linux-kernel - [PATCH v2] fs: guard_bio_eod() needs to consider partitions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20171024172148.12397-1-gedwards@ddn.com>
Date:   Tue, 24 Oct 2017 11:21:48 -0600
From:   Greg Edwards <gedwards@....com>
To:     <linux-fsdevel@...r.kernel.org>
CC:     Christoph Hellwig <hch@....de>, Al Viro <viro@...iv.linux.org.uk>,
        "Jens Axboe" <axboe@...nel.dk>, <linux-kernel@...r.kernel.org>,
        Greg Edwards <gedwards@....com>
Subject: [PATCH v2] fs: guard_bio_eod() needs to consider partitions

guard_bio_eod() needs to look at the partition capacity, not just the
capacity of the whole device, when determining if truncation is
necessary.

[   60.268688] attempt to access beyond end of device
[   60.268690] unknown-block(9,1): rw=0, want=67103509, limit=67103506
[   60.268693] buffer_io_error: 2 callbacks suppressed
[   60.268696] Buffer I/O error on dev md1p7, logical block 4524305, async page read

Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and partitions index")
Signed-off-by: Greg Edwards <gedwards@....com>
---
Changes from v1:
  * use __disk_get_part instead of disk_get_part, similar to what
    blk_partition_remap does

 fs/buffer.c           | 10 +++++++++-
 include/linux/genhd.h |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 170df856bdb9..b96f3b98a6ef 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3055,8 +3055,16 @@ void guard_bio_eod(int op, struct bio *bio)
 	sector_t maxsector;
 	struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
 	unsigned truncated_bytes;
+	struct hd_struct *part;
+
+	rcu_read_lock();
+	part = __disk_get_part(bio->bi_disk, bio->bi_partno);
+	if (part)
+		maxsector = part_nr_sects_read(part);
+	else
+		maxsector = get_capacity(bio->bi_disk);
+	rcu_read_unlock();
 
-	maxsector = get_capacity(bio->bi_disk);
 	if (!maxsector)
 		return;
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index ea652bfcd675..cb8c5fd74b71 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -242,6 +242,7 @@ static inline dev_t part_devt(struct hd_struct *part)
 	return part_to_dev(part)->devt;
 }
 
+extern struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
 extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
 
 static inline void disk_put_part(struct hd_struct *part)
-- 
2.13.6