[PATCH v2 0/1] i2c: mv64xxx: prevent illegal pointer access

[PATCH v2 0/1] i2c: mv64xxx: prevent illegal pointer access

[enachman]

From: Elad Nachman <enachman@marvell.com>

v2:
  1) rewrap commit message

Elad Nachman (1):
  i2c: mv64xxx: prevent illegal pointer access

 drivers/i2c/busses/i2c-mv64xxx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

-- 
2.25.1

[PATCH v2 1/1] i2c: mv64xxx: prevent illegal pointer access

[enachman]

From: Elad Nachman <enachman@marvell.com>

Spurious interrupts left while i2c controller still at RX or TX state
would try to access the RX or TX buffer pointer, which is NULL.
Add check to verify buffer pointer is not NULL before reading or writing
the buffer for additional TX or RX operations.

Signed-off-by: Elad Nachman <enachman@marvell.com>
---
 drivers/i2c/busses/i2c-mv64xxx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 8fc26a511320..e6baa9c520b4 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -390,14 +390,18 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
 		break;
 
 	case MV64XXX_I2C_ACTION_SEND_DATA:
-		writel(drv_data->msg->buf[drv_data->byte_posn++],
-			drv_data->reg_base + drv_data->reg_offsets.data);
+		if (drv_data->msg && drv_data->msg->buf)
+			writel(drv_data->msg->buf[drv_data->byte_posn++],
+				drv_data->reg_base + drv_data->reg_offsets.data);
 		writel(drv_data->cntl_bits,
 			drv_data->reg_base + drv_data->reg_offsets.control);
 		break;
 
 	case MV64XXX_I2C_ACTION_RCV_DATA:
-		drv_data->msg->buf[drv_data->byte_posn++] =
+		if (drv_data->msg && drv_data->msg->buf)
+			drv_data->msg->buf[drv_data->byte_posn++] =
+				readl(drv_data->reg_base + drv_data->reg_offsets.data);
+		else
 			readl(drv_data->reg_base + drv_data->reg_offsets.data);
 		writel(drv_data->cntl_bits,
 			drv_data->reg_base + drv_data->reg_offsets.control);
-- 
2.25.1

Re: [PATCH v2 0/1] i2c: mv64xxx: prevent illegal pointer access

[Markus Elfring]

…
> v2:
>   1) rewrap commit message
…

You may omit a cover letter for a single patch,
don't you?

Regards,
Markus

Re: [PATCH v2] i2c: mv64xxx: prevent illegal pointer access

[Markus Elfring]

…
> Add check to verify buffer pointer is not NULL before reading or writing
> the buffer for additional TX or RX operations.

How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16#n145

Regards,
Markus