MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
write permission. Depending on the hardware MEMLOCK might even be
write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
is always write-once.
MEMSETBADBLOCK modifies the bad block table.
Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
Signed-off-by: Michael Walle <[email protected]>
---
drivers/mtd/mtdchar.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 57c4a2f0b703..30c8273c1eff 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -643,16 +643,12 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
case MEMGETINFO:
case MEMREADOOB:
case MEMREADOOB64:
- case MEMLOCK:
- case MEMUNLOCK:
case MEMISLOCKED:
case MEMGETOOBSEL:
case MEMGETBADBLOCK:
- case MEMSETBADBLOCK:
case OTPSELECT:
case OTPGETREGIONCOUNT:
case OTPGETREGIONINFO:
- case OTPLOCK:
case ECCGETLAYOUT:
case ECCGETSTATS:
case MTDFILEMODE:
@@ -663,9 +659,13 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
/* "dangerous" commands */
case MEMERASE:
case MEMERASE64:
+ case MEMLOCK:
+ case MEMUNLOCK:
+ case MEMSETBADBLOCK:
case MEMWRITEOOB:
case MEMWRITEOOB64:
case MEMWRITE:
+ case OTPLOCK:
if (!(file->f_mode & FMODE_WRITE))
return -EPERM;
break;
--
2.20.1
On Wed, Mar 03, 2021 at 04:57:35PM +0100, Michael Walle wrote:
> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
> write permission. Depending on the hardware MEMLOCK might even be
> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
> is always write-once.
>
> MEMSETBADBLOCK modifies the bad block table.
>
> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
> Signed-off-by: Michael Walle <[email protected]>
> ---
> drivers/mtd/mtdchar.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
Thanks for auditing the rest of these from my original patch. If this
is ok with userspace tools, it's fine with me, but I don't even have
this hardware to test with :)
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Michael,
----- Ursprüngliche Mail -----
> Von: "Greg Kroah-Hartman" <[email protected]>
> An: "Michael Walle" <[email protected]>
> CC: "linux-mtd" <[email protected]>, "linux-kernel" <[email protected]>, "Miquel Raynal"
> <[email protected]>, "richard" <[email protected]>, "Vignesh Raghavendra" <[email protected]>
> Gesendet: Mittwoch, 3. März 2021 17:08:56
> Betreff: Re: [PATCH] mtd: require write permissions for locking and badblock ioctls
> On Wed, Mar 03, 2021 at 04:57:35PM +0100, Michael Walle wrote:
>> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
>> write permission. Depending on the hardware MEMLOCK might even be
>> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
>> is always write-once.
>>
>> MEMSETBADBLOCK modifies the bad block table.
>>
>> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
>> Signed-off-by: Michael Walle <[email protected]>
>> ---
>> drivers/mtd/mtdchar.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> Thanks for auditing the rest of these from my original patch. If this
> is ok with userspace tools, it's fine with me, but I don't even have
> this hardware to test with :)
That's my fear. Michael, did you verify?
In general you need to be root to open these device files.
So, I don't see a security problem here.
Thanks,
//richard
Am 2021-03-03 17:17, schrieb Richard Weinberger:
> Michael,
>
> ----- Ursprüngliche Mail -----
>> Von: "Greg Kroah-Hartman" <[email protected]>
>> An: "Michael Walle" <[email protected]>
>> CC: "linux-mtd" <[email protected]>, "linux-kernel"
>> <[email protected]>, "Miquel Raynal"
>> <[email protected]>, "richard" <[email protected]>, "Vignesh
>> Raghavendra" <[email protected]>
>> Gesendet: Mittwoch, 3. März 2021 17:08:56
>> Betreff: Re: [PATCH] mtd: require write permissions for locking and
>> badblock ioctls
>
>> On Wed, Mar 03, 2021 at 04:57:35PM +0100, Michael Walle wrote:
>>> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
>>> write permission. Depending on the hardware MEMLOCK might even be
>>> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND.
>>> OTPLOCK
>>> is always write-once.
>>>
>>> MEMSETBADBLOCK modifies the bad block table.
>>>
>>> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for
>>> permissions")
>>> Signed-off-by: Michael Walle <[email protected]>
>>> ---
>>> drivers/mtd/mtdchar.c | 8 ++++----
>>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> Thanks for auditing the rest of these from my original patch. If this
>> is ok with userspace tools, it's fine with me, but I don't even have
>> this hardware to test with :)
>
> That's my fear. Michael, did you verify?
I don't know any tools except the mtd-utils. So no.
> In general you need to be root to open these device files.
> So, I don't see a security problem here.
Then this begs the question, why is this check there in
the first place?
This come up because I was adding a OTPERASE which
was suggested that is was a "dangerous" command. So I
was puzzled why the ones above are considered "safe" ;)
-michael
----- Ursprüngliche Mail -----
>>> Thanks for auditing the rest of these from my original patch. If this
>>> is ok with userspace tools, it's fine with me, but I don't even have
>>> this hardware to test with :)
>>
>> That's my fear. Michael, did you verify?
>
> I don't know any tools except the mtd-utils. So no.
openwrt folks have their own tooling, Anrdoid too.
>> In general you need to be root to open these device files.
>> So, I don't see a security problem here.
>
> Then this begs the question, why is this check there in
> the first place?
I fear historical reasons.
As soon you can open the device node you can do evil things.
> This come up because I was adding a OTPERASE which
> was suggested that is was a "dangerous" command. So I
> was puzzled why the ones above are considered "safe" ;)
:-)
Thanks,
//richard
On 03.03.2021 16:57, Michael Walle wrote:
> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
> write permission. Depending on the hardware MEMLOCK might even be
> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
> is always write-once.
>
> MEMSETBADBLOCK modifies the bad block table.
>
> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
> Signed-off-by: Michael Walle <[email protected]>
Should be fine for OpenWrt tools to my best knowledge (and quick testing).
Acked-by: Rafał Miłecki <[email protected]>
----- Ursprüngliche Mail -----
> Von: "Rafał Miłecki" <[email protected]>
> An: "Michael Walle" <[email protected]>, "linux-mtd" <[email protected]>, "linux-kernel"
> <[email protected]>
> CC: "Miquel Raynal" <[email protected]>, "richard" <[email protected]>, "Vignesh Raghavendra" <[email protected]>,
> "Greg Kroah-Hartman" <[email protected]>
> Gesendet: Montag, 22. März 2021 17:39:41
> Betreff: Re: [PATCH] mtd: require write permissions for locking and badblock ioctls
> On 03.03.2021 16:57, Michael Walle wrote:
>> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
>> write permission. Depending on the hardware MEMLOCK might even be
>> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
>> is always write-once.
>>
>> MEMSETBADBLOCK modifies the bad block table.
>>
>> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
>> Signed-off-by: Michael Walle <[email protected]>
>
> Should be fine for OpenWrt tools to my best knowledge (and quick testing).
>
> Acked-by: Rafał Miłecki <[email protected]>
Nice!
Acked-by: Richard Weinberger <[email protected]>
Thanks,
//richard
On Wed, 2021-03-03 at 15:57:35 UTC, Michael Walle wrote:
> MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
> write permission. Depending on the hardware MEMLOCK might even be
> write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
> is always write-once.
>
> MEMSETBADBLOCK modifies the bad block table.
>
> Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
> Signed-off-by: Michael Walle <[email protected]>
> Reviewed-by: Greg Kroah-Hartman <[email protected]>
> Acked-by: Rafał Miłecki <[email protected]>
> Acked-by: Richard Weinberger <[email protected]>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.
Miquel