findfs: fix LUKS and FAT detection routines; do not exit if corrupted

 FAT fs makes us try to seek past volume

function                                             old     new   delta
volume_id_get_buffer                                 301     327     +26
volume_id_probe_luks                                  79      82      +3
get_attr_volume_id                                    73      65      -8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 29/-8)              Total: 21 bytes

diff --git a/util-linux/volume_id/fat.c b/util-linux/volume_id/fat.c
index 9ab1cef02114d3eb95a68efd1c252fa46bcda16d..816d69d4c6e909d6490deb09c74b1d9b2fedb473 100644 (file)
--- a/util-linux/volume_id/fat.c
+++ b/util-linux/volume_id/fat.c
@@ -20,8 +20,11 @@
 
 #include "volume_id_internal.h"
 
-#define FAT12_MAX                      0xff5
-#define FAT16_MAX                      0xfff5
+/* linux/msdos_fs.h says: */
+#define FAT12_MAX                      0xff4
+#define FAT16_MAX                      0xfff4
+#define FAT32_MAX                      0x0ffffff6
+
 #define FAT_ATTR_VOLUME_ID             0x08
 #define FAT_ATTR_DIR                   0x10
 #define FAT_ATTR_LONG_NAME             0x0f
@@ -31,9 +34,9 @@
 struct vfat_super_block {
        uint8_t         boot_jump[3];
        uint8_t         sysid[8];
-       uint16_t        sector_size;
+       uint16_t        sector_size_bytes;
        uint8_t         sectors_per_cluster;
-       uint16_t        reserved;
+       uint16_t        reserved_sct;
        uint8_t         fats;
        uint16_t        dir_entries;
        uint16_t        sectors;
@@ -84,32 +87,30 @@ struct vfat_dir_entry {
        uint32_t        size;
 } __attribute__((__packed__));
 
-static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, unsigned count)
+static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, int count)
 {
-       unsigned i;
-
-       for (i = 0; i < count; i++) {
+       for (;--count >= 0; dir++) {
                /* end marker */
-               if (dir[i].name[0] == 0x00) {
+               if (dir->name[0] == 0x00) {
                        dbg("end of dir");
                        break;
                }
 
                /* empty entry */
-               if (dir[i].name[0] == FAT_ENTRY_FREE)
+               if (dir->name[0] == FAT_ENTRY_FREE)
                        continue;
 
                /* long name */
-               if ((dir[i].attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME)
+               if ((dir->attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME)
                        continue;
 
-               if ((dir[i].attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) == FAT_ATTR_VOLUME_ID) {
+               if ((dir->attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) == FAT_ATTR_VOLUME_ID) {
                        /* labels do not have file data */
-                       if (dir[i].cluster_high != 0 || dir[i].cluster_low != 0)
+                       if (dir->cluster_high != 0 || dir->cluster_low != 0)
                                continue;
 
                        dbg("found ATTR_VOLUME_ID id in root dir");
-                       return dir[i].name;
+                       return dir->name;
                }
 
                dbg("skip dir entry");
@@ -118,31 +119,29 @@ static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, unsigned count)
        return NULL;
 }
 
-int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
+int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
 {
        struct vfat_super_block *vs;
        struct vfat_dir_entry *dir;
-       uint16_t sector_size;
+       uint16_t sector_size_bytes;
        uint16_t dir_entries;
        uint32_t sect_count;
-       uint16_t reserved;
-       uint32_t fat_size;
+       uint16_t reserved_sct;
+       uint32_t fat_size_sct;
        uint32_t root_cluster;
-       uint32_t dir_size;
+       uint32_t dir_size_sct;
        uint32_t cluster_count;
-       uint32_t fat_length;
-       uint64_t root_start;
-       uint32_t start_data_sect;
-       uint16_t root_dir_entries;
+       uint64_t root_start_off;
+       uint32_t start_data_sct;
        uint8_t *buf;
        uint32_t buf_size;
        uint8_t *label = NULL;
-       uint32_t next;
+       uint32_t next_cluster;
        int maxloop;
 
-       dbg("probing at offset 0x%llx", (unsigned long long) off);
+       dbg("probing at offset 0x%llx", (unsigned long long) fat_partition_off);
 
-       vs = volume_id_get_buffer(id, off, 0x200);
+       vs = volume_id_get_buffer(id, fat_partition_off, 0x200);
        if (vs == NULL)
                return -1;
 
@@ -196,34 +195,34 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
 
  valid:
        /* sector size check */
-       sector_size = le16_to_cpu(vs->sector_size);
-       if (sector_size != 0x200 && sector_size != 0x400 &&
-           sector_size != 0x800 && sector_size != 0x1000)
+       sector_size_bytes = le16_to_cpu(vs->sector_size_bytes);
+       if (sector_size_bytes != 0x200 && sector_size_bytes != 0x400 &&
+           sector_size_bytes != 0x800 && sector_size_bytes != 0x1000)
                return -1;
 
-       dbg("sector_size 0x%x", sector_size);
+       dbg("sector_size_bytes 0x%x", sector_size_bytes);
        dbg("sectors_per_cluster 0x%x", vs->sectors_per_cluster);
 
-       dir_entries = le16_to_cpu(vs->dir_entries);
-       reserved = le16_to_cpu(vs->reserved);
-       dbg("reserved 0x%x", reserved);
+       reserved_sct = le16_to_cpu(vs->reserved_sct);
+       dbg("reserved_sct 0x%x", reserved_sct);
 
        sect_count = le16_to_cpu(vs->sectors);
        if (sect_count == 0)
                sect_count = le32_to_cpu(vs->total_sect);
        dbg("sect_count 0x%x", sect_count);
 
-       fat_length = le16_to_cpu(vs->fat_length);
-       if (fat_length == 0)
-               fat_length = le32_to_cpu(vs->type.fat32.fat32_length);
-       dbg("fat_length 0x%x", fat_length);
+       fat_size_sct = le16_to_cpu(vs->fat_length);
+       if (fat_size_sct == 0)
+               fat_size_sct = le32_to_cpu(vs->type.fat32.fat32_length);
+       fat_size_sct *= vs->fats;
+       dbg("fat_size_sct 0x%x", fat_size_sct);
 
-       fat_size = fat_length * vs->fats;
-       dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
-                       (sector_size-1)) / sector_size;
-       dbg("dir_size 0x%x", dir_size);
+       dir_entries = le16_to_cpu(vs->dir_entries);
+       dir_size_sct = ((dir_entries * sizeof(struct vfat_dir_entry)) +
+                       (sector_size_bytes-1)) / sector_size_bytes;
+       dbg("dir_size_sct 0x%x", dir_size_sct);
 
-       cluster_count = sect_count - (reserved + fat_size + dir_size);
+       cluster_count = sect_count - (reserved_sct + fat_size_sct + dir_size_sct);
        cluster_count /= vs->sectors_per_cluster;
        dbg("cluster_count 0x%x", cluster_count);
 
@@ -239,21 +238,18 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
                goto fat32;
 
        /* the label may be an attribute in the root directory */
-       root_start = (reserved + fat_size) * sector_size;
-       dbg("root dir start 0x%llx", (unsigned long long) root_start);
-       root_dir_entries = le16_to_cpu(vs->dir_entries);
-       dbg("expected entries 0x%x", root_dir_entries);
+       root_start_off = (reserved_sct + fat_size_sct) * sector_size_bytes;
+       dbg("root dir start 0x%llx", (unsigned long long) root_start_off);
+       dbg("expected entries 0x%x", dir_entries);
 
-       buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
-       buf = volume_id_get_buffer(id, off + root_start, buf_size);
+       buf_size = dir_entries * sizeof(struct vfat_dir_entry);
+       buf = volume_id_get_buffer(id, fat_partition_off + root_start_off, buf_size);
        if (buf == NULL)
                goto found;
 
-       dir = (struct vfat_dir_entry*) buf;
-
-       label = get_attr_volume_id(dir, root_dir_entries);
+       label = get_attr_volume_id((struct vfat_dir_entry*) buf, dir_entries);
 
-       vs = volume_id_get_buffer(id, off, 0x200);
+       vs = volume_id_get_buffer(id, fat_partition_off, 0x200);
        if (vs == NULL)
                return -1;
 
@@ -269,26 +265,25 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
 
  fat32:
        /* FAT32 root dir is a cluster chain like any other directory */
-       buf_size = vs->sectors_per_cluster * sector_size;
+       buf_size = vs->sectors_per_cluster * sector_size_bytes;
        root_cluster = le32_to_cpu(vs->type.fat32.root_cluster);
-       dbg("root dir cluster %u", root_cluster);
-       start_data_sect = reserved + fat_size;
+       start_data_sct = reserved_sct + fat_size_sct;
 
-       next = root_cluster;
+       next_cluster = root_cluster;
        maxloop = 100;
        while (--maxloop) {
-               uint32_t next_sect_off;
+               uint32_t next_off_sct;
                uint64_t next_off;
                uint64_t fat_entry_off;
                int count;
 
-               dbg("next cluster %u", next);
-               next_sect_off = (next - 2) * vs->sectors_per_cluster;
-               next_off = (start_data_sect + next_sect_off) * sector_size;
+               dbg("next_cluster 0x%x", (unsigned)next_cluster);
+               next_off_sct = (next_cluster - 2) * vs->sectors_per_cluster;
+               next_off = (start_data_sct + next_off_sct) * sector_size_bytes;
                dbg("cluster offset 0x%llx", (unsigned long long) next_off);
 
                /* get cluster */
-               buf = volume_id_get_buffer(id, off + next_off, buf_size);
+               buf = volume_id_get_buffer(id, fat_partition_off + next_off, buf_size);
                if (buf == NULL)
                        goto found;
 
@@ -301,20 +296,21 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
                        break;
 
                /* get FAT entry */
-               fat_entry_off = (reserved * sector_size) + (next * sizeof(uint32_t));
-               buf = volume_id_get_buffer(id, off + fat_entry_off, buf_size);
+               fat_entry_off = (reserved_sct * sector_size_bytes) + (next_cluster * sizeof(uint32_t));
+               dbg("fat_entry_off 0x%llx", (unsigned long long)fat_entry_off);
+               buf = volume_id_get_buffer(id, fat_partition_off + fat_entry_off, buf_size);
                if (buf == NULL)
                        goto found;
 
                /* set next cluster */
-               next = le32_to_cpu(*((uint32_t *) buf) & 0x0fffffff);
-               if (next == 0)
+               next_cluster = le32_to_cpu(*(uint32_t*)buf) & 0x0fffffff;
+               if (next_cluster < 2 || next_cluster > FAT32_MAX)
                        break;
        }
        if (maxloop == 0)
                dbg("reached maximum follow count of root cluster chain, give up");
 
-       vs = volume_id_get_buffer(id, off, 0x200);
+       vs = volume_id_get_buffer(id, fat_partition_off, 0x200);
        if (vs == NULL)
                return -1;
 

diff --git a/util-linux/volume_id/luks.c b/util-linux/volume_id/luks.c
index 51dda4e79a2053f07d9a84ebfd4dfb51eb4f1dec..b0f0f5b21a9956a8f5f119df335fdb6006805b17 100644 (file)
--- a/util-linux/volume_id/luks.c
+++ b/util-linux/volume_id/luks.c
@@ -20,20 +20,16 @@
 
 #include "volume_id_internal.h"
 
-#define SECTOR_SHIFT                   9
-#define SECTOR_SIZE                    (1 << SECTOR_SHIFT)
-
-#define LUKS_CIPHERNAME_L              32
-#define LUKS_CIPHERMODE_L              32
-#define LUKS_HASHSPEC_L                        32
-#define LUKS_DIGESTSIZE                        20
-#define LUKS_SALTSIZE                  32
-#define LUKS_NUMKEYS                   8
+#define LUKS_MAGIC_L             6
+#define UUID_STRING_L           40
+#define LUKS_CIPHERNAME_L       32
+#define LUKS_CIPHERMODE_L       32
+#define LUKS_HASHSPEC_L         32
+#define LUKS_DIGESTSIZE         20
+#define LUKS_SALTSIZE           32
+#define LUKS_NUMKEYS             8
 
 static const uint8_t LUKS_MAGIC[] = { 'L','U','K','S', 0xba, 0xbe };
-#define LUKS_MAGIC_L 6
-#define LUKS_PHDR_SIZE (sizeof(struct luks_phdr)/SECTOR_SIZE+1)
-#define UUID_STRING_L 40
 
 struct luks_phdr {
        uint8_t         magic[LUKS_MAGIC_L];
@@ -56,11 +52,39 @@ struct luks_phdr {
        } keyblock[LUKS_NUMKEYS];
 };
 
+enum {
+       EXPECTED_SIZE_luks_phdr = 0
+               + 1 * LUKS_MAGIC_L
+               + 2
+               + 1 * LUKS_CIPHERNAME_L
+               + 1 * LUKS_CIPHERMODE_L
+               + 1 * LUKS_HASHSPEC_L
+               + 4
+               + 4
+               + 1 * LUKS_DIGESTSIZE
+               + 1 * LUKS_SALTSIZE
+               + 4
+               + 1 * UUID_STRING_L
+               + LUKS_NUMKEYS * (0
+                 + 4
+                 + 4
+                 + 1 * LUKS_SALTSIZE
+                 + 4
+                 + 4
+                 )
+};
+
+struct BUG_bad_size_luks_phdr {
+       char BUG_bad_size_luks_phdr[
+               sizeof(struct luks_phdr) == EXPECTED_SIZE_luks_phdr ?
+               1 : -1];
+};
+
 int volume_id_probe_luks(struct volume_id *id, uint64_t off)
 {
        struct luks_phdr *header;
 
-       header = volume_id_get_buffer(id, off, LUKS_PHDR_SIZE);
+       header = volume_id_get_buffer(id, off, sizeof(*header));
        if (header == NULL)
                return -1;
 

diff --git a/util-linux/volume_id/util.c b/util-linux/volume_id/util.c
index 315d75ca6e6842cc2ade90ec8450bd7ef27dd9bf..c4d20ba470245a48f01899813d3d67f642a2f472 100644 (file)
--- a/util-linux/volume_id/util.c
+++ b/util-linux/volume_id/util.c
@@ -181,7 +181,7 @@ set:
                        buf[4], buf[5],
                        buf[6], buf[7],
                        buf[8], buf[9],
-                       buf[10], buf[11], buf[12], buf[13], buf[14],buf[15]);
+                       buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
                break;
        case UUID_DCE_STRING:
                memcpy(id->uuid, buf, count);
@@ -190,6 +190,9 @@ set:
        }
 }
 
+/* Do not use xlseek here. With it, single corrupted filesystem
+ * may result in attempt to seek past device -> exit.
+ * It's better to ignore such fs and continue.  */
 void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 {
        ssize_t buf_len;
@@ -204,7 +207,10 @@ void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
                /* check if we need to read */
                if ((off + len) > id->sbbuf_len) {
                        dbg("read sbbuf len:0x%llx", (unsigned long long) (off + len));
-                       xlseek(id->fd, 0, SEEK_SET);
+                       if (lseek(id->fd, 0, SEEK_SET) != 0) {
+                               dbg("seek(0) failed");
+                               return NULL;
+                       }
                        buf_len = full_read(id->fd, id->sbbuf, off + len);
                        if (buf_len < 0) {
                                dbg("read failed (%s)", strerror(errno));
@@ -234,7 +240,10 @@ void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
        /* check if we need to read */
        if ((off < id->seekbuf_off) || ((off + len) > (id->seekbuf_off + id->seekbuf_len))) {
                dbg("read seekbuf off:0x%llx len:0x%zx", (unsigned long long) off, len);
-               xlseek(id->fd, off, SEEK_SET);
+               if (lseek(id->fd, off, SEEK_SET) != off) {
+                       dbg("seek(0x%llx) failed", (unsigned long long) off);
+                       return NULL;
+               }
                buf_len = full_read(id->fd, id->seekbuf, len);
                if (buf_len < 0) {
                        dbg("read failed (%s)", strerror(errno));