Re: [PATCH 1/5] kallsyms: pass buffer size in sprint_* APIs

[Waiman Long]

On 5/20/22 04:36, Maninder Singh wrote:
> As of now sprint_* APIs don't pass buffer size as an argument
> and use sprintf directly.
>
> To replace dangerous sprintf API to scnprintf,
> buffer size is required in arguments.
>
> Co-developed-by: Onkarnath <onkarnath.1@xxxxxxxxxxx>
> Signed-off-by: Onkarnath <onkarnath.1@xxxxxxxxxxx>
> Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
> ---
>   arch/s390/lib/test_unwind.c    |  2 +-
>   drivers/scsi/fnic/fnic_trace.c |  8 ++++----
>   include/linux/kallsyms.h       | 20 ++++++++++----------
>   init/main.c                    |  2 +-
>   kernel/kallsyms.c              | 27 ++++++++++++++++-----------
>   kernel/trace/trace_output.c    |  2 +-
>   lib/vsprintf.c                 | 10 +++++-----
>   7 files changed, 38 insertions(+), 33 deletions(-)
>
> diff --git a/arch/s390/lib/test_unwind.c b/arch/s390/lib/test_unwind.c
> index 5a053b393d5c..adbc2b53db16 100644
> --- a/arch/s390/lib/test_unwind.c
> +++ b/arch/s390/lib/test_unwind.c
> @@ -75,7 +75,7 @@ static noinline int test_unwind(struct task_struct *task, struct pt_regs *regs,
>   			ret = -EINVAL;
>   			break;
>   		}
> -		sprint_symbol(sym, addr);
> +		sprint_symbol(sym, KSYM_SYMBOL_LEN, addr);

Instead of hardcoding KSYM_SYMBOL_LEN everywhere, will it better to hide 
it like this:

        extern int __sprint_symbol(char *buffer, size_t size, unsigned 
long address);
        #define sprint_symbol(buf, addr)        __sprint_symbol(buf, 
sizeof(buf), addr)

Or you can use sizeof(buf) directly instead of KSYM_SYMBOL_LEN.

Cheers,
Longman