| ... | ... | @@ -48,6 +48,16 @@ const Context = struct { |
| 48 | 48 | gimli: std.crypto.core.Gimli, |
| 49 | 49 | }; |
| 50 | 50 | |
| 51 | var install_atfork_handler = std.once(struct { |
| 52 | // Install the global handler only once. |
| 53 | // The same handler is shared among threads and is inherinted by fork()-ed |
| 54 | // processes. |
| 55 | fn do() void { |
| 56 | const r = std.c.pthread_atfork(null, null, childAtForkHandler); |
| 57 | std.debug.assert(r == 0); |
| 58 | } |
| 59 | }.do); |
| 60 | |
| 51 | 61 | threadlocal var wipe_mem: []align(mem.page_size) u8 = &[_]u8{}; |
| 52 | 62 | |
| 53 | 63 | fn tlsCsprngFill(_: *const std.rand.Random, buffer: []u8) void { |
| ... | ... | @@ -107,13 +117,9 @@ fn tlsCsprngFill(_: *const std.rand.Random, buffer: []u8) void { |
| 107 | 117 | break :wof; |
| 108 | 118 | } else |_| {} |
| 109 | 119 | |
| 110 | | os.madvise( |
| 111 | | wipe_mem.ptr, |
| 112 | | wipe_mem.len, |
| 113 | | os.MADV_WIPEONFORK, |
| 114 | | ) catch { |
| 120 | if (os.madvise(wipe_mem.ptr, wipe_mem.len, os.MADV_WIPEONFORK)) |_| { |
| 115 | 121 | return initAndFill(buffer); |
| 116 | | }; |
| 122 | } else |_| {} |
| 117 | 123 | } |
| 118 | 124 | |
| 119 | 125 | if (std.Thread.use_pthreads) { |
| ... | ... | @@ -139,17 +145,14 @@ fn tlsCsprngFill(_: *const std.rand.Random, buffer: []u8) void { |
| 139 | 145 | } |
| 140 | 146 | |
| 141 | 147 | fn setupPthreadAtforkAndFill(buffer: []u8) void { |
| 142 | | const failed = std.c.pthread_atfork(null, null, childAtForkHandler) != 0; |
| 143 | | if (failed) { |
| 144 | | const ctx = @ptrCast(*Context, wipe_mem.ptr); |
| 145 | | ctx.init_state = .failed; |
| 146 | | return fillWithOsEntropy(buffer); |
| 147 | | } else { |
| 148 | | return initAndFill(buffer); |
| 149 | | } |
| 148 | install_atfork_handler.call(); |
| 149 | return initAndFill(buffer); |
| 150 | 150 | } |
| 151 | 151 | |
| 152 | 152 | fn childAtForkHandler() callconv(.C) void { |
| 153 | // The atfork handler is global, this function may be called after |
| 154 | // fork()-ing threads that never initialized the CSPRNG context. |
| 155 | if (wipe_mem.len == 0) return; |
| 153 | 156 | std.crypto.utils.secureZero(u8, wipe_mem); |
| 154 | 157 | } |
| 155 | 158 | |
Jakub Konka <kubkon@jakubkonka.com> 2021-05-20 16:53:24+02:00
GitHub <noreply@github.com> 2021-05-20 16:53:24+02:00
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lib