feat: re-seed from system randomness on collision #314
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Re-seed thread-local RNG from system randomness if we run into a temporary file-name collision. This should address the concerns about using a predictable RNG without hurting performance in the common case where nobody is trying to predict our filenames. I'm only re-seeding once because if we _still_ fail to create a temporary file, the collision was likely due to too many temporary files instead of an attacker predicting our random temporary file names. I've also reduced the number of tries from 2^31 to 2^16. If it takes more than that to create a temporary file, something else is wrong. Pausing for a long time is usually worse than just failing. fixes #178
Stebalien
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Alternative to #311 (this patch includes a few miscellaneous documentation fixes from that PR as well). The previous documentation didn't sufficiently cover permissions issues and mixed all the security concerns into a single section. This patch separates things out into separate sections and hopefully makes all this easier to understand. This patch also documents the DOS mitigation introduced in #314. I've also removed the link to the OWASP documentation to avoid confusing users (their documentation is mostly concerned with low-level C and platform-specific temporary file creation functions).
This was referenced Jan 3, 2025
Stebalien
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Alternative to #311 (this patch includes a few miscellaneous documentation fixes from that PR as well). The previous documentation didn't sufficiently cover permissions issues and mixed all the security concerns into a single section. This patch separates things out into separate sections and hopefully makes all this easier to understand. This patch also documents the DOS mitigation introduced in #314. I've also removed the link to the OWASP documentation to avoid confusing users (their documentation is mostly concerned with low-level C and platform-specific temporary file creation functions).
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Re-seed thread-local RNG from system randomness if we run into a temporary file-name collision. This should address the concerns about using a predictable RNG without hurting performance in the common case where nobody is trying to predict our filenames. I'm only re-seeding once because if we still fail to create a temporary file, the collision was likely due to too many temporary files instead of an attacker predicting our random temporary file names.
I've also reduced the number of tries from 2^31 to 2^16. If it takes more than that to create a temporary file, something else is wrong. Pausing for a long time is usually worse than just failing.
fixes #178