part_dos: fix crash with big sector size

Apple iPod nanos have sector sizes of 2 or 4 KiB, which crashes U-Boot when it
tries to read the MBR into 512-byte buffer situated on stack. Instead use the
variable length arrays to be safe with any large sector size.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>

disk/part_dos.c

@@ -87,7 +87,7 @@ static int test_block_type(unsigned char *buffer)
 
 int test_part_dos (block_dev_desc_t *dev_desc)
 {
-	unsigned char buffer[DEFAULT_SECTOR_SIZE];
+	unsigned char buffer[dev_desc->blksz];
 
 	if ((dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *) buffer) != 1) ||
 	    (buffer[DOS_PART_MAGIC_OFFSET + 0] != 0x55) ||
@@ -102,7 +102,7 @@ int test_part_dos (block_dev_desc_t *dev_desc)
 static void print_partition_extended (block_dev_desc_t *dev_desc, int ext_part_sector, int relative,
 							   int part_num)
 {
-	unsigned char buffer[DEFAULT_SECTOR_SIZE];
+	unsigned char buffer[dev_desc->blksz];
 	dos_partition_t *pt;
 	int i;
 
@@ -166,7 +166,7 @@ static int get_partition_info_extended (block_dev_desc_t *dev_desc, int ext_part
 				 int relative, int part_num,
 				 int which_part, disk_partition_t *info)
 {
-	unsigned char buffer[DEFAULT_SECTOR_SIZE];
+	unsigned char buffer[dev_desc->blksz];
 	dos_partition_t *pt;
 	int i;
 

disk/part_dos.h

@@ -25,13 +25,6 @@
 #define _DISK_PART_DOS_H
 
 
-#ifdef CONFIG_ISO_PARTITION
-/* Make the buffers bigger if ISO partition support is enabled -- CD-ROMS
-   have 2048 byte blocks */
-#define DEFAULT_SECTOR_SIZE	2048
-#else
-#define DEFAULT_SECTOR_SIZE	512
-#endif
 #define DOS_PART_TBL_OFFSET	0x1be
 #define DOS_PART_MAGIC_OFFSET	0x1fe
 #define DOS_PBR_FSTYPE_OFFSET	0x36