Bug 1167248 has the long backstory, but the short story is the Windows' rand_s() can crash when some bad third-party software injects advapi32.dll hooks and Firefox has been built with VS2013. rand_s() just loads advapi32.dll and calls RtlGenRandom(). Instead we can just call RtlGenRandom() ourselves. Chrome did this with https://crbug.com/348400 and we did this in SpiderMonkey with bug 1167248. bp-a74be01f-edd6-432f-a19f-eae272160108 is one example of a crash in ipc/chromium's call to rand_s(). This patch imports the latest snapshot of Chromium's rand_util_win.cc, which no longer calls rand_s(), and copies the RandBytes() function prototype from rand_util.h. https://chromium.googlesource.com/chromium/src.git/+/8c37218a4cfa8725c0617db940f2d90b844f5023

Comment on attachment 8709147 [details] [diff] [review] import-RtlGenRandom-fix.patch Review of attachment 8709147 [details] [diff] [review]: ----------------------------------------------------------------- Looks good to me.

Thanks, Jed! Because this will fix some crashes seen in the field, I will ask for uplift after this change baked on Nightly for a couple days.

Comment on attachment 8709147 [details] [diff] [review] import-RtlGenRandom-fix.patch Approval Request Comment I fixed this crash in Nightly 46. I'd like to uplift this fix to 45, wherever that may be: Aurora 45 or Beta 45. :) [Feature/regressing bug #]: None [User impact if declined]: There were only 6 instances of this crash in the last 28 days, possibly from just 2 users. It is admittedly a very low frequency crash. https://crash-stats.mozilla.com/report/list?product=Firefox&range_unit=days&range_value=28&signature=invalid_parameter_noinfo+|+rand_s#tab-reports [Describe test coverage new/current, TreeHerder]: This patch has been baking on Nightly for 3 days. This crash happens in our mozilla-central fork of Chromium's IPC code. This patch just imports the latest snapshot of two short files from Chromium's upstream repo, where Google has worked around the crash. [Risks and why]: I think this is a low risk because this patch just imports Google's tested fix. [String/UUID change made/needed]: None

Comment on attachment 8709147 [details] [diff] [review] import-RtlGenRandom-fix.patch Fix a crash, taking it.