diff options
| author | Jamie Liu <jamieliu@google.com> | 2021-09-16 12:10:03 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-09-16 12:12:59 -0700 |
| commit | 51b96514cd9397870b39506e3693017a355319dd (patch) | |
| tree | 46f465ed03e12efdff1625886604558968d94f56 /pkg/sentry/fs/file_overlay.go | |
| parent | 282a4dd52b337dccfb578e9d32dd1005c864dd8d (diff) | |
Limit most file mmaps to the range of an int64.
In the general case, files may have offsets between MaxInt64 and MaxUint64; in
Linux pgoff is consistently represented by an unsigned long, and in gVisor the
offset types in memmap.MappableRange are uint64. However, regular file mmap is
constrained to int64 offsets (on 64-bit systems) by
mm/mmap.c:file_mmap_size_max() => MAX_LFS_FILESIZE == LLONG_MAX.
As a related fix, check for chunkStart overflow in fsutil.HostFileMapper; chunk
offsets are uint64s, but as noted above some file types may use uint64 offsets
beyond MaxInt64.
Reported-by: syzbot+71342a1585aed97ed9f7@syzkaller.appspotmail.com
PiperOrigin-RevId: 397136751
Diffstat (limited to 'pkg/sentry/fs/file_overlay.go')
| -rw-r--r-- | pkg/sentry/fs/file_overlay.go | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go index 031cd33ce..a27dd0b9a 100644 --- a/pkg/sentry/fs/file_overlay.go +++ b/pkg/sentry/fs/file_overlay.go @@ -16,6 +16,7 @@ package fs import ( "io" + "math" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/errors/linuxerr" @@ -360,10 +361,13 @@ func (*overlayFileOperations) ConfigureMMap(ctx context.Context, file *File, opt return linuxerr.ENODEV } - // FIXME(jamieliu): This is a copy/paste of fsutil.GenericConfigureMMap, - // which we can't use because the overlay implementation is in package fs, - // so depending on fs/fsutil would create a circular dependency. Move - // overlay to fs/overlay. + // TODO(gvisor.dev/issue/1624): This is a copy/paste of + // fsutil.GenericConfigureMMap, which we can't use because the overlay + // implementation is in package fs, so depending on fs/fsutil would create + // a circular dependency. VFS2 overlay doesn't have this issue. + if opts.Offset+opts.Length > math.MaxInt64 { + return linuxerr.EOVERFLOW + } opts.Mappable = o opts.MappingIdentity = file file.IncRef() |