From a5b30a508c47017fa585173a2ed4535484e86200 Mon Sep 17 00:00:00 2001
From: Edoardo Vacchi <evacchi@users.noreply.github.com>
Date: Thu, 24 Aug 2023 00:25:55 +0200
Subject: [PATCH] wasi: fix symlink-related issues with path handling (#1648)

Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
---
 experimental/sys/errno.go                 | 3 +++
 experimental/sys/syscall_errno.go         | 2 ++
 imports/wasi_snapshot_preview1/fs.go      | 7 +++++--
 imports/wasi_snapshot_preview1/fs_test.go | 4 ++--
 internal/wasip1/errno.go                  | 2 ++
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/experimental/sys/errno.go b/experimental/sys/errno.go
index 81baadd0d9..2389494960 100644
--- a/experimental/sys/errno.go
+++ b/experimental/sys/errno.go
@@ -35,6 +35,7 @@ const (
 	ENOENT
 	ENOSYS
 	ENOTDIR
+	ERANGE
 	ENOTEMPTY
 	ENOTSOCK
 	ENOTSUP
@@ -79,6 +80,8 @@ func (e Errno) Error() string {
 		return "functionality not supported"
 	case ENOTDIR:
 		return "not a directory or a symbolic link to a directory"
+	case ERANGE:
+		return "result too large"
 	case ENOTEMPTY:
 		return "directory not empty"
 	case ENOTSOCK:
diff --git a/experimental/sys/syscall_errno.go b/experimental/sys/syscall_errno.go
index 23c4be9283..d28f6faa03 100644
--- a/experimental/sys/syscall_errno.go
+++ b/experimental/sys/syscall_errno.go
@@ -40,6 +40,8 @@ func syscallToErrno(err error) (Errno, bool) {
 		return ENOSYS, true
 	case syscall.ENOTDIR:
 		return ENOTDIR, true
+	case syscall.ERANGE:
+		return ERANGE, true
 	case syscall.ENOTEMPTY:
 		return ENOTEMPTY, true
 	case syscall.ENOTSOCK:
diff --git a/imports/wasi_snapshot_preview1/fs.go b/imports/wasi_snapshot_preview1/fs.go
index b80c14d7d5..9d28ae17b0 100644
--- a/imports/wasi_snapshot_preview1/fs.go
+++ b/imports/wasi_snapshot_preview1/fs.go
@@ -7,7 +7,6 @@ import (
 	"math"
 	"path"
 	"strings"
-	"syscall"
 	"unsafe"
 
 	"github.com/tetratelabs/wazero/api"
@@ -1463,7 +1462,7 @@ func pathFilestatSetTimesFn(_ context.Context, mod api.Module, params []uint64)
 		return preopen.Utimens(pathName, atim, mtim)
 	}
 	// Otherwise, we need to emulate don't follow by opening the file by path.
-	if f, errno := preopen.OpenFile(pathName, syscall.O_WRONLY, 0); errno != 0 {
+	if f, errno := preopen.OpenFile(pathName, experimentalsys.O_WRONLY, 0); errno != 0 {
 		return errno
 	} else {
 		defer f.Close()
@@ -1797,6 +1796,10 @@ func pathReadlinkFn(_ context.Context, mod api.Module, params []uint64) experime
 		return errno
 	}
 
+	if len(dst) > int(bufLen) {
+		return experimentalsys.ERANGE
+	}
+
 	if ok := mem.WriteString(buf, dst); !ok {
 		return experimentalsys.EFAULT
 	}
diff --git a/imports/wasi_snapshot_preview1/fs_test.go b/imports/wasi_snapshot_preview1/fs_test.go
index a62195502d..fc23e89753 100644
--- a/imports/wasi_snapshot_preview1/fs_test.go
+++ b/imports/wasi_snapshot_preview1/fs_test.go
@@ -4238,12 +4238,12 @@ func Test_pathReadlink(t *testing.T) {
 			{expectedErrno: wasip1.ErrnoInval, bufLen: 100},
 			{
 				name:          "bufLen too short",
-				expectedErrno: wasip1.ErrnoFault,
+				expectedErrno: wasip1.ErrnoRange,
 				fd:            dirFD,
 				bufLen:        10,
 				path:          destinationPath,
 				pathLen:       uint32(len(destinationPathName)),
-				buf:           math.MaxUint32,
+				buf:           0,
 			},
 			{
 				name:          "path past memory",
diff --git a/internal/wasip1/errno.go b/internal/wasip1/errno.go
index b4af415083..701c2aa4f2 100644
--- a/internal/wasip1/errno.go
+++ b/internal/wasip1/errno.go
@@ -296,6 +296,8 @@ func ToErrno(errno sys.Errno) Errno {
 		return ErrnoNosys
 	case sys.ENOTDIR:
 		return ErrnoNotdir
+	case sys.ERANGE:
+		return ErrnoRange
 	case sys.ENOTEMPTY:
 		return ErrnoNotempty
 	case sys.ENOTSOCK: