Bibliographic record
Abstract
We revisit the setuid family of calls for privilege management that is implemented in several widely-used operating systems. Three of the four commonly used calls in the family are standardized by POSIX. We investigate the current status of setuid, and in the process, challenge some assertions in prior work. We address three sets of questions with regards to the setuid family. (1) Is the POSIX standard indeed broken as prior work suggests? (2) Are implementations POSIX-compliant as claimed? (3) Are the wrapper functions that prior work proposes to circumvent issues with setuid calls correct and usable? Towards (1), we express the standards in a precise syntax that allows us to assess whether they are unambiguous, logically consistent descriptions of well-formed functions. We have discovered that two of the three functions that are standardized fit these criteria, thereby challenging assertions in prior work regarding the quality of the standard. In cases wherein the standard is broken, we give a clear characterization, and suggest that the standard can be fixed easily, but at the cost of backwards-compatibility. Towards (2), we perform a state-space enumeration as in prior work, report on our discoveries, and discuss the implications of non-conformance and differences in implementation. Towards (3), we discuss some issues that we have discovered with prior wrappers. We then propose a new suite of wrapper functions which are designed with a different mindset from prior work, and provide both stronger guarantees with respect to atomicity and a clearer semantics for permanent and temporary changes in process identity. With a fresh approach, our work is a contribution to a well-established approach to privilege management.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.018 | 0.034 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.007 | 0.008 |
| Scholarly communication | 0.016 | 0.030 |
| Open science | 0.003 | 0.016 |
| Research integrity | 0.005 | 0.012 |
| Insufficient payload (model declined to judge) | 0.019 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".