[PATCH] cgit: use strtol_i instead of atoi

Jamie Couture jamie.couture at gmail.com
Wed May 13 16:57:00 CEST 2015

On Wed, May 13, 2015 at 02:45:56PM +0100, John Keeping wrote:
> On Wed, May 13, 2015 at 02:41:24PM +0100, John Keeping wrote:
> > On Wed, May 13, 2015 at 03:35:29PM +0200, Jason A. Donenfeld wrote:
> > > Anybody have any objections to this? In some cases it's slightly more
> > > verbose, but otherwise, I can't see any downsides.
> > 
> > It's worse if there is trailing data.  Since there's nothing obvious we
> > can do if the input is bad, I'm not sure how much we care (i.e. ignoring
> > the return value from strtol_i is OK) but whereas atoi will parse a
> > valid value followed by trailing garbage strtol_i will just fail.
> > 
> > Worse than that, if it fails it leaves the result uninitialized, which
> > doesn't matter in the cases where we just update a variable, but at
> > least one part of this patch introduces a new variable that is not set
> > if strtol_i fails.
> Oops... I didn't double-check the patch before sending, it does always
> initialize the variables first so the only worry is trailing garbage.
> Of course, if atoi leads to SQL injection, what makes strtol safe?  The
> test seems fundamentally useless; AFAICT the whole point is that if I
> parse some user input and use without validating it then I can end up
> doing something like:
> 	int num_items = <user input>;
> 	items = malloc(num_items * sizeof(*items));
> leading to integer overflow.  But the mechanism used to convert the user
> input from a string to an integer is completely irrelevant.


I'm not familiar with the utility, but can nessus have exceptions to
a rule?   In cgit's case, I don't see the use of atoi() as a problem
in this context.

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