEXIST. >> >> Better yet would be to call mkstemp(3), which addresses these issues >> and others. >> >> create-temporary-directory has a similar race, but because mkdir is >> always exclusive, race failures cause spurious errors instead of >> potentially unwanted file IO. It should retry on collision. > > Thanks for bringing this up. We have > https://bugs.call-cc.org/ticket/tf5/f598bc17026468d3b75cbe36589b2f0321f72fa1/ > for this issue
It's been open for twelve years. What's involved in fixing it?
