crypto/internal/fips/check: fix for ASAN builds

For now, FIPS does not work with ASAN: ASAN detects reads
it doesn't like during the scans of memory done by verification.
It could be made to work if there was a way to disable ASAN
during verification, but that doesn't appear to be possible.

Instead of a cryptic ASAN message, panic with a clear error.
And disable the test during ASAN.

Fixes #70321.

Change-Id: Ibc3876836abb83248a23c18c3b44c4cbb4a0c600
Reviewed-on: https://go-review.googlesource.com/c/go/+/627603
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Russ Cox <rsc@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

diff --git a/src/crypto/internal/fips/check/check.go b/src/crypto/internal/fips/check/check.go
index 71405cdf7f0193f4dcc0ea721c5b457c7fb78d8d..9d1a88d78e1a4caacc1e227c6fcf814b018c78ac 100644 (file)
--- a/src/crypto/internal/fips/check/check.go
+++ b/src/crypto/internal/fips/check/check.go
@@ -15,6 +15,7 @@ package check
 import (
        "crypto/internal/fips/hmac"
        "crypto/internal/fips/sha256"
+       "internal/asan"
        "internal/byteorder"
        "internal/godebug"
        "io"
@@ -77,6 +78,17 @@ func init() {
                return
        }
 
+       if asan.Enabled {
+               // ASAN disapproves of reading swaths of global memory below.
+               // One option would be to expose runtime.asanunpoison through
+               // crypto/internal/fipsdeps and then call it to unpoison the range
+               // before reading it, but it is unclear whether that would then cause
+               // false negatives. For now, FIPS+ASAN doesn't need to work.
+               // If this is made to work, also re-enable the test in check_test.go.
+               panic("fips140: cannot verify in asan mode")
+               return
+       }
+
        switch v {
        case "on", "only", "debug":
                // ok

diff --git a/src/crypto/internal/fips/check/check_test.go b/src/crypto/internal/fips/check/check_test.go
index 56d7a1950326b0c9949a90e5de05fd6269af242d..f0ca7f42511f5d80fbb7850726fac003a6ee7377 100644 (file)
--- a/src/crypto/internal/fips/check/check_test.go
+++ b/src/crypto/internal/fips/check/check_test.go
@@ -9,6 +9,7 @@ import (
        "crypto/internal/fips/check/checktest"
        "fmt"
        "internal/abi"
+       "internal/asan"
        "internal/godebug"
        "os"
        "os/exec"
@@ -37,6 +38,11 @@ func TestVerify(t *testing.T) {
        if !Supported() {
                t.Skipf("skipping on %s-%s", runtime.GOOS, runtime.GOARCH)
        }
+       if asan.Enabled {
+               // Verification panics with asan; don't bother.
+               t.Skipf("skipping with -asan")
+               return
+       }
 
        cmd := exec.Command(os.Args[0], "-test.v")
        cmd.Env = append(cmd.Environ(), "GODEBUG=fips140=on")

diff --git a/src/crypto/internal/fips/check/checktest/asm.s b/src/crypto/internal/fips/check/checktest/asm.s
index 1151a1345bda3763e31f518dde58dbce451e5e5b..090f87b1ec5c3d2ac8958c9c8119b9ab1c8c7b36 100644 (file)
--- a/src/crypto/internal/fips/check/checktest/asm.s
+++ b/src/crypto/internal/fips/check/checktest/asm.s
@@ -2,5 +2,5 @@
 
 #include "textflag.h"
 
-DATA ·RODATA(SB)/4, $2
-GLOBL ·RODATA(SB), RODATA, $4
+DATA crypto∕internal∕fips∕check∕checktest·RODATA(SB)/4, $2
+GLOBL crypto∕internal∕fips∕check∕checktest·RODATA(SB), RODATA, $4

diff --git a/src/crypto/internal/fips/check/checktest/test.go b/src/crypto/internal/fips/check/checktest/test.go
index b234316d7aeb58e779299d266778cc3671ddc580..84d92332b556a92aae28fa3e909f6bd64521c14a 100644 (file)
--- a/src/crypto/internal/fips/check/checktest/test.go
+++ b/src/crypto/internal/fips/check/checktest/test.go
@@ -6,10 +6,17 @@
 // the crypto/internal/fips/check test.
 package checktest
 
-import _ "crypto/internal/fips/check"
+import (
+       _ "crypto/internal/fips/check"
+       _ "unsafe" // go:linkname
+)
 
 var NOPTRDATA int = 1
 
+// The linkname here disables asan registration of this global,
+// because asan gets mad about rodata globals.
+//
+//go:linkname RODATA crypto/internal/fips/check/checktest.RODATA
 var RODATA int32 // set to 2 in asm.s
 
 // DATA needs to have both a pointer and an int so that _some_ of it gets