libblkid: udf: Fix parsing of UDF dstring structures

First byte of dstring is OSTA Compression ID and the last byte is length of
recorded bytes (including first byte). Last byte is not a part of recorded
characters, therefore it should not be treated as data to decode.

diff --git a/libblkid/src/superblocks/udf.c b/libblkid/src/superblocks/udf.c
index 602cf408e0421410d20757ebec4d06e32264f60f..832acb1b4e8ed7f3f5b7881d9d3c82ca196d8106 100644 (file)
--- a/libblkid/src/superblocks/udf.c
+++ b/libblkid/src/superblocks/udf.c
@@ -19,13 +19,15 @@
 #include "superblocks.h"
 
 struct dstring128 {
+       uint8_t cid;
+       uint8_t c[126];
        uint8_t clen;
-       uint8_t c[127];
 } __attribute__((packed));
 
 struct dstring32 {
+       uint8_t cid;
+       uint8_t c[30];
        uint8_t clen;
-       uint8_t c[31];
 } __attribute__((packed));
 
 struct volume_descriptor {
@@ -80,15 +82,22 @@ static inline int gen_uuid_from_volset_id(unsigned char uuid[17], struct dstring
 {
        size_t i;
        size_t len;
+       size_t clen;
        size_t nonhexpos;
        unsigned char buf[17];
 
        memset(buf, 0, sizeof(buf));
 
-       if (volset_id->clen == 8)
-               len = blkid_encode_to_utf8(BLKID_ENC_LATIN1, buf, sizeof(buf), volset_id->c, 127);
-       else if (volset_id->clen == 16)
-               len = blkid_encode_to_utf8(BLKID_ENC_UTF16BE, buf, sizeof(buf), volset_id->c, 127);
+       clen = volset_id->clen;
+       if (clen > 0)
+               --clen;
+       if (clen > sizeof(volset_id->c))
+               clen = sizeof(volset_id->c);
+
+       if (volset_id->cid == 8)
+               len = blkid_encode_to_utf8(BLKID_ENC_LATIN1, buf, sizeof(buf), volset_id->c, clen);
+       else if (volset_id->cid == 16)
+               len = blkid_encode_to_utf8(BLKID_ENC_UTF16BE, buf, sizeof(buf), volset_id->c, clen);
        else
                return -1;
 
@@ -215,14 +224,19 @@ real_blksz:
                        break;
                if (type == 1) { /* TAG_ID_PVD */
                        if (!have_volid) {
+                               uint8_t cid = vd->type.primary.ident.cid;
                                uint8_t clen = vd->type.primary.ident.clen;
-                               if (clen == 8)
+                               if (clen > 0)
+                                       --clen;
+                               if (clen > sizeof(vd->type.primary.ident.c))
+                                       clen = sizeof(vd->type.primary.ident.c);
+                               if (cid == 8)
                                        have_volid = !blkid_probe_set_utf8_id_label(pr, "VOLUME_ID",
-                                                       vd->type.primary.ident.c, 31,
+                                                       vd->type.primary.ident.c, clen,
                                                        BLKID_ENC_LATIN1);
-                               else if (clen == 16)
+                               else if (cid == 16)
                                        have_volid = !blkid_probe_set_utf8_id_label(pr, "VOLUME_ID",
-                                                       vd->type.primary.ident.c, 31,
+                                                       vd->type.primary.ident.c, clen,
                                                        BLKID_ENC_UTF16BE);
                        }
                        if (!have_uuid) {
@@ -260,14 +274,19 @@ real_blksz:
                                        have_uuid = !blkid_probe_strncpy_uuid(pr, uuid, sizeof(uuid));
                        }
                        if (!have_volsetid) {
+                               uint8_t cid = vd->type.primary.volset_id.cid;
                                uint8_t clen = vd->type.primary.volset_id.clen;
-                               if (clen == 8)
+                               if (clen > 0)
+                                       --clen;
+                               if (clen > sizeof(vd->type.primary.volset_id.c))
+                                       clen = sizeof(vd->type.primary.volset_id.c);
+                               if (cid == 8)
                                        have_volsetid = !blkid_probe_set_utf8_id_label(pr, "VOLUME_SET_ID",
-                                                       vd->type.primary.volset_id.c, 127,
+                                                       vd->type.primary.volset_id.c, clen,
                                                        BLKID_ENC_LATIN1);
-                               else if (clen == 16)
+                               else if (cid == 16)
                                        have_volsetid = !blkid_probe_set_utf8_id_label(pr, "VOLUME_SET_ID",
-                                                       vd->type.primary.volset_id.c, 127,
+                                                       vd->type.primary.volset_id.c, clen,
                                                        BLKID_ENC_UTF16BE);
                        }
                } else if (type == 6) { /* TAG_ID_LVD */
@@ -298,24 +317,29 @@ real_blksz:
                                 * LABEL also from this field. Program newfs_udf (from UDFclient)
                                 * when formatting disk set this field from user option Disc Name.
                                 */
+                               uint8_t cid = vd->type.logical.logvol_id.cid;
                                uint8_t clen = vd->type.logical.logvol_id.clen;
-                               if (clen == 8) {
+                               if (clen > 0)
+                                       --clen;
+                               if (clen > sizeof(vd->type.logical.logvol_id.c))
+                                       clen = sizeof(vd->type.logical.logvol_id.c);
+                               if (cid == 8) {
                                        if (!have_label)
                                                have_label = !blkid_probe_set_utf8label(pr,
-                                                               vd->type.logical.logvol_id.c, 127,
+                                                               vd->type.logical.logvol_id.c, clen,
                                                                BLKID_ENC_LATIN1);
                                        if (!have_logvolid)
                                                have_logvolid = !blkid_probe_set_utf8_id_label(pr, "LOGICAL_VOLUME_ID",
-                                                               vd->type.logical.logvol_id.c, 127,
+                                                               vd->type.logical.logvol_id.c, clen,
                                                                BLKID_ENC_LATIN1);
-                               } else if (clen == 16) {
+                               } else if (cid == 16) {
                                        if (!have_label)
                                                have_label = !blkid_probe_set_utf8label(pr,
-                                                               vd->type.logical.logvol_id.c,
-                                                               127, BLKID_ENC_UTF16BE);
+                                                               vd->type.logical.logvol_id.c, clen,
+                                                               BLKID_ENC_UTF16BE);
                                        if (!have_logvolid)
                                                have_logvolid = !blkid_probe_set_utf8_id_label(pr, "LOGICAL_VOLUME_ID",
-                                                               vd->type.logical.logvol_id.c, 127,
+                                                               vd->type.logical.logvol_id.c, clen,
                                                                BLKID_ENC_UTF16BE);
                                }
                        }