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* [PATCH] block: add verifier for cmdline partition
@ 2018-05-03 11:17 Wang YanQing
  2018-05-04  7:07 ` Caizhiyong
  0 siblings, 1 reply; 3+ messages in thread
From: Wang YanQing @ 2018-05-03 11:17 UTC (permalink / raw)
  To: axboe; +Cc: gregkh, pombredanne, tglx, caizhiyong, linux-block, linux-kernel

I meet strange filesystem corruption issue recently, the reason
is there are overlaps partitions in cmdline partition argument.

This patch add verifier for cmdline partition, then if there are
overlaps partitions, cmdline_partition will return error and log
a error message.

Signed-off-by: Wang YanQing <udknight@gmail.com>
---
 block/partitions/cmdline.c | 63 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/block/partitions/cmdline.c b/block/partitions/cmdline.c
index e333583..6754c2a 100644
--- a/block/partitions/cmdline.c
+++ b/block/partitions/cmdline.c
@@ -58,6 +58,62 @@ static int __init cmdline_parts_setup(char *s)
 }
 __setup("blkdevparts=", cmdline_parts_setup);
 
+static bool has_overlaps(sector_t from, sector_t size,
+			 sector_t from2, sector_t size2)
+{
+	sector_t end = from + size;
+	sector_t end2 = from2 + size2;
+
+	if (from >= from2 && from < end2)
+		return true;
+
+	if (end > from2 && end <= end2)
+		return true;
+
+	if (from2 >= from && from2 < end)
+		return true;
+
+	if (end2 > from && end2 <= end)
+		return true;
+
+	return false;
+}
+
+static bool cmdline_parts_verifier(int slot, struct parsed_partitions *state)
+{
+	int i, j = slot;
+	bool ret = true;
+
+	for (; state->parts[slot].has_info; slot++) {
+		for (i = j; state->parts[i].has_info; i++) {
+			if (i == slot)
+				continue;
+
+			if (has_overlaps(state->parts[slot].from,
+					 state->parts[slot].size,
+					 state->parts[i].from,
+					 state->parts[i].size)) {
+				pr_err("Invalid cmdline partition:"
+				       "%s[%llu,%llu] overlaps with "
+				       "%s[%llu,%llu]",
+				       state->parts[slot].info.volname,
+				       (u64)state->parts[slot].from << 9,
+				       (u64)state->parts[slot].size << 9,
+				       state->parts[i].info.volname,
+				       (u64)state->parts[i].from << 9,
+				       (u64)state->parts[i].size << 9);
+				ret = false;
+				break;
+			}
+		}
+
+		if (!ret)
+			break;
+	}
+
+	return ret;
+}
+
 /*
  * Purpose: allocate cmdline partitions.
  * Returns:
@@ -70,6 +126,7 @@ int cmdline_partition(struct parsed_partitions *state)
 	sector_t disk_size;
 	char bdev[BDEVNAME_SIZE];
 	struct cmdline_parts *parts;
+	int ret;
 
 	if (cmdline) {
 		if (bdev_parts)
@@ -93,8 +150,12 @@ int cmdline_partition(struct parsed_partitions *state)
 	disk_size = get_capacity(state->bdev->bd_disk) << 9;
 
 	cmdline_parts_set(parts, disk_size, 1, add_part, (void *)state);
+	if (!cmdline_parts_verifier(1, (void *)state))
+		ret = -1;
+	else
+		ret = 1;
 
 	strlcat(state->pp_buf, "\n", PAGE_SIZE);
 
-	return 1;
+	return ret;
 }
-- 
1.8.5.6.2.g3d8a54e.dirty

^ permalink raw reply	[flat|nested] 3+ messages in thread

* RE: [PATCH] block: add verifier for cmdline partition
  2018-05-03 11:17 [PATCH] block: add verifier for cmdline partition Wang YanQing
@ 2018-05-04  7:07 ` Caizhiyong
  2018-05-04 14:20   ` Jens Axboe
  0 siblings, 1 reply; 3+ messages in thread
From: Caizhiyong @ 2018-05-04  7:07 UTC (permalink / raw)
  To: Wang YanQing, axboe
  Cc: gregkh, pombredanne, tglx, linux-block, linux-kernel, Jiangheng

> -----Original Message-----
> From: Wang YanQing [mailto:udknight@gmail.com]
> Sent: Thursday, May 03, 2018 7:18 PM
> To: axboe@kernel.dk
> Cc: gregkh@linuxfoundation.org; pombredanne@nexb.com;
> tglx@linutronix.de; Caizhiyong <caizhiyong@hisilicon.com>; linux-
> block@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [PATCH] block: add verifier for cmdline partition
> 
> I meet strange filesystem corruption issue recently, the reason
> is there are overlaps partitions in cmdline partition argument.
> 
> This patch add verifier for cmdline partition, then if there are
> overlaps partitions, cmdline_partition will return error and log
> a error message.
> 

Partition overlap was intentionally designed in this cmdline partition.
some time, the cmdline partition save raw data(not filesystem), the overlap makes data  access very convenient.

reference  http://lists.infradead.org/pipermail/linux-mtd/2013-August/048092.html

> Signed-off-by: Wang YanQing <udknight@gmail.com>
> ---
>  block/partitions/cmdline.c | 63
> +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 62 insertions(+), 1 deletion(-)
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] block: add verifier for cmdline partition
  2018-05-04  7:07 ` Caizhiyong
@ 2018-05-04 14:20   ` Jens Axboe
  0 siblings, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2018-05-04 14:20 UTC (permalink / raw)
  To: Caizhiyong, Wang YanQing
  Cc: gregkh, pombredanne, tglx, linux-block, linux-kernel, Jiangheng

On 5/4/18 1:07 AM, Caizhiyong wrote:
>> -----Original Message-----
>> From: Wang YanQing [mailto:udknight@gmail.com]
>> Sent: Thursday, May 03, 2018 7:18 PM
>> To: axboe@kernel.dk
>> Cc: gregkh@linuxfoundation.org; pombredanne@nexb.com;
>> tglx@linutronix.de; Caizhiyong <caizhiyong@hisilicon.com>; linux-
>> block@vger.kernel.org; linux-kernel@vger.kernel.org
>> Subject: [PATCH] block: add verifier for cmdline partition
>>
>> I meet strange filesystem corruption issue recently, the reason
>> is there are overlaps partitions in cmdline partition argument.
>>
>> This patch add verifier for cmdline partition, then if there are
>> overlaps partitions, cmdline_partition will return error and log
>> a error message.
>>
> 
> Partition overlap was intentionally designed in this cmdline partition.
> some time, the cmdline partition save raw data(not filesystem), the overlap makes data  access very convenient.
> 
> reference  http://lists.infradead.org/pipermail/linux-mtd/2013-August/048092.html

Might make sense to warn about it at least, it can be very surprising if
it happens inadvertently.

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2018-05-04 14:20 UTC | newest]

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2018-05-03 11:17 [PATCH] block: add verifier for cmdline partition Wang YanQing
2018-05-04  7:07 ` Caizhiyong
2018-05-04 14:20   ` Jens Axboe

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