Re: [Xen-devel] [PATCH v2 for-4.7 10/14] libxl: add the printf-like attributes to a couple of functions

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 26/04/16 16:29, Wei Liu wrote:
> On Tue, Apr 26, 2016 at 04:52:19PM +0200, Roger Pau Monne wrote:
> [...]
>> @@ -1995,9 +1995,10 @@ _hidden libxl__json_object 
>> *libxl__json_parse(libxl__gc *gc_opt, const char *s);
>>  _hidden int libxl__device_model_version_running(libxl__gc *gc, uint32_t 
>> domid);
>>    /* Return the system-wide default device model */
>>  _hidden libxl_device_model_version libxl__default_device_model(libxl__gc 
>> *gc);
>> -_hidden char *libxl__device_model_xs_path(libxl__gc *gc, uint32_t dm_domid,
>> -                                          uint32_t domid,
>> -                                          const char *format, ...) 
>> PRINTF_ATTRIBUTE(4, 5);
> Why does this not work with clang?

It is a security consideration.

Passing anything other than a string literal to a printf-style function
is opening a can of worms if an untrusted entity can influence the
content of the string.

I guess clang is better at spotting parameters passed like this than GCC.

~Andrew

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