linux-kernel - [PATCH] zram: fix max pool limitation

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <1439299983-8070-2-git-send-email-sergey.senozhatsky@gmail.com>
Date:	Tue, 11 Aug 2015 22:33:03 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: [PATCH] zram: fix max pool limitation

zram_meta_alloc() constructs a pool name for zs_create_pool() call
as
 snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);

However, it defines pool name buffer to be only 8 chars long
(minus trailing zero), which means that we can have only 1000
pool names: zram0 -- zram999.

With CONFIG_ZSMALLOC_STAT enabled an attempt to create a device
zram1000 can fail if device zram100 already exists, because
snprintf() will truncate new pool name to zram100 and pass it
to debugfs_create_dir(), causing:

  debugfs dir <zram100> creation failed
  zram: Error creating memory pool

... and so on (zram101 - zram1010, etc).

Fix it by increasing pool_name buffer size to 11:
-- zram prefix (length 4)
-- int device_id can use up to 10 chars
-- terminating zero byte

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
---
 drivers/block/zram/zram_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index b088ca9..1dec01d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -502,7 +502,7 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize)
 static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
 {
 	size_t num_pages;
-	char pool_name[8];
+	char pool_name[15];
 	struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
 
 	if (!meta)
-- 
2.5.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/