diff options
Diffstat (limited to 'pkg/sentry/fs/dev/dev.go')
| -rw-r--r-- | pkg/sentry/fs/dev/dev.go | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/pkg/sentry/fs/dev/dev.go b/pkg/sentry/fs/dev/dev.go index e1eaa08cb..fbc750a71 100644 --- a/pkg/sentry/fs/dev/dev.go +++ b/pkg/sentry/fs/dev/dev.go @@ -27,6 +27,19 @@ import ( "gvisor.googlesource.com/gvisor/pkg/sentry/usermem" ) +// Memory device numbers are from Linux's drivers/char/mem.c +const ( + // Mem device major. + memDevMajor uint16 = 1 + + // Mem device minors. + nullDevMinor uint32 = 3 + zeroDevMinor uint32 = 5 + fullDevMinor uint32 = 7 + randomDevMinor uint32 = 8 + urandomDevMinor uint32 = 9 +) + func newCharacterDevice(iops fs.InodeOperations, msrc *fs.MountSource) *fs.Inode { return fs.NewInode(iops, msrc, fs.StableAttr{ DeviceID: devDevice.DeviceID(), @@ -36,6 +49,17 @@ func newCharacterDevice(iops fs.InodeOperations, msrc *fs.MountSource) *fs.Inode }) } +func newMemDevice(iops fs.InodeOperations, msrc *fs.MountSource, minor uint32) *fs.Inode { + return fs.NewInode(iops, msrc, fs.StableAttr{ + DeviceID: devDevice.DeviceID(), + InodeID: devDevice.NextIno(), + BlockSize: usermem.PageSize, + Type: fs.CharacterDevice, + DeviceFileMajor: memDevMajor, + DeviceFileMinor: minor, + }) +} + func newDirectory(ctx context.Context, msrc *fs.MountSource) *fs.Inode { iops := ramfs.NewDir(ctx, nil, fs.RootOwner, fs.FilePermsFromMode(0555)) return fs.NewInode(iops, msrc, fs.StableAttr{ @@ -64,17 +88,17 @@ func New(ctx context.Context, msrc *fs.MountSource, binderEnabled bool, ashmemEn "stdout": newSymlink(ctx, "/proc/self/fd/1", msrc), "stderr": newSymlink(ctx, "/proc/self/fd/2", msrc), - "null": newCharacterDevice(newNullDevice(ctx, fs.RootOwner, 0666), msrc), - "zero": newCharacterDevice(newZeroDevice(ctx, fs.RootOwner, 0666), msrc), - "full": newCharacterDevice(newFullDevice(ctx, fs.RootOwner, 0666), msrc), + "null": newMemDevice(newNullDevice(ctx, fs.RootOwner, 0666), msrc, nullDevMinor), + "zero": newMemDevice(newZeroDevice(ctx, fs.RootOwner, 0666), msrc, zeroDevMinor), + "full": newMemDevice(newFullDevice(ctx, fs.RootOwner, 0666), msrc, fullDevMinor), // This is not as good as /dev/random in linux because go // runtime uses sys_random and /dev/urandom internally. // According to 'man 4 random', this will be sufficient unless // application uses this to generate long-lived GPG/SSL/SSH // keys. - "random": newCharacterDevice(newRandomDevice(ctx, fs.RootOwner, 0444), msrc), - "urandom": newCharacterDevice(newRandomDevice(ctx, fs.RootOwner, 0444), msrc), + "random": newMemDevice(newRandomDevice(ctx, fs.RootOwner, 0444), msrc, randomDevMinor), + "urandom": newMemDevice(newRandomDevice(ctx, fs.RootOwner, 0444), msrc, urandomDevMinor), "shm": tmpfs.NewDir(ctx, nil, fs.RootOwner, fs.FilePermsFromMode(0777), msrc), |