libblkid: rewrite ntfs prober

 - use regular NTFS bios parameters block
 - don't care about mirror cluster location
 - remove unnecessary macros
 - add more checks (based on Linux kernel code)

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libblkid/src/superblocks/ntfs.c b/libblkid/src/superblocks/ntfs.c
index 19dc5b3346058a1a94f8591665ba87fc5a667324..41c6b9cd5fe5e2aea417572b42a0fd66e6b51e48 100644 (file)
--- a/libblkid/src/superblocks/ntfs.c
+++ b/libblkid/src/superblocks/ntfs.c
@@ -13,20 +13,37 @@
 
 #include "superblocks.h"
 
+struct ntfs_bios_parameters {
+       uint16_t        sector_size;    /* Size of a sector in bytes. */
+       uint8_t         sectors_per_cluster;    /* Size of a cluster in sectors. */
+       uint16_t        reserved_sectors;       /* zero */
+       uint8_t         fats;                   /* zero */
+       uint16_t        root_entries;           /* zero */
+       uint16_t        sectors;                /* zero */
+       uint8_t         media_type;             /* 0xf8 = hard disk */
+       uint16_t        sectors_per_fat;        /* zero */
+       uint16_t        sectors_per_track;      /* irrelevant */
+       uint16_t        heads;                  /* irrelevant */
+       uint32_t        hidden_sectors;         /* zero */
+       uint32_t        large_sectors;          /* zero */
+} __attribute__ ((__packed__));
+
 struct ntfs_super_block {
        uint8_t         jump[3];
-       uint8_t         oem_id[8];
-       uint8_t         bios_parameter_block[25];
+       uint8_t         oem_id[8];      /* magic string */
+
+       struct ntfs_bios_parameters     bpb;
+
        uint16_t        unused[2];
        uint64_t        number_of_sectors;
        uint64_t        mft_cluster_location;
        uint64_t        mft_mirror_cluster_location;
-       int8_t          cluster_per_mft_record;
+       int8_t          clusters_per_mft_record;
        uint8_t         reserved1[3];
        int8_t          cluster_per_index_record;
        uint8_t         reserved2[3];
        uint64_t        volume_serial;
-       uint16_t        checksum;
+       uint32_t        checksum;
 } __attribute__((packed));
 
 struct master_file_table_record {
@@ -54,18 +71,21 @@ struct file_attribute {
        uint16_t        value_offset;
 } __attribute__((__packed__));
 
-#define MFT_RECORD_VOLUME                      3
-#define MFT_RECORD_ATTR_VOLUME_NAME            0x60
-#define MFT_RECORD_ATTR_VOLUME_INFO            0x70
-#define MFT_RECORD_ATTR_OBJECT_ID              0x40
-#define MFT_RECORD_ATTR_END                    0xffffffffu
+#define MFT_RECORD_VOLUME      3
+#define NTFS_MAX_CLUSTER_SIZE  (64 * 1024)
+
+enum {
+       MFT_RECORD_ATTR_VOLUME_NAME             = cpu_to_le32(0x60),
+       MFT_RECORD_ATTR_END                     = cpu_to_le32(0xffffffff)
+};
 
 static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
 {
        struct ntfs_super_block *ns;
        struct master_file_table_record *mft;
 
-       unsigned int bytes_per_sector, sectors_per_cluster, mft_record_size, attr_off;
+       uint32_t sectors_per_cluster, mft_record_size, attr_off;
+       uint16_t sector_size;
        uint64_t nr_clusters, off;
        unsigned char *buf_mft;
 
@@ -73,38 +93,69 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
        if (!ns)
                return -1;
 
-       bytes_per_sector = ns->bios_parameter_block[0] +
-               (ns->bios_parameter_block[1]  << 8);
-       sectors_per_cluster = ns->bios_parameter_block[2];
+       /*
+        * Check bios parameters block
+        */
+       sector_size = le16_to_cpu(ns->bpb.sector_size);
+       sectors_per_cluster = ns->bpb.sectors_per_cluster;
 
-       if ((bytes_per_sector < 256) || (sectors_per_cluster == 0))
+       if (sector_size < 256 || sector_size > 4096)
                return 1;
 
-       if (ns->cluster_per_mft_record < 0)
-               mft_record_size = 1 << (0 - ns->cluster_per_mft_record);
-       else
-               mft_record_size = ns->cluster_per_mft_record *
-                       sectors_per_cluster * bytes_per_sector;
-       nr_clusters = le64_to_cpu(ns->number_of_sectors) / sectors_per_cluster;
-
-       if ((le64_to_cpu(ns->mft_cluster_location) > nr_clusters) ||
-           (le64_to_cpu(ns->mft_mirror_cluster_location) > nr_clusters))
+       switch (sectors_per_cluster) {
+       case 1: case 2: case 4: case 8: case 16: case 32: case 64: case 128:
+               break;
+       default:
                return 1;
+       }
 
-       off = le64_to_cpu(ns->mft_mirror_cluster_location) *
-               bytes_per_sector * sectors_per_cluster;
+       if ((uint16_t) le16_to_cpu(ns->bpb.sector_size) *
+                       ns->bpb.sectors_per_cluster > NTFS_MAX_CLUSTER_SIZE)
+               return 1;
 
-       buf_mft = blkid_probe_get_buffer(pr, off, mft_record_size);
-       if (!buf_mft)
+       /* Unused fields must be zero */
+       if (le16_to_cpu(ns->bpb.reserved_sectors)
+           || le16_to_cpu(ns->bpb.root_entries)
+           || le16_to_cpu(ns->bpb.sectors)
+           || le16_to_cpu(ns->bpb.sectors_per_fat)
+           || le32_to_cpu(ns->bpb.large_sectors)
+           || ns->bpb.fats)
                return 1;
 
-       if (memcmp(buf_mft, "FILE", 4))
+       if ((uint8_t) ns->clusters_per_mft_record < 0xe1
+           || (uint8_t) ns->clusters_per_mft_record > 0xf7) {
+
+               switch (ns->clusters_per_mft_record) {
+               case 1: case 2: case 4: case 8: case 16: case 32: case 64:
+                       break;
+               default:
+                       return 1;
+               }
+       }
+
+       if (ns->clusters_per_mft_record > 0)
+               mft_record_size = ns->clusters_per_mft_record *
+                                 sectors_per_cluster * sector_size;
+       else
+               mft_record_size = 1 << (0 - ns->clusters_per_mft_record);
+
+       nr_clusters = le64_to_cpu(ns->number_of_sectors) / sectors_per_cluster;
+
+       if ((le64_to_cpu(ns->mft_cluster_location) > nr_clusters) ||
+           (le64_to_cpu(ns->mft_mirror_cluster_location) > nr_clusters))
                return 1;
 
 
-       off = le64_to_cpu(ns->mft_cluster_location) * bytes_per_sector *
+       off = le64_to_cpu(ns->mft_cluster_location) * sector_size *
                sectors_per_cluster;
 
+       DBG(DEBUG_LOWPROBE, printf("NTFS: sector_size=%d, mft_record_size=%d, "
+                       "sectors_per_cluster=%d, nr_clusters=%ju "
+                       "cluster_offset=%jd\n",
+                       (int) sector_size, mft_record_size,
+                       sectors_per_cluster, nr_clusters,
+                       off));
+
        buf_mft = blkid_probe_get_buffer(pr, off, mft_record_size);
        if (!buf_mft)
                return 1;
@@ -124,10 +175,10 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
        mft = (struct master_file_table_record *) buf_mft;
        attr_off = le16_to_cpu(mft->attrs_offset);
 
-       while (attr_off < mft_record_size) {
+       while (attr_off < mft_record_size &&
+              attr_off <= le32_to_cpu(mft->bytes_allocated)) {
 
-               unsigned int attr_len;
-               unsigned int attr_type;
+               uint32_t attr_len;
                struct file_attribute *attr;
 
                attr = (struct file_attribute *) (buf_mft + attr_off);
@@ -135,11 +186,9 @@ static int probe_ntfs(blkid_probe pr, const struct blkid_idmag *mag)
                if (!attr_len)
                        break;
 
-               attr_type = le32_to_cpu(attr->type);
-               if (attr_type == MFT_RECORD_ATTR_END)
+               if (attr->type == MFT_RECORD_ATTR_END)
                        break;
-
-               if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
+               if (attr->type == MFT_RECORD_ATTR_VOLUME_NAME) {
                        unsigned int val_off = le16_to_cpu(attr->value_offset);
                        unsigned int val_len = le32_to_cpu(attr->value_len);
                        unsigned char *val = ((uint8_t *) attr) + val_off;