Re: [PATCH] arch: x86: platform: intel-mid: sfi.c: Cleaning up missing null-terminate in conjunction with strncpy

From: David Cohen
Date: Mon Aug 11 2014 - 12:57:49 EST


Hi Rickard,

Sorry for the late reply. Just came back from vacation :)

On Sun, Jul 27, 2014 at 12:26:58AM +0200, Rickard Strandqvist wrote:
> If you are going to use memset before strncpy you must copy sizeof -1

I agree it is way safer to not reply on firmware to have the null
terminator in place. But can you provide a better patch description? :)
It would be better if it is not a line addressed directly to the author.
Please refer the null terminator concern too.

Br, David

>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/platform/intel-mid/sfi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/platform/intel-mid/sfi.c b/arch/x86/platform/intel-mid/sfi.c
> index 994c40b..97e79c9 100644
> --- a/arch/x86/platform/intel-mid/sfi.c
> +++ b/arch/x86/platform/intel-mid/sfi.c
> @@ -359,7 +359,7 @@ static void __init sfi_handle_spi_dev(struct sfi_device_table_entry *pentry,
> void *pdata = NULL;
>
> memset(&spi_info, 0, sizeof(spi_info));
> - strncpy(spi_info.modalias, pentry->name, SFI_NAME_LEN);
> + strncpy(spi_info.modalias, pentry->name, sizeof(spi_info.modalias) - 1);
> spi_info.irq = ((pentry->irq == (u8)0xff) ? 0 : pentry->irq);
> spi_info.bus_num = pentry->host_num;
> spi_info.chip_select = pentry->addr;
> @@ -389,7 +389,7 @@ static void __init sfi_handle_i2c_dev(struct sfi_device_table_entry *pentry,
> void *pdata = NULL;
>
> memset(&i2c_info, 0, sizeof(i2c_info));
> - strncpy(i2c_info.type, pentry->name, SFI_NAME_LEN);
> + strncpy(i2c_info.type, pentry->name, sizeof(i2c_info.type) - 1);
> i2c_info.irq = ((pentry->irq == (u8)0xff) ? 0 : pentry->irq);
> i2c_info.addr = pentry->addr;
> pr_debug("I2C bus = %d, name = %16.16s, irq = 0x%2x, addr = 0x%x\n",
> --
> 1.7.10.4
>
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