On Tue, Sep 15, 2015 at 11:36 AM, Jeff King <p...@peff.net> wrote: > We sometimes sprintf into static buffers when we know that > the size of the buffer is large enough to fit the input > (either because it's a constant, or because it's numeric > input that is bounded in size). Likewise with strcpy of > constant strings. > > However, these sites make it hard to audit sprintf and > strcpy calls for buffer overflows, as a reader has to > cross-reference the size of the array with the input. Let's > use xsnprintf instead, which communicates to a reader that > we don't expect this to overflow (and catches the mistake in > case we do). > > Signed-off-by: Jeff King <p...@peff.net> > --- > diff --git a/builtin/merge-index.c b/builtin/merge-index.c > index 1a1eafa..1d66111 100644 > --- a/builtin/merge-index.c > +++ b/builtin/merge-index.c > @@ -23,7 +23,7 @@ static int merge_entry(int pos, const char *path) > break; > found++; > strcpy(hexbuf[stage], sha1_to_hex(ce->sha1)); > - sprintf(ownbuf[stage], "%o", ce->ce_mode); > + xsnprintf(ownbuf[stage], sizeof(ownbuf[stage]), "%o", > ce->ce_mode);
Interesting. I wonder if there are any (old/broken) compilers which would barf on this. If we care, perhaps sizeof(ownbuf[0]) instead? > arguments[stage] = hexbuf[stage]; > arguments[stage + 4] = ownbuf[stage]; > } while (++pos < active_nr); -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
