i2c: s3c24xx: check the size of the SMBUS message before using it

The first byte of an i2c SMBUS message is the size, and it should be
verified to ensure that it is in the range of 0..I2C_SMBUS_BLOCK_MAX
before processing it.

This is the same logic that was added in commit a6e04f05ce0b ("i2c:
tegra: check msg length in SMBUS block read") to the i2c tegra driver.

Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Andi Shyti <andi.shyti@kernel.org>
Cc: stable <stable@kernel.org>
Assisted-by: gkh_clanker_2000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/2026022314-rely-scrubbed-4839@gregkh

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 8138f5ef40f06b7f2a3a2e5201d49ad32bc560e9..15e14a6fe6dce97ddd5d049b405ed7707fc12dff 100644 (file)
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -503,8 +503,13 @@ static void i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
                i2c->msg->buf[i2c->msg_ptr++] = byte;
 
                /* Add actual length to read for smbus block read */
-               if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
+               if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1) {
+                       if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX) {
+                               s3c24xx_i2c_stop(i2c, -EPROTO);
+                               break;
+                       }
                        i2c->msg->len += byte;
+               }
  prepare_read:
                if (is_msglast(i2c)) {
                        /* last byte of buffer */