[PATCH] D32346: [clang-tidy] New readability check for strlen argument
Alexander Kornienko via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Mon May 22 06:48:05 PDT 2017
alexfh requested changes to this revision.
alexfh added inline comments.
This revision now requires changes to proceed.
Comment at: docs/clang-tidy/checks/readability-strlen-argument.rst:20
+ char *p = new char[(strlen(s) - 1)]
+ strcpy(p, s);
> danielmarjamaki wrote:
> > JonasToth wrote:
> > > isnt that an overflow?
> > > an example:
> > > `strlen(s) == 10` -> `p` will be 9 characters long, since its substracted with `1`.
> > >
> > > the copy operation will then copy the content of `s` into `p`, therefore copying 10 characters into a buffer of length 9.
> > >
> > > as i understand it `strcpy(p, s + 1)` would be correct with the sizes.
> > yes it is overflow. My intention was to show that strlen(s+1) syntax is dangerous.
> ok. please state that the overflow in a comment, its better to make that explicit.
BTW, `strlen(x) - N` is not only prone to overflows, but also less efficient (in case it's intentional). Did you run the check on real projects to see how likely this pattern is a bug?
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