Return-Path: From: Szymon Janc To: Johan Hedberg Cc: Andrei Emeltchenko , linux-bluetooth@vger.kernel.org Subject: Re: [RFC] Fix eir parsing function. Date: Fri, 29 Nov 2013 09:39:22 +0100 Message-ID: <1501205.ZvMV0NcIeM@uw000953> In-Reply-To: <20131129082247.GA6800@x220.p-661hnu-f1> References: <1385712049-24635-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> <20131129082247.GA6800@x220.p-661hnu-f1> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi, > Hi Andrei, > > On Fri, Nov 29, 2013, Andrei Emeltchenko wrote: > > Currently eir_parse always return 0 but it is checked throughout the > > code (in android/bluetooth code as well in src/adapteri, etc) for > > return value (err < 0) which never happens. Return -1 if there is > > nothing to parse. Send as RFC as I do not know how current code supposed > > to be working. > > --- > > src/eir.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/src/eir.c b/src/eir.c > > index 084884e..f7450c9 100644 > > --- a/src/eir.c > > +++ b/src/eir.c > > @@ -138,7 +138,7 @@ int eir_parse(struct eir_data *eir, const uint8_t *eir_data, uint8_t eir_len) > > > > /* No EIR data to parse */ > > if (eir_data == NULL) > > - return 0; > > + return -1; > > > > while (len < eir_len - 1) { > > uint8_t field_len = eir_data[0]; > > I think the only concern here is "when is it safe to call > eir_data_free()?". If it would not be safe to call that in case the > eir_parse function "fails" then we'd need to be able to clearly > distinguish failure though a -1 return value. However, as it now stands > it is always safe to call eir_data_free() on a struct that was passed to > eir_parse(), so I'd go for simply changing this function to return void > instead of int. I think it should be possible to check if parsing failed due to invalid EIR but I think parsing empty EIR should not result in error. Most callers do verify eir_len or buffer validity before calling eir_parse() anyway so I would change this check to: if (!eir_data || !eir_len) return 0; and simplify callers code. -- BR Szymon Janc