[PATCH] char: tpm: fix error return code in tpm_cr50_i2c_tis_recv()

[PATCH] char: tpm: fix error return code in tpm_cr50_i2c_tis_recv()

[Zhihao Cheng]

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 3a253caaad11 ("char: tpm: add i2c driver for cr50")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
---
 drivers/char/tpm/tpm_tis_i2c_cr50.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/tpm/tpm_tis_i2c_cr50.c
index ec9a65e7887d..e908da78fbf4 100644
--- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
+++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
@@ -483,6 +483,7 @@ static int tpm_cr50_i2c_tis_recv(struct tpm_chip *chip, u8 *buf, size_t buf_len)
 	expected = be32_to_cpup((__be32 *)(buf + 2));
 	if (expected > buf_len) {
 		dev_err(&chip->dev, "Buffer too small to receive i2c data\n");
+		rc = -EIO;
 		goto out_err;
 	}
 
-- 
2.25.4

Re: [PATCH] char: tpm: fix error return code in tpm_cr50_i2c_tis_recv()

[Jarkko Sakkinen]

On Thu, Apr 08, 2021 at 07:26:08PM +0800, Zhihao Cheng wrote:
> Fix to return a negative error code from the error handling
> case instead of 0, as done elsewhere in this function.
> 
> Fixes: 3a253caaad11 ("char: tpm: add i2c driver for cr50")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
> ---
>  drivers/char/tpm/tpm_tis_i2c_cr50.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> index ec9a65e7887d..e908da78fbf4 100644
> --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
> +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> @@ -483,6 +483,7 @@ static int tpm_cr50_i2c_tis_recv(struct tpm_chip *chip, u8 *buf, size_t buf_len)
>  	expected = be32_to_cpup((__be32 *)(buf + 2));
>  	if (expected > buf_len) {
>  		dev_err(&chip->dev, "Buffer too small to receive i2c data\n");
> +		rc = -EIO;
>  		goto out_err;
>  	}
>  
> -- 
> 2.25.4
> 

We are using E2BIG in similar situations in a few places:

❯ git grep E2BIG drivers/char/tpm
drivers/char/tpm/tpm-dev-common.c:              return -E2BIG;
drivers/char/tpm/tpm-interface.c:               return -E2BIG;
drivers/char/tpm/tpm_crb.c:             return -E2BIG;
drivers/char/tpm/tpm_i2c_atmel.c:               return -E2BIG;
drivers/char/tpm/tpm_i2c_infineon.c:            return -E2BIG;

So, I tend to think that also in here it'd be better to use E2BIG.

/Jarkko