From e541ebec2fdb5b29209cb3fc8235b77edcaebb6a Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Wed, 25 Mar 2020 14:54:10 -0700
Subject: Misc fixes to make stat_test pass (almost)

The only test failing now requires socket which is not
available in VFS2 yet.

Updates #1198

PiperOrigin-RevId: 302976572
---
 pkg/sentry/syscalls/linux/vfs2/BUILD         | 1 +
 pkg/sentry/syscalls/linux/vfs2/filesystem.go | 2 +-
 pkg/sentry/syscalls/linux/vfs2/getdents.go   | 4 ++--
 pkg/sentry/syscalls/linux/vfs2/stat.go       | 7 ++++++-
 4 files changed, 10 insertions(+), 4 deletions(-)

(limited to 'pkg/sentry/syscalls/linux/vfs2')

diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD
index e7695e995..2eb210014 100644
--- a/pkg/sentry/syscalls/linux/vfs2/BUILD
+++ b/pkg/sentry/syscalls/linux/vfs2/BUILD
@@ -31,6 +31,7 @@ go_library(
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/bits",
         "//pkg/fspath",
         "//pkg/gohacks",
         "//pkg/sentry/arch",
diff --git a/pkg/sentry/syscalls/linux/vfs2/filesystem.go b/pkg/sentry/syscalls/linux/vfs2/filesystem.go
index fc5ceea4c..a859095e2 100644
--- a/pkg/sentry/syscalls/linux/vfs2/filesystem.go
+++ b/pkg/sentry/syscalls/linux/vfs2/filesystem.go
@@ -250,7 +250,7 @@ func rmdirat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr) error {
 	if err != nil {
 		return err
 	}
-	tpop, err := getTaskPathOperation(t, dirfd, path, disallowEmptyPath, followFinalSymlink)
+	tpop, err := getTaskPathOperation(t, dirfd, path, disallowEmptyPath, nofollowFinalSymlink)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/sentry/syscalls/linux/vfs2/getdents.go b/pkg/sentry/syscalls/linux/vfs2/getdents.go
index ddc140b65..a61cc5059 100644
--- a/pkg/sentry/syscalls/linux/vfs2/getdents.go
+++ b/pkg/sentry/syscalls/linux/vfs2/getdents.go
@@ -97,7 +97,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error {
 		//     char           d_name[]; /* Filename (null-terminated) */
 		// };
 		size := 8 + 8 + 2 + 1 + 1 + len(dirent.Name)
-		if size < cb.remaining {
+		if size > cb.remaining {
 			return syserror.EINVAL
 		}
 		buf = cb.t.CopyScratchBuffer(size)
@@ -125,7 +125,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error {
 			panic(fmt.Sprintf("unsupported sizeof(unsigned long): %d", cb.t.Arch().Width()))
 		}
 		size := 8 + 8 + 2 + 1 + 1 + 1 + len(dirent.Name)
-		if size < cb.remaining {
+		if size > cb.remaining {
 			return syserror.EINVAL
 		}
 		buf = cb.t.CopyScratchBuffer(size)
diff --git a/pkg/sentry/syscalls/linux/vfs2/stat.go b/pkg/sentry/syscalls/linux/vfs2/stat.go
index 068243132..fdfe49243 100644
--- a/pkg/sentry/syscalls/linux/vfs2/stat.go
+++ b/pkg/sentry/syscalls/linux/vfs2/stat.go
@@ -16,6 +16,7 @@ package vfs2
 
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/bits"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/gohacks"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
@@ -153,7 +154,11 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
 	if flags&^(linux.AT_EMPTY_PATH|linux.AT_SYMLINK_NOFOLLOW|linux.AT_STATX_SYNC_TYPE) != 0 {
 		return 0, nil, syserror.EINVAL
 	}
-
+	// Make sure that only one sync type option is set.
+	syncType := uint32(flags & linux.AT_STATX_SYNC_TYPE)
+	if syncType != 0 && !bits.IsPowerOfTwo32(syncType) {
+		return 0, nil, syserror.EINVAL
+	}
 	if mask&linux.STATX__RESERVED != 0 {
 		return 0, nil, syserror.EINVAL
 	}
-- 
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