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libvolume_id: fat - check for signature at end of sector

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Kay Sievers
2006-05-13 18:38:03 +02:00
parent acc8322f1f
commit 2bac6c64aa
3 changed files with 37 additions and 11 deletions
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extras/volume_id/lib/Makefile
+1 -1
View File
@@ -13,7 +13,7 @@ INSTALL_DATA = ${INSTALL} -m 644
INSTALL_LIB = ${INSTALL} -m 755
SHLIB_CUR = 0
SHLIB_REV = 63
SHLIB_REV = 64
SHLIB_AGE = 0
SHLIB = libvolume_id.so.$(SHLIB_CUR).$(SHLIB_REV).$(SHLIB_AGE)
extras/volume_id/lib/fat.c
+36 -9
View File
@@ -63,7 +63,7 @@ struct vfat_super_block {
uint16_t flags;
uint8_t version[2];
uint32_t root_cluster;
uint16_t insfo_sector;
uint16_t fsinfo_sector;
uint16_t backup_boot;
uint16_t reserved2[6];
uint8_t unknown[3];
@@ -76,6 +76,15 @@ struct vfat_super_block {
} PACKED type;
} PACKED;
struct fat32_fsinfo {
uint8_t signature1[4];
uint32_t reserved1[120];
uint8_t signature2[4];
uint32_t free_clusters;
uint32_t next_cluster;
uint32_t reserved2[4];
} PACKED;
struct vfat_dir_entry {
uint8_t name[11];
uint8_t attr;
@@ -128,6 +137,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
{
struct vfat_super_block *vs;
struct vfat_dir_entry *dir;
struct fat32_fsinfo *fsinfo;
uint16_t sector_size;
uint16_t dir_entries;
uint32_t sect_count;
@@ -141,6 +151,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
uint64_t root_start;
uint32_t start_data_sect;
uint16_t root_dir_entries;
uint16_t fsinfo_sect;
uint8_t *buf;
uint32_t buf_size;
uint8_t *label = NULL;
@@ -149,16 +160,19 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
info("probing at offset 0x%llx", (unsigned long long) off);
vs = (struct vfat_super_block *) volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
buf = volume_id_get_buffer(id, off, 0x400);
if (buf == NULL)
return -1;
/* believe only that's fat, don't trust the version
* the cluster_count will tell us
*/
/* check signature */
if (buf[510] != 0x55 || buf[511] != 0xaa)
return -1;
vs = (struct vfat_super_block *) buf;
if (memcmp(vs->sysid, "NTFS", 4) == 0)
return -1;
/* believe only that's fat, don't trust the version */
if (memcmp(vs->type.fat32.magic, "MSWIN", 5) == 0)
goto magic;
@@ -174,9 +188,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
if (memcmp(vs->type.fat.magic, "FAT12 ", 8) == 0)
goto magic;
/* some old floppies don't have a magic, so we expect the boot code to match */
/* boot jump address check */
/* some old floppies don't have a magic, expect the boot jump address to match */
if ((vs->boot_jump[0] != 0xeb || vs->boot_jump[2] != 0x90) &&
vs->boot_jump[0] != 0xe9)
return -1;
@@ -280,6 +292,21 @@ magic:
goto found;
fat32:
/* FAT32 should have a valid signature in the fsinfo block */
fsinfo_sect = le16_to_cpu(vs->type.fat32.fsinfo_sector);
buf = volume_id_get_buffer(id, off + (fsinfo_sect * sector_size), 0x200);
if (buf == NULL)
return -1;
fsinfo = (struct fat32_fsinfo *) buf;
if (memcmp(fsinfo->signature1, "\x52\x52\x61\x41", 4) != 0)
return -1;
if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0)
return -1 ;
vs = (struct vfat_super_block *) volume_id_get_buffer(id, off, 0x200);
if (vs == NULL)
return -1;
strcpy(id->type_version, "FAT32");
/* FAT32 root dir is a cluster chain like any other directory */
extras/volume_id/lib/volume_id.c
-1
View File
@@ -99,7 +99,6 @@ int volume_id_probe_filesystem(struct volume_id *id, uint64_t off, uint64_t size
if (volume_id_probe_luks(id, off) == 0)
goto found;
/* signature in the first block, only small buffer needed */
if (volume_id_probe_vfat(id, off) == 0)
goto found;