Re: [PATCH] staging: android: Replace strcpy with strlcpy

[Al Viro]

On Sun, Mar 12, 2017 at 02:10:01AM +0530, simran singhal wrote:
> Replace strcpy with strlcpy as strcpy does not check for buffer
> overflow.
> This is found using Flawfinder.
> 
> Signed-off-by: simran singhal <singhalsimr...@gmail.com>
> ---
>  drivers/staging/android/ashmem.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/android/ashmem.c 
> b/drivers/staging/android/ashmem.c
> index 7cbad0d..eb2f4ef 100644
> --- a/drivers/staging/android/ashmem.c
> +++ b/drivers/staging/android/ashmem.c
> @@ -548,7 +548,8 @@ static int set_name(struct ashmem_area *asma, void __user 
> *name)
>       if (unlikely(asma->file))
>               ret = -EINVAL;
>       else
> -             strcpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name);
> +             strlcpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name,
> +                     sizeof(asma->name + ASHMEM_NAME_PREFIX_LEN));

Trivial C quiz: given

struct ashmem_area {
        char name[ASHMEM_FULL_NAME_LEN];
        struct list_head unpinned_list;
        struct file *file;
        size_t size;
        unsigned long prot_mask;
};
static int set_name(struct ashmem_area *asma, void __user *name)

what, in your opinion, would be
        1) type of asma->name
        2) type of asma->name + ASHMEM_NAME_PREFIX_LEN
        3) value of sizeof(asma->name + ASHMEM_NAME_PREFIX_LEN)
As a bonus question,
        4) what is the value of this kind of patches?

<rot13 answers>
        1) NFUZRZ_SHYY_ANZR_YRA-ryrzrag neenl bs pune
        2) cbvagre gb pune
        3) fvmr bs n cbvagre
        4) fbpvbybtvpny - ernql-znqr vyyhfgengvbaf bs crevyf bs
pnetb phyg.