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daemon: Read ISO9660 Primary Volume Descriptor directly.

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It turns out we can read the information we need for the isoinfo API
directly from the ISO9660 PVD.  We don't need to use either isoinfo or
xorriso.  This also has the advantages of reducing by 1 the number of
dependencies in the appliance, and reducing potential vulnerability to
a crafted ISO file.

This also fixes timezone calculation for the datetime fields.

Thanks: Thomas Schmitt
Updates: commit efb8a766ca
This commit is contained in:
Richard W.M. Jones
2021-03-31 10:32:52 +01:00
parent efb8a766ca
commit 2f587bbaec
2 changed files with 82 additions and 210 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
appliance/packagelist.in
View File

@@ -26,7 +26,6 @@ ifelse(REDHAT,1,
cryptsetup
cryptsetup-luks dnl old name used before Fedora 17
dhclient
genisoimage
gfs-utils
gfs2-utils
grub
@@ -45,7 +44,6 @@ ifelse(REDHAT,1,
syslinux-extlinux
systemd dnl for /sbin/reboot and udevd
vim-minimal
xorriso dnl alternative for genisoimage
xz
zfs-fuse
)
@@ -57,7 +55,6 @@ dnl old name used in Jessie and earlier
cryptsetup
dash
extlinux
genisoimage
dnl gfs-tools, gfs2-tools have been renamed to gfs2-utils
gfs-tools
gfs2-tools
@@ -85,7 +82,6 @@ dnl iproute has been renamed to iproute2
systemd dnl alternative for /sbin/reboot
ufsutils
vim-tiny
xorriso dnl alternative for genisoimage
xz-utils
zfs-fuse
uuid-runtime
@@ -124,13 +120,11 @@ ifelse(SUSE,1,
cryptsetup
dhcpcd
dhcp-client
genisoimage
glibc-locale
gptfdisk
initviocons
iproute2
iputils
mkisofs
ntfsprogs
ntfs-3g
reiserfs
@@ -164,8 +158,6 @@ ifelse(FRUGALWARE,1,
ifelse(MAGEIA,1,
cryptsetup
chkconfig /* for /etc/init.d */
cdrkit-genisoimage
cdrkit-isotools
dhcp-client
extlinux
gfs2-utils
@@ -190,8 +182,6 @@ ifelse(MAGEIA,1,
ifelse(OPENMANDRIVA,1,
cryptsetup
chkconfig /* for /etc/init.d */
cdrkit-genisoimage
cdrkit-isotools
dhcp-client
extlinux
grub2

282
daemon/isoinfo.ml
View File

@@ -17,157 +17,32 @@
*)
open Printf
open Scanf
open Unix
open Std_utils
open Unix_utils
open Mountable
open Utils
include Structs
type tool = Isoinfo | Xorriso
let tool = ref None
let get_tool () =
match !tool with
| Some t -> t
| None ->
(* Prefer isoinfo because we've been using that tool for longer. *)
if Sys.command "isoinfo -version" = 0 then (
tool := Some Isoinfo;
Isoinfo
)
else if Sys.command "xorriso -version" = 0 then (
tool := Some Xorriso;
Xorriso
)
else
failwith "isoinfo or xorriso not available"
(* Default each int field in the struct to -1 and each string to "". *)
let default_iso = {
iso_system_id = "";
iso_volume_id = "";
iso_volume_space_size = -1_l;
iso_volume_set_size = -1_l;
iso_volume_sequence_number = -1_l;
(* This is almost always true for CDs because of the media itself,
* and is not available from xorriso.
*)
iso_logical_block_size = 2048_l;
iso_volume_set_id = "";
iso_publisher_id = "";
iso_data_preparer_id = "";
iso_application_id = "";
iso_copyright_file_id = "";
iso_abstract_file_id = "";
iso_bibliographic_file_id = "";
iso_volume_creation_t = -1_L;
iso_volume_modification_t = -1_L;
iso_volume_expiration_t = -1_L;
iso_volume_effective_t = -1_L;
}
(* This is always in a fixed format:
* "2012 03 16 11:05:46.00"
* or if the field is not present, then:
* "0000 00 00 00:00:00.00"
(* We treat ISO "strA" and "strD" formats the same way, simply
* discarding any trailing spaces.
*)
let parse_isoinfo_date str =
if str = "0000 00 00 00:00:00.00" ||
str = " : : . " then
-1_L
else (
sscanf str "%04d %02d %02d %02d:%02d:%02d"
(fun tm_year tm_mon tm_mday tm_hour tm_min tm_sec ->
(* Adjust fields. *)
let tm_year = tm_year - 1900 in
let tm_mon = tm_mon - 1 in
let iso_parse_strA str =
let len = String.length str in
let rec loop len =
if len > 0 && str.[len-1] = ' ' then loop (len-1) else len
in
let len = loop len in
String.sub str 0 len
(* Convert to time_t *)
let tm = { tm_sec; tm_min; tm_hour; tm_mday; tm_mon; tm_year;
tm_wday = -1; tm_yday = -1; tm_isdst = false } in
Int64.of_float (fst (Unix.mktime tm))
)
)
let iso_parse_strD = iso_parse_strA
let do_isoinfo dev =
(* --debug is necessary to get additional fields, in particular
* the date & time fields.
*)
let lines = command "isoinfo" ["--debug"; "-d"; "-i"; dev] in
let lines = String.nsplit "\n" lines in
(* These always parse the intX_LSB (little endian) version. *)
let iso_parse_int16 s = s |> int_of_le16 |> Int64.to_int32
let iso_parse_int32 s = s |> int_of_le32 |> Int64.to_int32
let ret = ref default_iso in
List.iter (
fun line ->
let n = String.length line in
if String.is_prefix line "System id: " then
ret := { !ret with iso_system_id = String.sub line 11 (n-11) }
else if String.is_prefix line "Volume id: " then
ret := { !ret with iso_volume_id = String.sub line 11 (n-11) }
else if String.is_prefix line "Volume set id: " then
ret := { !ret with iso_volume_set_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Publisher id: " then
ret := { !ret with iso_publisher_id = String.sub line 14 (n-14) }
else if String.is_prefix line "Data preparer id: " then
ret := { !ret with iso_data_preparer_id = String.sub line 18 (n-18) }
else if String.is_prefix line "Application id: " then
ret := { !ret with iso_application_id = String.sub line 16 (n-16) }
else if String.is_prefix line "Copyright File id: " then
ret := { !ret with iso_copyright_file_id = String.sub line 19 (n-19) }
else if String.is_prefix line "Abstract File id: " then
ret := { !ret with iso_abstract_file_id = String.sub line 18 (n-18) }
else if String.is_prefix line "Bibliographic File id: " then
ret := { !ret with
iso_bibliographic_file_id = String.sub line 23 (n-23) }
else if String.is_prefix line "Volume size is: " then (
let i = Int32.of_string (String.sub line 16 (n-16)) in
ret := { !ret with iso_volume_space_size = i }
)
else if String.is_prefix line "Volume set size is: " then (
let i = Int32.of_string (String.sub line 20 (n-20)) in
ret := { !ret with iso_volume_set_size = i }
)
else if String.is_prefix line "Volume set sequence number is: " then (
let i = Int32.of_string (String.sub line 31 (n-31)) in
ret := { !ret with iso_volume_sequence_number = i }
)
else if String.is_prefix line "Logical block size is: " then (
let i = Int32.of_string (String.sub line 23 (n-23)) in
ret := { !ret with iso_logical_block_size = i }
)
else if String.is_prefix line "Creation Date: " then (
let t = parse_isoinfo_date (String.sub line 19 (n-19)) in
ret := { !ret with iso_volume_creation_t = t }
)
else if String.is_prefix line "Modification Date: " then (
let t = parse_isoinfo_date (String.sub line 19 (n-19)) in
ret := { !ret with iso_volume_modification_t = t }
)
else if String.is_prefix line "Expiration Date: " then (
let t = parse_isoinfo_date (String.sub line 19 (n-19)) in
ret := { !ret with iso_volume_expiration_t = t }
)
else if String.is_prefix line "Effective Date: " then (
let t = parse_isoinfo_date (String.sub line 19 (n-19)) in
ret := { !ret with iso_volume_effective_t = t }
)
) lines;
!ret
(* This is always in a fixed format:
* "2021033012313200"
* or if the field is not present, then:
* "0000000000000000"
* XXX Parse the time zone fields too.
*)
let parse_xorriso_date str =
if str = "0000000000000000" then -1_L
else if String.length str <> 16 then -1_L
(* Parse ISO dec-datetime to a Unix time_t. *)
let iso_parse_datetime str =
if String.sub str 0 16 = "0000000000000000" then -1_L
else (
let tm_year = int_of_string (String.sub str 0 4) in
let tm_mon = int_of_string (String.sub str 4 2) in
@@ -180,69 +55,76 @@ let parse_xorriso_date str =
let tm_year = tm_year - 1900 in
let tm_mon = tm_mon - 1 in
(* Convert to time_t *)
(* Convert to time_t in UTC timezone. *)
let tm = { tm_sec; tm_min; tm_hour; tm_mday; tm_mon; tm_year;
tm_wday = -1; tm_yday = -1; tm_isdst = false } in
Int64.of_float (fst (Unix.mktime tm))
let old_TZ = try Some (getenv "TZ") with Not_found -> None in
putenv "TZ" "UTC";
let r = Int64.of_float (fst (mktime tm)) in
Option.may (putenv "TZ") old_TZ;
(* The final byte is a time zone offset from GMT.
*
* The documentation of this at
* https://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor
* is wrong. See the ECMA 119 documentation for a correct
* description.
*
* For a disk image which we know was created
* in BST (GMT+1), this contains 0x4, ie. 4 * 15 mins ahead.
* We have to subtract this from the gmtime above.
*)
let tz = Char.code str.[16] in
let tz = if tz >= 128 then tz - 256 else tz in
r -^ (Int64.of_int (tz * 15 * 60))
)
let do_xorriso dev =
(* stdio: prefix is to work around a stupidity of xorriso. *)
let lines = command "xorriso" ["-indev"; "stdio:" ^ dev; "-pvd_info"] in
let lines = String.nsplit "\n" lines in
let ret = ref default_iso in
List.iter (
fun line ->
let n = String.length line in
if String.is_prefix line "System Id : " then
ret := { !ret with iso_system_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Volume Id : " then
ret := { !ret with iso_volume_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Volume Set Id: " then
ret := { !ret with iso_volume_set_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Publisher Id : " then
ret := { !ret with iso_publisher_id = String.sub line 15 (n-15) }
else if String.is_prefix line "App Id : " then
ret := { !ret with iso_application_id = String.sub line 15 (n-15) }
else if String.is_prefix line "CopyrightFile: " then
ret := { !ret with iso_copyright_file_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Abstract File: " then
ret := { !ret with iso_abstract_file_id = String.sub line 15 (n-15) }
else if String.is_prefix line "Biblio File : " then
ret := { !ret with
iso_bibliographic_file_id = String.sub line 15 (n-15) }
(* XXX The following fields don't appear to be available
* with xorriso:
* - iso_volume_space_size (only available on stderr)
* - iso_volume_sequence_number
* - iso_logical_block_size
*)
(* XXX xorriso provides a timezone for these fields, but
* we don't use it here.
*)
else if String.is_prefix line "Creation Time: " then (
let t = parse_xorriso_date (String.sub line 15 (n-15)) in
ret := { !ret with iso_volume_creation_t = t }
)
else if String.is_prefix line "Modif. Time : " then (
let t = parse_xorriso_date (String.sub line 15 (n-15)) in
ret := { !ret with iso_volume_modification_t = t }
)
else if String.is_prefix line "Expir. Time : " then (
let t = parse_xorriso_date (String.sub line 15 (n-15)) in
ret := { !ret with iso_volume_expiration_t = t }
)
else if String.is_prefix line "Eff. Time : " then (
let t = parse_xorriso_date (String.sub line 15 (n-15)) in
ret := { !ret with iso_volume_effective_t = t }
)
) lines;
!ret
let isoinfo dev =
match get_tool () with
| Isoinfo -> do_isoinfo dev
| Xorriso -> do_xorriso dev
let r, pvd =
with_openfile dev [O_RDONLY] 0 (
fun fd ->
ignore (lseek fd 32768 SEEK_SET);
let pvd = Bytes.create 2048 in
let r = read fd pvd 0 2048 in
r, Bytes.to_string pvd
) in
let sub = String.sub pvd in
(* Check that it looks like an ISO9660 Primary Volume Descriptor.
* https://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor
*)
if r <> 2048 || pvd.[0] <> '\001' || sub 1 5 <> "CD001" then
failwithf "%s: not an ISO file or CD-ROM" dev;
(* Parse out the PVD fields. *)
let iso_system_id = sub 8 32 |> iso_parse_strA in
let iso_volume_id = sub 40 32 |> iso_parse_strA in
let iso_volume_space_size = sub 80 4 |> iso_parse_int32 in
let iso_volume_set_size = sub 120 2 |> iso_parse_int16 in
let iso_volume_sequence_number = sub 124 2 |> iso_parse_int16 in
let iso_logical_block_size = sub 128 2 |> iso_parse_int16 in
let iso_volume_set_id = sub 190 128 |> iso_parse_strD in
let iso_publisher_id = sub 318 128 |> iso_parse_strA in
let iso_data_preparer_id = sub 446 128 |> iso_parse_strA in
let iso_application_id = sub 574 128 |> iso_parse_strA in
let iso_copyright_file_id = sub 702 38 |> iso_parse_strD in
let iso_abstract_file_id = sub 740 36 |> iso_parse_strD in
let iso_bibliographic_file_id = sub 776 37 |> iso_parse_strD in
let iso_volume_creation_t = sub 813 17 |> iso_parse_datetime in
let iso_volume_modification_t = sub 830 17 |> iso_parse_datetime in
let iso_volume_expiration_t = sub 847 17 |> iso_parse_datetime in
let iso_volume_effective_t = sub 864 17 |> iso_parse_datetime in
(* Return the struct. *)
{
iso_system_id; iso_volume_id; iso_volume_space_size;
iso_volume_set_size; iso_volume_sequence_number;
iso_logical_block_size; iso_volume_set_id; iso_publisher_id;
iso_data_preparer_id; iso_application_id; iso_copyright_file_id;
iso_abstract_file_id; iso_bibliographic_file_id;
iso_volume_creation_t; iso_volume_modification_t;
iso_volume_expiration_t; iso_volume_effective_t;
}
let isoinfo_device = isoinfo