[PATCH 6.6 069/166] i2c: s3c24xx: check the size of the SMBUS message before using it

Greg Kroah-Hartman
2026-04-24T13:36:28Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit c0128c7157d639a931353ea344fb44aad6d6e17a upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i2c/busses/i2c-s3c2410.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -504,8 +504,13 @@ static int i2c_s3c_irq_nextbyte(struct s
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 */