On Wed, Sep 16, 2020 at 7:15 PM Chris Johns <chr...@rtems.org> wrote: > > On 17/9/20 9:50 am, Joel Sherrill wrote: > > On Wed, Sep 16, 2020, 6:43 PM Chris Johns <chr...@rtems.org > > <mailto:chr...@rtems.org>> wrote: > > > > On 16/9/20 11:42 pm, Joel Sherrill wrote: > > > snprintf() is a safe method and I strongly disagree with the blanket > > replacement > > > of many safe methods with memcpy(). > > > > > > Based on what POSIX profiles snprintf() is included in and the safety > > and > > > security requirements those profiles are designed to meet, snprintf() > > is > > > supported by RTOSes that can meet DO-178 Level A. > > > > > > If the POSIX method being reviewed is in the FACE Safety Base or > > Safety > > Extended > > > profile, then it is OK to use and has been used in flight qualified > > > applications. And that is a general statement meaning running on any > > of a > > > variety of RTOSes. If the usage is incorrect, let's fix it but blanket > > changing > > > them is wrong. > > > > This is really good information, thank you. > > > > No problem. That doesn't mean you can't do something stupid with it but > > sprintf() would be discouraged and isn't in those profiles as I recall. > > > > I see EPICS is reporting similar issues at the moment and looking to > > work around > > them. > > > > And no one is questioning why? What's the risk? > > > > Is there a history of why this has been added to compilers as a warning? > > > > I have no idea..snprintf has a length and avoids overwrites. > > > > I would suggest that we find a safety or security coding standard that warns > > about whatever methods this catches. > > > > Personally replacing snprintf and strong operations with memmove is > > semantically > > wrong. > > I found this.... > > https://developers.redhat.com/blog/2018/05/24/detecting-string-truncation-with-gcc-8/ > > The "Handling Truncation When It Occurs" section in the blog post is something > worth considering. It seems the return value of call should be checked. That > seems reasonable. >
Nice. *printf also suffer from other security-relevant vulnerabilities such as the format-string attack: https://owasp.org/www-community/attacks/Format_string_attack This means replacing their use with alternatives can be generally more secure. > Chris > _______________________________________________ > devel mailing list > devel@rtems.org > http://lists.rtems.org/mailman/listinfo/devel _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
