From d9a3f5d0c7d675b3cb4519eccca341bac33456af Mon Sep 17 00:00:00 2001
From: Dean Deng <deandeng@google.com>
Date: Thu, 23 Jul 2020 18:46:10 -0700
Subject: Add permission checks to vfs2 truncate.
- Check write permission on truncate(2). Unlike ftruncate(2),
truncate(2) fails if the user does not have write permissions
on the file.
- For gofers under InteropModeShared, check file type before
making a truncate request. We should fail early and avoid
making an rpc when possible. Furthermore, depending on the
remote host's failure may give us unexpected behavior--if the
host converts the truncate request to an ftruncate syscall on
an open fd, we will get EINVAL instead of EISDIR.
Updates #2923.
PiperOrigin-RevId: 322913569
---
pkg/sentry/fsimpl/tmpfs/filesystem.go | 2 +-
pkg/sentry/fsimpl/tmpfs/tmpfs.go | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
(limited to 'pkg/sentry/fsimpl/tmpfs')
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index a0f20c2d4..ef210a69b 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -649,7 +649,7 @@ func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts
fs.mu.RUnlock()
return err
}
- if err := d.inode.setStat(ctx, rp.Credentials(), &opts.Stat); err != nil {
+ if err := d.inode.setStat(ctx, rp.Credentials(), &opts); err != nil {
fs.mu.RUnlock()
return err
}
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index d7f4f0779..2545d88e9 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -452,7 +452,8 @@ func (i *inode) statTo(stat *linux.Statx) {
}
}
-func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx) error {
+func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, opts *vfs.SetStatOptions) error {
+ stat := &opts.Stat
if stat.Mask == 0 {
return nil
}
@@ -460,7 +461,7 @@ func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linu
return syserror.EPERM
}
mode := linux.FileMode(atomic.LoadUint32(&i.mode))
- if err := vfs.CheckSetStat(ctx, creds, stat, mode, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil {
+ if err := vfs.CheckSetStat(ctx, creds, opts, mode, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil {
return err
}
i.mu.Lock()
@@ -695,7 +696,7 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu
func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
creds := auth.CredentialsFromContext(ctx)
d := fd.dentry()
- if err := d.inode.setStat(ctx, creds, &opts.Stat); err != nil {
+ if err := d.inode.setStat(ctx, creds, &opts); err != nil {
return err
}
--
cgit v1.2.3