Re: FAILED: patch "[PATCH] block: add overflow checks for Amiga partition support" failed to apply to 5.10-stable tree

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Greg,

Am 12.07.2023 um 08:45 schrieb Michael Schmitz:
> Hi Greg,
>
> this patch was part of a series of three patches
> (fc3d092c6bb48d5865fec15ed5b333c12f36288c,
> 95a55437dc49fb3342c82e61f5472a71c63d9ed0,
> b6f3f28f604ba3de4724ad82bea6adb1300c0b5f). The first in that series must
> also be cherry-picked in order for the third one to apply cleanly.
>
> You appear to have applied fc3d092c6bb48d5865fec15ed5b333c12f36288c to
> 5.4 and 5.10 now, so I'd expect re-applying
> b6f3f28f604ba3de4724ad82bea6adb1300c0b5f would work OK

Apologies for insinuating you'd forgotten to apply the prerequisite 
patches. I evidently messed up the stable prerequisite tag for that patch.

I've corrected the merge conflicts (along with a few compile errors) and 
tested on ARAnyM with the same RDB disk image I'd used to test the 
original series.

Now one question remains:

>
> Please note that after these have all been applied, we still need
> 7eb1e47696aa231b1a567846bbe3a1e1befe1854 ("block/partition: fix
> signedness issue for Amiga partitions") which is a bugfix for
> b6f3f28f604ba3de4724ad82bea6adb1300c0b5f.

The bugfix to b6f3f28f604ba3de4724ad82bea6adb1300c0b5f is still needed 
but 7eb1e47696aa231b1a567846bbe3a1e1befe1854 wasn't available in 5.4 nor 
5.10.

Would you prefer to have this bugfix folded into the resubmitted patches 
for 5.4 and 5.10, or pick it up from linux-block separate?

Cheers,

	Michael


> Thanks!
>
> Cheers,
>
>     Michael
>
>
> On 12/07/23 08:30, gregkh@linuxfoundation.org wrote:
>> The patch below does not apply to the 5.10-stable tree.
>> If someone wants it applied there, or to any other stable or longterm
>> tree, then please email the backport, including the original git commit
>> id to <stable@vger.kernel.org>.
>>
>> To reproduce the conflict and resubmit, you may use the following
>> commands:
>>
>> git fetch
>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/
>> linux-5.10.y
>> git checkout FETCH_HEAD
>> git cherry-pick -x b6f3f28f604ba3de4724ad82bea6adb1300c0b5f
>> # <resolve conflicts, build, test, etc.>
>> git commit -s
>> git send-email --to '<stable@vger.kernel.org>' --in-reply-to
>> '2023071116-umbrella-fog-a65f@gregkh' --subject-prefix 'PATCH 5.10.y'
>> HEAD^..
>>
>> Possible dependencies:
>>
>>
>>
>> thanks,
>>
>> greg k-h
>>
>> ------------------ original commit in Linus's tree ------------------
>>
>>  From b6f3f28f604ba3de4724ad82bea6adb1300c0b5f Mon Sep 17 00:00:00 2001
>> From: Michael Schmitz <schmitzmic@gmail.com>
>> Date: Wed, 21 Jun 2023 08:17:25 +1200
>> Subject: [PATCH] block: add overflow checks for 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 u64 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. The RBD
>> format allows to specify disk sizes up to 2^128 bytes (though native
>> OS limitations reduce this somewhat, to max 2^68 bytes), so check for
>> u64 overflow carefully to protect against overflowing sector_t.
>>
>> Bail out if sector addresses overflow 32 bits on kernels without LBD
>> support.
>>
>> 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 (now resubmitted as patch 1 in this series).
>> This patch adds additional error checking and warning messages.
>>
>> 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>
>> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
>> Reviewed-by: Christoph Hellwig <hch@infradead.org>
>> Link:
>> https://lore.kernel.org/r/20230620201725.7020-4-schmitzmic@gmail.com
>> Signed-off-by: Jens Axboe <axboe@kernel.dk>
>>
>> diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c
>> index 85c5c79aae48..ed222b9c901b 100644
>> --- a/block/partitions/amiga.c
>> +++ b/block/partitions/amiga.c
>> @@ -11,10 +11,18 @@
>>   #define pr_fmt(fmt) fmt
>>     #include <linux/types.h>
>> +#include <linux/mm_types.h>
>> +#include <linux/overflow.h>
>>   #include <linux/affs_hardblocks.h>
>>     #include "check.h"
>>   +/* magic offsets in partition DosEnvVec */
>> +#define NR_HD    3
>> +#define NR_SECT    5
>> +#define LO_CYL    9
>> +#define HI_CYL    10
>> +
>>   static __inline__ u32
>>   checksum_block(__be32 *m, int size)
>>   {
>> @@ -31,9 +39,12 @@ int amiga_partition(struct parsed_partitions *state)
>>       unsigned char *data;
>>       struct RigidDiskBlock *rdb;
>>       struct PartitionBlock *pb;
>> -    sector_t start_sect, nr_sects;
>> -    int blk, part, res = 0;
>> -    int blksize = 1;    /* Multiplier for disk block size */
>> +    u64 start_sect, nr_sects;
>> +    sector_t blk, end_sect;
>> +    u32 cylblk;        /* rdb_CylBlocks = nr_heads*sect_per_track */
>> +    u32 nr_hd, nr_sect, lo_cyl, hi_cyl;
>> +    int part, res = 0;
>> +    unsigned int blksize = 1;    /* Multiplier for disk block size */
>>       int slot = 1;
>>         for (blk = 0; ; blk++, put_dev_sector(sect)) {
>> @@ -41,7 +52,7 @@ int amiga_partition(struct parsed_partitions *state)
>>               goto rdb_done;
>>           data = read_part_sector(state, blk, &sect);
>>           if (!data) {
>> -            pr_err("Dev %s: unable to read RDB block %d\n",
>> +            pr_err("Dev %s: unable to read RDB block %llu\n",
>>                      state->disk->disk_name, blk);
>>               res = -1;
>>               goto rdb_done;
>> @@ -58,12 +69,12 @@ int amiga_partition(struct parsed_partitions *state)
>>           *(__be32 *)(data+0xdc) = 0;
>>           if (checksum_block((__be32 *)data,
>>                   be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
>> -            pr_err("Trashed word at 0xd0 in block %d ignored in
>> checksum calculation\n",
>> +            pr_err("Trashed word at 0xd0 in block %llu ignored in
>> checksum calculation\n",
>>                      blk);
>>               break;
>>           }
>>   -        pr_err("Dev %s: RDB in block %d has bad checksum\n",
>> +        pr_err("Dev %s: RDB in block %llu has bad checksum\n",
>>                  state->disk->disk_name, blk);
>>       }
>>   @@ -80,10 +91,15 @@ int amiga_partition(struct parsed_partitions
>> *state)
>>       blk = be32_to_cpu(rdb->rdb_PartitionList);
>>       put_dev_sector(sect);
>>       for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
>> -        blk *= blksize;    /* Read in terms partition table
>> understands */
>> +        /* Read in terms partition table understands */
>> +        if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {
>> +            pr_err("Dev %s: overflow calculating partition block
>> %llu! Skipping partitions %u and beyond\n",
>> +                state->disk->disk_name, blk, part);
>> +            break;
>> +        }
>>           data = read_part_sector(state, blk, &sect);
>>           if (!data) {
>> -            pr_err("Dev %s: unable to read partition block %d\n",
>> +            pr_err("Dev %s: unable to read partition block %llu\n",
>>                      state->disk->disk_name, blk);
>>               res = -1;
>>               goto rdb_done;
>> @@ -95,19 +111,70 @@ int amiga_partition(struct parsed_partitions *state)
>>           if (checksum_block((__be32 *)pb,
>> be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
>>               continue;
>>   -        /* Tell Kernel about it */
>> +        /* RDB gives us more than enough rope to hang ourselves with,
>> +         * many times over (2^128 bytes if all fields max out).
>> +         * Some careful checks are in order, so check for potential
>> +         * overflows.
>> +         * We are multiplying four 32 bit numbers to one sector_t!
>> +         */
>> +
>> +        nr_hd   = be32_to_cpu(pb->pb_Environment[NR_HD]);
>> +        nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]);
>> +
>> +        /* CylBlocks is total number of blocks per cylinder */
>> +        if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) {
>> +            pr_err("Dev %s: heads*sects %u overflows u32, skipping
>> partition!\n",
>> +                state->disk->disk_name, cylblk);
>> +            continue;
>> +        }
>> +
>> +        /* check for consistency with RDB defined CylBlocks */
>> +        if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) {
>> +            pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n",
>> +                state->disk->disk_name, cylblk,
>> +                be32_to_cpu(rdb->rdb_CylBlocks));
>> +        }
>> +
>> +        /* RDB allows for variable logical block size -
>> +         * normalize to 512 byte blocks and check result.
>> +         */
>> +
>> +        if (check_mul_overflow(cylblk, blksize, &cylblk)) {
>> +            pr_err("Dev %s: partition %u bytes per cyl. overflows
>> u32, skipping partition!\n",
>> +                state->disk->disk_name, part);
>> +            continue;
>> +        }
>> +
>> +        /* Calculate partition start and end. Limit of 32 bit on cylblk
>> +         * guarantees no overflow occurs if LBD support is enabled.
>> +         */
>> +
>> +        lo_cyl = be32_to_cpu(pb->pb_Environment[LO_CYL]);
>> +        start_sect = ((u64) lo_cyl * cylblk);
>> +
>> +        hi_cyl = be32_to_cpu(pb->pb_Environment[HI_CYL]);
>> +        nr_sects = (((u64) hi_cyl - lo_cyl + 1) * cylblk);
>>   -        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 = (sector_t)be32_to_cpu(pb->pb_Environment[9]) *
>> -                 be32_to_cpu(pb->pb_Environment[3]) *
>> -                 be32_to_cpu(pb->pb_Environment[5]) *
>> -                 blksize;
>> +
>> +        /* Warn user if partition end overflows u32 (AmigaDOS limit) */
>> +
>> +        if ((start_sect + nr_sects) > UINT_MAX) {
>> +            pr_warn("Dev %s: partition %u (%llu-%llu) needs 64 bit
>> device support!\n",
>> +                state->disk->disk_name, part,
>> +                start_sect, start_sect + nr_sects);
>> +        }
>> +
>> +        if (check_add_overflow(start_sect, nr_sects, &end_sect)) {
>> +            pr_err("Dev %s: partition %u (%llu-%llu) needs LBD device
>> support, skipping partition!\n",
>> +                state->disk->disk_name, part,
>> +                start_sect, end_sect);
>> +            continue;
>> +        }
>> +
>> +        /* Tell Kernel about it */
>> +
>>           put_partition(state,slot++,start_sect,nr_sects);
>>           {
>>               /* Be even more informative to aid mounting */
>>