[Olsr-dev] hardening 1by1: -Wformat -Wformat-security -Werror=format-security

[Ferry Huberts]

On 10-10-12 09:26, Henning Rogge wrote:
> On 10/10/2012 09:14 AM, Ferry Huberts wrote:
>>
>>
>> On 05-10-12 23:34, Hans-Christoph Steiner wrote:
>>>
>>> As part of the effort to get the hardening flags that are default in
>>> Debian to be also default in olsrd, I'm submitting one email per concept
>>> so we can discuss them each.
>>>
>>> The first is "-Wformat -Wformat-security -Werror=format-security".  This
>>> adds strict checks to *printf() formats, which are a common source of
>>> exploits.  olsrd currently passes all of these checks.
>
> I just check the current settings myself (Kubuntu 64 bit, 3.2.0-31
> kernel, gcc 4.6.3), compiling with debug:
>
> CFLAGS: -Wall -Wextra -Wold-style-definition
> -Wdeclaration-after-statement -Wmissing-prototypes -Wstrict-prototypes
> -Wmissing-declarations -Wsign-compare -Waggregate-return
> -Wmissing-noreturn -Wmissing-format-attribute -Wno-multichar
> -Wno-deprecated-declarations -Wendif-labels -Wwrite-strings
> -Wbad-function-cast -Wpointer-arith -Wcast-qual -Wshadow -Wformat
> -Wsequence-point -Wcast-align -Wformat-security -Wformat-y2k -Winit-self
> -Wswitch-default -Wsync-nand -Wundef -Wlogical-op -Wdouble-promotion
> -Wjump-misses-init -Wtrampolines -Wunused-parameter -Wnested-externs
> -Winline -Wdisabled-optimization -finline-functions-called-once
> -funit-at-a-time -fearly-inlining -finline-limit=350   -fPIC -ggdb
>
> LDFLAGS: -Wl,-export-dynamic  -Wl,-rpath,/usr/local/lib
> -Wl,--warn-common -fPIC
>
> Compiling without debug:
>
> CFLAGS: -Wall -Wextra -Wold-style-definition
> -Wdeclaration-after-statement -Wmissing-prototypes -Wstrict-prototypes
> -Wmissing-declarations -Wsign-compare -Waggregate-return
> -Wmissing-noreturn -Wmissing-format-attribute -Wno-multichar
> -Wno-deprecated-declarations -Wendif-labels -Wwrite-strings
> -Wbad-function-cast -Wpointer-arith -Wcast-qual -Wshadow -Wformat
> -Wsequence-point -Wcast-align -Wformat-security -Wformat-y2k -Winit-self
> -Wswitch-default -Wsync-nand -Wundef -Wlogical-op -Wdouble-promotion
> -Wjump-misses-init -Wtrampolines -Wunused-parameter -Wnested-externs
> -Winline -Wdisabled-optimization -finline-functions-called-once
> -funit-at-a-time -fearly-inlining -fomit-frame-pointer
> -finline-limit=350   -fPIC
> LDFLAGS: -Wl,-export-dynamic  -Wl,-rpath,/usr/local/lib
> -Wl,--warn-common -fPI
>
> --------------
> "-Wformat" and "-Wformat-security" are there, "-Werror=format-security"
> is not.

this mail thread was about the format flags ;-)

>
> "-O2" is missing for the non-debug case, as is "-D_FORTIFY_SOURCE=2"
>
> "-fPIE" and "-pie" are also missing.
>
> So we have some of the suggested options, but not all of them.
>
> Henning Rogge
>
>

-- 
Ferry Huberts