| 1 | //go:build linux |
| 2 | |
| 3 | package host |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "os" |
| 8 | "os/user" |
| 9 | "strconv" |
| 10 | |
| 11 | "github.com/carlosframework/platform/internal/hostwrite" |
| 12 | "github.com/carlosframework/platform/internal/safefile" |
| 13 | "golang.org/x/sys/unix" |
| 14 | ) |
| 15 | |
| 16 | func claimStateOwner() (int, int, error) { |
| 17 | u, err := user.Lookup(serviceUser) |
| 18 | if err != nil { |
| 19 | return 0, 0, err |
| 20 | } |
| 21 | uid, err := strconv.Atoi(u.Uid) |
| 22 | if err != nil || uid <= 0 { |
| 23 | return 0, 0, hostwrite.ErrUnavailable |
| 24 | } |
| 25 | gid, err := strconv.Atoi(u.Gid) |
| 26 | return uid, gid, err |
| 27 | } |
| 28 | func claimPrivatePathOwner(path string, uid, gid int, directory bool) error { |
| 29 | var f *os.File |
| 30 | var err error |
| 31 | if directory { |
| 32 | f, err = safefile.OpenDir(path) |
| 33 | } else { |
| 34 | f, err = safefile.OpenFile(path, os.O_RDONLY, 0) |
| 35 | } |
| 36 | if err != nil { |
| 37 | return err |
| 38 | } |
| 39 | defer f.Close() |
| 40 | fd := int(f.Fd()) |
| 41 | var stat unix.Stat_t |
| 42 | if err = unix.Fstat(fd, &stat); err != nil { |
| 43 | return err |
| 44 | } |
| 45 | kind := uint32(unix.S_IFREG) |
| 46 | mode := uint32(0600) |
| 47 | if directory { |
| 48 | kind = unix.S_IFDIR |
| 49 | mode = 0700 |
| 50 | } |
| 51 | if stat.Mode&unix.S_IFMT != kind || (!directory && stat.Nlink != 1) { |
| 52 | return hostwrite.ErrUnavailable |
| 53 | } |
| 54 | if os.Geteuid() == 0 { |
| 55 | if err = unix.Fchown(fd, uid, gid); err != nil { |
| 56 | return err |
| 57 | } |
| 58 | if err = unix.Fchmod(fd, mode); err != nil { |
| 59 | return err |
| 60 | } |
| 61 | } else { |
| 62 | if int(stat.Uid) != uid { |
| 63 | return hostwrite.ErrUnavailable |
| 64 | } |
| 65 | if err = unix.Fchmod(fd, mode); err != nil { |
| 66 | return err |
| 67 | } |
| 68 | } |
| 69 | return nil |
| 70 | } |
| 71 | func prepareClaimStateDirectory(path string) error { |
| 72 | uid, gid, err := claimStateOwner() |
| 73 | if err != nil { |
| 74 | return err |
| 75 | } |
| 76 | if err = safefile.MkdirAll(path, 0700); err != nil { |
| 77 | return err |
| 78 | } |
| 79 | // Retirement journals are root's own and live in /var/lib/carlos-claims. |
| 80 | return claimPrivatePathOwner(path, uid, gid, true) |
| 81 | } |
| 82 | func claimStateDatabaseOwner(path string) error { |
| 83 | uid, gid, err := claimStateOwner() |
| 84 | if err != nil { |
| 85 | return err |
| 86 | } |
| 87 | for _, suffix := range []string{"", "-wal", "-shm"} { |
| 88 | err = claimPrivatePathOwner(path+suffix, uid, gid, false) |
| 89 | if suffix != "" && errors.Is(err, os.ErrNotExist) { |
| 90 | continue |
| 91 | } |
| 92 | if err != nil { |
| 93 | return err |
| 94 | } |
| 95 | } |
| 96 | return nil |
| 97 | } |
| 98 | |
amadan