runtime, syscall: use the new get_random_bytes syscall for NaCl

The SecureRandom named service was removed in
https://codereview.chromium.org/550523002. And the new syscall
was introduced in https://codereview.chromium.org/537543003.

Accepting this will remove the support for older version of
sel_ldr. I've confirmed that both pepper_40 and current
pepper_canary have this syscall.

After this change, we need sel_ldr from pepper_39 or above to
work.

Fixes #9261

Change-Id: I096973593aa302ade61f259a3a71ebc7c1a57913
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/1755
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

misc/nacl/README

@@ -8,7 +8,7 @@ Go 1.3 supports three architectures
 
  * nacl/386 which is standard 386.
  * nacl/amd64p32 which is a 64 bit architecture, where the address space is
-   limited to a 4gb window. 
+   limited to a 4gb window.
  * nacl/arm which is 32-bit ARMv7A architecture with 1GB address space.
 
 For background it is recommended that you read http://golang.org/s/go13nacl.
@@ -37,21 +37,20 @@ sdk. These are released every 6-8 weeks, in line with Chrome releases.
 	% cd /opt/nacl_sdk
 	% ./naclsdk update
 
-At this time pepper_34 is the stable version. If naclsdk downloads a later
-version, please adjust accordingly. As of June 2014, only the canary sdk
-provides support for nacl/arm.
+At this time pepper_40 is the stable version. The NaCl port needs at least pepper_39
+to work. If naclsdk downloads a later version, please adjust accordingly.
 
 The cmd/go helper scripts expect that the loaders sel_ldr_{x86_{32,64},arm} and
 nacl_helper_bootstrap_arm are in your path. I find it easiest to make a symlink
 from the NaCl distribution to my $GOPATH/bin directory.
 
-	% ln -nfs /opt/nacl_sdk/pepper_34/tools/sel_ldr_x86_32 $GOPATH/bin/sel_ldr_x86_32
-	% ln -nfs /opt/nacl_sdk/pepper_34/tools/sel_ldr_x86_64 $GOPATH/bin/sel_ldr_x86_64
-	% ln -nfs /opt/nacl_sdk/pepper_canary/tools/sel_ldr_arm $GOPATH/bin/sel_ldr_arm
+	% ln -nfs /opt/nacl_sdk/pepper_39/tools/sel_ldr_x86_32 $GOPATH/bin/sel_ldr_x86_32
+	% ln -nfs /opt/nacl_sdk/pepper_39/tools/sel_ldr_x86_64 $GOPATH/bin/sel_ldr_x86_64
+	% ln -nfs /opt/nacl_sdk/pepper_39/tools/sel_ldr_arm $GOPATH/bin/sel_ldr_arm
 
 Additionally, for NaCl/ARM only:
 
-	% ln -nfs /opt/nacl_sdk/pepper_canary/tools/nacl_helper_bootstrap_arm $GOPATH/bin/nacl_helper_bootstrap_arm 
+	% ln -nfs /opt/nacl_sdk/pepper_39/tools/nacl_helper_bootstrap_arm $GOPATH/bin/nacl_helper_bootstrap_arm
 
 Support scripts
 ---------------
@@ -110,7 +109,7 @@ Then, run the program as:
 
 The -g flag instructs the loader to stop at startup. Then, in another console:
 
-	% /opt/nacl_sdk/pepper_34/toolchain/linux_x86_glibc/bin/x86_64-nacl-gdb
+	% /opt/nacl_sdk/pepper_39/toolchain/linux_x86_glibc/bin/x86_64-nacl-gdb
 	% nacl-manifest mybin.manifest
 	% target remote :4014
 
@@ -118,5 +117,5 @@ If you see that the program is stopped in _rt0_amd64p32_nacl, then symbols are
 loaded successfully and you can type 'c' to start the program.
 Next time you can automate it as:
 
-	% /opt/nacl_sdk/pepper_34/toolchain/linux_x86_glibc/bin/x86_64-nacl-gdb \
+	% /opt/nacl_sdk/pepper_39/toolchain/linux_x86_glibc/bin/x86_64-nacl-gdb \
 		-ex 'nacl-manifest mybin.manifest' -ex 'target remote :4014'

src/runtime/os1_nacl.go

@@ -46,11 +46,8 @@ func crash() {
 	*(*int32)(nil) = 0
 }
 
-//go:nosplit
-func getRandomData(r []byte) {
-	// TODO: does nacl have a random source we can use?
-	extendRandom(r, 0)
-}
+//go:noescape
+func getRandomData([]byte)
 
 func goenvs() {
 	goenvs_unix()

src/runtime/sys_nacl_386.s

@@ -362,3 +362,12 @@ ret:
 	// 36(BP) is saved EFLAGS, never to be seen again
 	MOVL	32(BP), BP // saved PC
 	JMP	BP
+
+// func getRandomData([]byte)
+TEXT runtime·getRandomData(SB),NOSPLIT,$8-12
+	MOVL buf+0(FP), AX
+	MOVL AX, 0(SP)
+	MOVL len+4(FP), AX
+	MOVL AX, 4(SP)
+	NACL_SYSCALL(SYS_get_random_bytes)
+	RET

src/runtime/sys_nacl_amd64p32.s

@@ -412,6 +412,13 @@ nog:
 // cannot do real signal handling yet, because gsignal has not been allocated.
 MOVL $1, DI; NACL_SYSCALL(SYS_exit)
 
+// func getRandomData([]byte)
+TEXT runtime·getRandomData(SB),NOSPLIT,$0-12
+	MOVL buf+0(FP), DI
+	MOVL len+4(FP), SI
+	NACL_SYSCALL(SYS_get_random_bytes)
+	RET
+
 TEXT runtime·nacl_sysinfo(SB),NOSPLIT,$16
 /*
 	MOVL	di+0(FP), DI

src/runtime/sys_nacl_arm.s

@@ -301,6 +301,13 @@ nog:
 TEXT runtime·nacl_sysinfo(SB),NOSPLIT,$16
 	RET
 
+// func getRandomData([]byte)
+TEXT runtime·getRandomData(SB),NOSPLIT,$0-12
+	MOVW buf+0(FP), R0
+	MOVW len+4(FP), R1
+	NACL_SYSCALL(SYS_get_random_bytes)
+	RET
+
 TEXT runtime·casp1(SB),NOSPLIT,$0
 	B	runtime·cas(SB)
 

src/runtime/syscall_nacl.h

@@ -8,10 +8,10 @@
 #define SYS_read 12
 #define SYS_write 13
 #define SYS_lseek 14
-#define SYS_ioctl 15
 #define SYS_stat 16
 #define SYS_fstat 17
 #define SYS_chmod 18
+#define SYS_isatty 19
 #define SYS_brk 20
 #define SYS_mmap 21
 #define SYS_munmap 22
@@ -69,3 +69,16 @@
 #define SYS_test_crash 110
 #define SYS_test_syscall_1 111
 #define SYS_test_syscall_2 112
+#define SYS_futex_wait_abs 120
+#define SYS_futex_wake 121
+#define SYS_pread 130
+#define SYS_pwrite 131
+#define SYS_truncate 140
+#define SYS_lstat 141
+#define SYS_link 142
+#define SYS_rename 143
+#define SYS_symlink 144
+#define SYS_access 145
+#define SYS_readlink 146
+#define SYS_utimes 147
+#define SYS_get_random_bytes 150

src/syscall/fs_nacl.go

@@ -772,29 +772,24 @@ func (f *zeroFile) pread(b []byte, offset int64) (int, error) {
 	return len(b), nil
 }
 
-type randomFile struct {
-	naclFD int
-}
+type randomFile struct{}
 
 func openRandom() (devFile, error) {
-	fd, err := openNamedService("SecureRandom", O_RDONLY)
-	if err != nil {
-		return nil, err
-	}
-	return &randomFile{naclFD: fd}, nil
+	return randomFile{}, nil
 }
 
-func (f *randomFile) close() error {
-	naclClose(f.naclFD)
-	f.naclFD = -1
+func (f randomFile) close() error {
 	return nil
 }
 
-func (f *randomFile) pread(b []byte, offset int64) (int, error) {
-	return naclRead(f.naclFD, b)
+func (f randomFile) pread(b []byte, offset int64) (int, error) {
+	if err := naclGetRandomBytes(b); err != nil {
+		return 0, err
+	}
+	return len(b), nil
 }
 
-func (f *randomFile) pwrite(b []byte, offset int64) (int, error) {
+func (f randomFile) pwrite(b []byte, offset int64) (int, error) {
 	return 0, EPERM
 }
 

src/syscall/syscall_nacl.go

@@ -14,6 +14,7 @@ import (
 //sys	naclFstat(fd int, stat *Stat_t) (err error) = sys_fstat
 //sys	naclRead(fd int, b []byte) (n int, err error) = sys_read
 //sys	naclSeek(fd int, off *int64, whence int) (err error) = sys_lseek
+//sys	naclGetRandomBytes(b []byte) (err error) = sys_get_random_bytes
 
 const direntSize = 8 + 8 + 2 + 256
 

src/syscall/tables_nacl.go

@@ -15,10 +15,10 @@ const (
 	sys_read                 = 12
 	sys_write                = 13
 	sys_lseek                = 14
-	sys_ioctl                = 15
 	sys_stat                 = 16
 	sys_fstat                = 17
 	sys_chmod                = 18
+	sys_isatty               = 19
 	sys_brk                  = 20
 	sys_mmap                 = 21
 	sys_munmap               = 22
@@ -76,6 +76,19 @@ const (
 	sys_test_crash           = 110
 	sys_test_syscall_1       = 111
 	sys_test_syscall_2       = 112
+	sys_futex_wait_abs       = 120
+	sys_futex_wake           = 121
+	sys_pread                = 130
+	sys_pwrite               = 131
+	sys_truncate             = 140
+	sys_lstat                = 141
+	sys_link                 = 142
+	sys_rename               = 143
+	sys_symlink              = 144
+	sys_access               = 145
+	sys_readlink             = 146
+	sys_utimes               = 147
+	sys_get_random_bytes     = 150
 )
 
 // TODO: Auto-generate some day. (Hard-coded in binaries so not likely to change.)

src/syscall/zsyscall_nacl_386.go

@@ -61,3 +61,19 @@ func naclSeek(fd int, off *int64, whence int) (err error) {
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func naclGetRandomBytes(b []byte) (err error) {
+	var _p0 unsafe.Pointer
+	if len(b) > 0 {
+		_p0 = unsafe.Pointer(&b[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := Syscall(sys_get_random_bytes, uintptr(_p0), uintptr(len(b)), 0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}

src/syscall/zsyscall_nacl_amd64p32.go

@@ -61,3 +61,19 @@ func naclSeek(fd int, off *int64, whence int) (err error) {
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func naclGetRandomBytes(b []byte) (err error) {
+	var _p0 unsafe.Pointer
+	if len(b) > 0 {
+		_p0 = unsafe.Pointer(&b[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := Syscall(sys_get_random_bytes, uintptr(_p0), uintptr(len(b)), 0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}

src/syscall/zsyscall_nacl_arm.go

@@ -61,3 +61,19 @@ func naclSeek(fd int, off *int64, whence int) (err error) {
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func naclGetRandomBytes(b []byte) (err error) {
+	var _p0 unsafe.Pointer
+	if len(b) > 0 {
+		_p0 = unsafe.Pointer(&b[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := Syscall(sys_get_random_bytes, uintptr(_p0), uintptr(len(b)), 0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}