[cfe-dev] RFC: default to -Werror=format-security

[Aaron Ballman via cfe-dev]

On Tue, Feb 16, 2016 at 3:44 PM, Nico Weber via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
> On Tue, Feb 16, 2016 at 12:22 PM, Craig, Ben <ben.craig at codeaurora.org>
> wrote:
>>
>>
>> On 2/16/2016 1:18 PM, Nico Weber via cfe-dev wrote:
>>>
>>>
>>> Won't this line of reasoning lead to all useful warnings being in -Werror
>>> eventually? Say, forgetting a return statement in a function is also "just"
>>> a warning...
>>
>>
>> Not all of them :)
>>
>> Visual Studio groups warnings into big warning level buckets.  Level 1 has
>> the most important / severe (obvious use of uninitialized value), level 4
>> has fairly minor warnings (unused parameter), and /Weverything will tell you
>> about really useless stuff (warning! you just used __declspec(align)! ).  I
>> could imagine a world where the "Level 1", and maybe "Level 2" warnings were
>> errors by default.
>
>
> We have this too: on-by-default warnings, -Wall, -Wextra, -Weverything. I
> don't think we should turn on-by-default warnings into errors.

We already do (in fact, we have over two dozen that we turn on,
according to the list posted earlier in the thread).

>
>>
>>
>> We should make it harder to compile broken code, and easier to write
>> correct code.  We can't change it all at once without angering the world
>> though :)
>
>
> People who don't like writing broken code don't ignore warnings. People who
> do like writing broken code will just pass -Wno-error. I don't think this
> proposal helps either party.

I think there's a reasonable distinction between "this code may not do
what you expect" and "this code may not do what you expect, and is
likely to result in security vulnerabilities." If someone elects to
turn on -Wno-error to get their insecure code to compile, there's
basically no help for them. But for projects that don't compile
particularly cleanly (so security-related diagnostics get lost in the
noise), being alerted, "no, really, this is bad" will definitely help
*some* programmers. I am interested in alerting people who might be
willing to fix security vulnerabilities in their code. I'm unconcerned
about people who will go to any lengths to get their code to compile
without actually fixing their code when it comes to security concerns.

~Aaron

>
>>
>>
>>
>> --
>> Employee of Qualcomm Innovation Center, Inc.
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
>> Foundation Collaborative Project
>>
>
>
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