block: fix signed int overflow in Amiga partition support

The Amiga partition parser module uses signed int for partition sector
address and count, which will overflow for disks larger than 1 TB.

Use sector_t as type for sector address and size to allow using disks
up to 2 TB without LBD support, and disks larger than 2 TB with LBD.

This bug was reported originally in 2012, and the fix was created by
the RDB author, Joanne Dow <jdow@earthlink.net>. A patch had been
discussed and reviewed on linux-m68k at that time but never officially
submitted. This patch differs from Joanne's patch only in its use of
sector_t instead of unsigned int. No checking for overflows is done
(see patch 3 of this series for that).

Reported-by: Martin Steigerwald <Martin@lichtvoll.de>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=43511
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Message-ID: <201206192146.09327.Martin@lichtvoll.de>
Cc: <stable@vger.kernel.org> # 5.2
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Martin Steigerwald <Martin@lichtvoll.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230620201725.7020-2-schmitzmic@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c
index 5c8624e26a54c12823237581cc1b01a6ed740e95..85c5c79aae4819e9dceefe6a014241248594ff0a 100644 (file)
--- a/block/partitions/amiga.c
+++ b/block/partitions/amiga.c
@@ -31,7 +31,8 @@ int amiga_partition(struct parsed_partitions *state)
        unsigned char *data;
        struct RigidDiskBlock *rdb;
        struct PartitionBlock *pb;
-       int start_sect, nr_sects, blk, part, res = 0;
+       sector_t start_sect, nr_sects;
+       int blk, part, res = 0;
        int blksize = 1;        /* Multiplier for disk block size */
        int slot = 1;
 
@@ -96,14 +97,14 @@ int amiga_partition(struct parsed_partitions *state)
 
                /* Tell Kernel about it */
 
-               nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
-                           be32_to_cpu(pb->pb_Environment[9])) *
+               nr_sects = ((sector_t)be32_to_cpu(pb->pb_Environment[10]) + 1 -
+                          be32_to_cpu(pb->pb_Environment[9])) *
                           be32_to_cpu(pb->pb_Environment[3]) *
                           be32_to_cpu(pb->pb_Environment[5]) *
                           blksize;
                if (!nr_sects)
                        continue;
-               start_sect = be32_to_cpu(pb->pb_Environment[9]) *
+               start_sect = (sector_t)be32_to_cpu(pb->pb_Environment[9]) *
                             be32_to_cpu(pb->pb_Environment[3]) *
                             be32_to_cpu(pb->pb_Environment[5]) *
                             blksize;