* [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
@ 2024-01-09 14:51 Rand Deeb
2024-01-10 8:43 ` Tali Perry
0 siblings, 1 reply; 6+ messages in thread
From: Rand Deeb @ 2024-01-09 14:51 UTC (permalink / raw)
To: Avi Fishman, Tomer Maimon, Tali Perry, Patrick Venture,
Nancy Yuen, Benjamin Fair, openbmc, linux-i2c, linux-kernel
Cc: deeb.rand, lvc-project, voskresenski.stanislav, Rand Deeb
In the npcm_i2c_reg_slave function, a potential NULL pointer dereference
issue occurs when 'client' is NULL. This patch adds a proper NULL check for
'client' at the beginning of the function to prevent undefined behavior.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
---
drivers/i2c/busses/i2c-npcm7xx.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index c1b679737240..cfabfb50211d 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1243,13 +1243,14 @@ static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus)
static int npcm_i2c_reg_slave(struct i2c_client *client)
{
unsigned long lock_flags;
- struct npcm_i2c *bus = i2c_get_adapdata(client->adapter);
-
- bus->slave = client;
+ struct npcm_i2c *bus;
- if (!bus->slave)
+ if (!client)
return -EINVAL;
+ bus = i2c_get_adapdata(client->adapter);
+ bus->slave = client;
+
if (client->flags & I2C_CLIENT_TEN)
return -EAFNOSUPPORT;
--
2.34.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
2024-01-09 14:51 [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave Rand Deeb
@ 2024-01-10 8:43 ` Tali Perry
2024-01-10 9:23 ` Re: [lvc-project] " Fedor Pchelkin
0 siblings, 1 reply; 6+ messages in thread
From: Tali Perry @ 2024-01-10 8:43 UTC (permalink / raw)
To: Rand Deeb
Cc: Avi Fishman, Tomer Maimon, Patrick Venture, Nancy Yuen,
Benjamin Fair, openbmc, linux-i2c, linux-kernel, deeb.rand,
lvc-project, voskresenski.stanislav
On Tue, Jan 9, 2024 at 4:52 PM Rand Deeb <rand.sec96@gmail.com> wrote:
>
> In the npcm_i2c_reg_slave function, a potential NULL pointer dereference
> issue occurs when 'client' is NULL. This patch adds a proper NULL check for
> 'client' at the beginning of the function to prevent undefined behavior.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
> ---
> drivers/i2c/busses/i2c-npcm7xx.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index c1b679737240..cfabfb50211d 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1243,13 +1243,14 @@ static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus)
> static int npcm_i2c_reg_slave(struct i2c_client *client)
> {
> unsigned long lock_flags;
> - struct npcm_i2c *bus = i2c_get_adapdata(client->adapter);
> -
> - bus->slave = client;
> + struct npcm_i2c *bus;
>
> - if (!bus->slave)
> + if (!client)
> return -EINVAL;
>
> + bus = i2c_get_adapdata(client->adapter);
> + bus->slave = client;
> +
> if (client->flags & I2C_CLIENT_TEN)
> return -EAFNOSUPPORT;
>
> --
> 2.34.1
>
Thanks for the patch!
Reviewed-by:tali.perry1@gmail.com
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Re: [lvc-project] [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
2024-01-10 8:43 ` Tali Perry
@ 2024-01-10 9:23 ` Fedor Pchelkin
2024-02-03 20:44 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Fedor Pchelkin @ 2024-01-10 9:23 UTC (permalink / raw)
To: Tali Perry
Cc: Rand Deeb, lvc-project, voskresenski.stanislav, Benjamin Fair,
Avi Fishman, Patrick Venture, openbmc, linux-kernel, Nancy Yuen,
linux-i2c, deeb.rand, Tomer Maimon
On 24/01/10 10:43AM, Tali Perry wrote:
> On Tue, Jan 9, 2024 at 4:52 PM Rand Deeb <rand.sec96@gmail.com> wrote:
> >
> > In the npcm_i2c_reg_slave function, a potential NULL pointer dereference
> > issue occurs when 'client' is NULL. This patch adds a proper NULL check for
> > 'client' at the beginning of the function to prevent undefined behavior.
> >
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> > Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
> > ---
> > drivers/i2c/busses/i2c-npcm7xx.c | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> > index c1b679737240..cfabfb50211d 100644
> > --- a/drivers/i2c/busses/i2c-npcm7xx.c
> > +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> > @@ -1243,13 +1243,14 @@ static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus)
> > static int npcm_i2c_reg_slave(struct i2c_client *client)
> > {
> > unsigned long lock_flags;
> > - struct npcm_i2c *bus = i2c_get_adapdata(client->adapter);
> > -
> > - bus->slave = client;
> > + struct npcm_i2c *bus;
> >
> > - if (!bus->slave)
> > + if (!client)
> > return -EINVAL;
> >
> > + bus = i2c_get_adapdata(client->adapter);
> > + bus->slave = client;
> > +
> > if (client->flags & I2C_CLIENT_TEN)
> > return -EAFNOSUPPORT;
> >
> > --
> > 2.34.1
> >
>
>
> Thanks for the patch!
>
> Reviewed-by:tali.perry1@gmail.com
If I'm not missing something, npcm_i2c_reg_slave() is called via a
function pointer ->reg_slave here [1]. And seems `client` can't be NULL
there. Other drivers implementing ->reg_slave function don't check its
argument.
Maybe we should just drop `if (!bus->slave)` check?
[1]: https://elixir.bootlin.com/linux/latest/source/drivers/i2c/i2c-core-slave.c#L48
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Re: [lvc-project] [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
2024-01-10 9:23 ` Re: [lvc-project] " Fedor Pchelkin
@ 2024-02-03 20:44 ` Wolfram Sang
2024-02-04 8:54 ` Fedor Pchelkin
0 siblings, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2024-02-03 20:44 UTC (permalink / raw)
To: Fedor Pchelkin
Cc: Tali Perry, Rand Deeb, lvc-project, voskresenski.stanislav,
Benjamin Fair, Avi Fishman, Patrick Venture, openbmc,
linux-kernel, Nancy Yuen, linux-i2c, deeb.rand, Tomer Maimon
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> If I'm not missing something, npcm_i2c_reg_slave() is called via a
> function pointer ->reg_slave here [1]. And seems `client` can't be NULL
> there. Other drivers implementing ->reg_slave function don't check its
> argument.
Correct, we trust ourselves here.
> Maybe we should just drop `if (!bus->slave)` check?
Yes.
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Re: Re: [lvc-project] [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
2024-02-03 20:44 ` Wolfram Sang
@ 2024-02-04 8:54 ` Fedor Pchelkin
2024-02-04 10:12 ` Rand Deeb
0 siblings, 1 reply; 6+ messages in thread
From: Fedor Pchelkin @ 2024-02-04 8:54 UTC (permalink / raw)
To: Wolfram Sang, Rand Deeb
Cc: Tali Perry, lvc-project, voskresenski.stanislav, Benjamin Fair,
Avi Fishman, Patrick Venture, openbmc, linux-kernel, Nancy Yuen,
linux-i2c, deeb.rand, Tomer Maimon
On 24/02/03 09:44PM, Wolfram Sang wrote:
>
> > If I'm not missing something, npcm_i2c_reg_slave() is called via a
> > function pointer ->reg_slave here [1]. And seems `client` can't be NULL
> > there. Other drivers implementing ->reg_slave function don't check its
> > argument.
>
> Correct, we trust ourselves here.
>
> > Maybe we should just drop `if (!bus->slave)` check?
>
> Yes.
>
Okay, thanks for confirmation.
Rand, would you like to prepare the patch, please?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Re: Re: [lvc-project] [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave
2024-02-04 8:54 ` Fedor Pchelkin
@ 2024-02-04 10:12 ` Rand Deeb
0 siblings, 0 replies; 6+ messages in thread
From: Rand Deeb @ 2024-02-04 10:12 UTC (permalink / raw)
To: Fedor Pchelkin
Cc: Wolfram Sang, Tali Perry, lvc-project, voskresenski.stanislav,
Benjamin Fair, Avi Fishman, Patrick Venture, openbmc,
linux-kernel, Nancy Yuen, linux-i2c, deeb.rand, Tomer Maimon
On Sun, Feb 4, 2024 at 11:54 AM Fedor Pchelkin <pchelkin@ispras.ru> wrote:
>
> On 24/02/03 09:44PM, Wolfram Sang wrote:
> >
> > > If I'm not missing something, npcm_i2c_reg_slave() is called via a
> > > function pointer ->reg_slave here [1]. And seems `client` can't be NULL
> > > there. Other drivers implementing ->reg_slave function don't check its
> > > argument.
> >
> > Correct, we trust ourselves here.
> >
> > > Maybe we should just drop `if (!bus->slave)` check?
> >
> > Yes.
> >
>
> Okay, thanks for confirmation.
>
> Rand, would you like to prepare the patch, please?
>
Hi Fedor!,
Sure, In fact, there were two scenarios from the beginning, either
redundant condition or potential NULL pointer dereference.I relied on
the condition to determine the type of issue because I did not find
it logical to add a useless condition, but based on the Wolfram Sang
words "we trust ourselves here." then the scenario will change to
redundant condition, so i'll write a new patch and send it in new
thread.
^ permalink raw reply [flat|nested] 6+ messages in thread
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Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2024-01-09 14:51 [PATCH] i2c: Fix NULL pointer dereference in npcm_i2c_reg_slave Rand Deeb
2024-01-10 8:43 ` Tali Perry
2024-01-10 9:23 ` Re: [lvc-project] " Fedor Pchelkin
2024-02-03 20:44 ` Wolfram Sang
2024-02-04 8:54 ` Fedor Pchelkin
2024-02-04 10:12 ` Rand Deeb
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