Making 'blk' sector_t (i.e. 64 bit if LBD support is active) fails the 'blk>0' test in the partition block loop if a value of (signed int) -1 is used to mark the end of the partition block list.
This bug was introduced in patch 3 of my prior Amiga partition support fixes series, and spotted by Christian Zigotzky when testing the latest block updates.
Explicitly cast 'blk' to signed int to allow use of -1 to terminate the partition block linked list.
Testing by Christian also exposed another aspect of the old bug fixed in commits fc3d092c6b ("block: fix signed int overflow in Amiga partition support") and b6f3f28f60 ("block: add overflow checks for Amiga partition support"):
Partitons that did overflow the disk size (due to 32 bit int overflow) were not skipped but truncated to the end of the disk. Users who missed the warning message during boot would go on to create a filesystem with a size exceeding the actual partition size. Now that the 32 bit overflow has been corrected, such filesystems may refuse to mount with a 'filesystem exceeds partition size' error. Users should either correct the partition size, or resize the filesystem before attempting to boot a kernel with the RDB fixes in place.
Reported-by: Christian Zigotzky chzigotzky@xenosoft.de Fixes: b6f3f28f60 ("block: add overflow checks for Amiga partition support") Message-ID: 024ce4fa-cc6d-50a2-9aae-3701d0ebf668@xenosoft.de Cc: stable@vger.kernel.org # 6.4 Link: https://lore.kernel.org/r/024ce4fa-cc6d-50a2-9aae-3701d0ebf668@xenosoft.de Signed-off-by: Michael Schmitz schmitzmic@gmail.com Tested-by: Christian Zigotzky chzigotzky@xenosoft.de
--
Changes since v1:
- corrected Fixes: tag - added Tested-by: - reworded commit message to describe filesystem partition size mismatch problem --- block/partitions/amiga.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/partitions/amiga.c b/block/partitions/amiga.c index ed222b9c901b..506921095412 100644 --- a/block/partitions/amiga.c +++ b/block/partitions/amiga.c @@ -90,7 +90,7 @@ 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)) { + for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) { /* 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",