diff options
| author | Shenghou Ma <minux@golang.org> | 2016-04-05 23:09:39 -0400 |
|---|---|---|
| committer | Minux Ma <minux@golang.org> | 2016-04-06 04:23:37 +0000 |
| commit | a2eded3421f144983c0ccb9e6c0a325fa1ba1f82 (patch) | |
| tree | 04d3f62dfc749967cf69dd3d93737d9f4c884ca9 /src/runtime | |
| parent | db9348b866775974b5e04eed04c03de47f1c2d46 (diff) | |
| download | go-a2eded3421f144983c0ccb9e6c0a325fa1ba1f82.tar.xz | |
runtime: get randomness from AT_RANDOM AUXV on linux/arm64
Fixes #15147.
Change-Id: Ibfe46c747dea987787a51eb0c95ccd8c5f24f366
Reviewed-on: https://go-review.googlesource.com/21580
Run-TryBot: Minux Ma <minux@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/os_linux_arm64.go | 26 | ||||
| -rw-r--r-- | src/runtime/vdso_none.go | 1 |
2 files changed, 27 insertions, 0 deletions
diff --git a/src/runtime/os_linux_arm64.go b/src/runtime/os_linux_arm64.go index 3f994f128b..57184b0d3a 100644 --- a/src/runtime/os_linux_arm64.go +++ b/src/runtime/os_linux_arm64.go @@ -4,6 +4,11 @@ package runtime +import ( + "runtime/internal/sys" + "unsafe" +) + const ( _AT_NULL = 0 _AT_RANDOM = 25 // introduced in 2.6.29 @@ -11,6 +16,27 @@ const ( var randomNumber uint32 +func sysargs(argc int32, argv **byte) { + // skip over argv, envv to get to auxv + n := argc + 1 + for argv_index(argv, n) != nil { + n++ + } + n++ + auxv := (*[1 << 29]uint64)(add(unsafe.Pointer(argv), uintptr(n)*sys.PtrSize)) + + for i := 0; auxv[i] != _AT_NULL; i += 2 { + switch auxv[i] { + case _AT_RANDOM: // kernel provides a pointer to 16-bytes worth of random data + startupRandomData = (*[16]byte)(unsafe.Pointer(uintptr(auxv[i+1])))[:] + // the pointer provided may not be word aligned, so we must treat it + // as a byte array. + randomNumber = uint32(startupRandomData[4]) | uint32(startupRandomData[5])<<8 | + uint32(startupRandomData[6])<<16 | uint32(startupRandomData[7])<<24 + } + } +} + //go:nosplit func cputicks() int64 { // Currently cputicks() is used in blocking profiler and to seed fastrand1(). diff --git a/src/runtime/vdso_none.go b/src/runtime/vdso_none.go index b4e0a0e349..e14e1a4707 100644 --- a/src/runtime/vdso_none.go +++ b/src/runtime/vdso_none.go @@ -5,6 +5,7 @@ // +build !linux !amd64 // +build !linux !386 // +build !linux !arm +// +build !linux !arm64 package runtime |