linux-kernel - Re: [PATCH v4 06/14] of: property: Avoiding using uninitialized variable @imaplen in parse_interrupt

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <jmwcuelvywejhgy3mjo4y4odewirotlagmlahevsh2kicrakey@qvdajicxn7tc>
Date: Sat, 11 Jan 2025 10:01:07 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Zijun Hu <zijun_hu@...oud.com>
Cc: Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>, 
	Maxime Ripard <mripard@...nel.org>, Robin Murphy <robin.murphy@....com>, 
	Grant Likely <grant.likely@...retlab.ca>, Marc Zyngier <maz@...nel.org>, 
	Andreas Herrmann <andreas.herrmann@...xeda.com>, Marek Szyprowski <m.szyprowski@...sung.com>, 
	Catalin Marinas <catalin.marinas@....com>, Mike Rapoport <rppt@...nel.org>, 
	Oreoluwa Babatunde <quic_obabatun@...cinc.com>, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Zijun Hu <quic_zijuhu@...cinc.com>
Subject: Re: [PATCH v4 06/14] of: property: Avoiding using uninitialized
 variable @imaplen in parse_interrupt_map()

On Sat, Jan 11, 2025 at 06:34:21AM +0800, Zijun Hu wrote:
> On 2025/1/11 04:26, Rob Herring wrote:
> > On Thu, Jan 09, 2025 at 09:26:57PM +0800, Zijun Hu wrote:
> >> From: Zijun Hu <quic_zijuhu@...cinc.com>
> >>
> >> parse_interrupt_map() will use uninitialized variable @imaplen if fails
> >> to get property 'interrupt-map'.
> >>
> >> Fix by using the variable after successfully getting the property.
> >>
> >> Fixes: e7985f43609c ("of: property: Fix fw_devlink handling of interrupt-map")
> >> Signed-off-by: Zijun Hu <quic_zijuhu@...cinc.com>
> >> ---
> >>  drivers/of/property.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/of/property.c b/drivers/of/property.c
> >> index dca1a3ebccae1093b2b11f51e8e692bca854d0e3..6245cbff3527d762c16e7f4b7b7b3d4f2e9ddbe6 100644
> >> --- a/drivers/of/property.c
> >> +++ b/drivers/of/property.c
> >> @@ -1391,9 +1391,9 @@ static struct device_node *parse_interrupt_map(struct device_node *np,
> >>  	addrcells = of_bus_n_addr_cells(np);
> >>  
> >>  	imap = of_get_property(np, "interrupt-map", &imaplen);
> >> -	imaplen /= sizeof(*imap);
> >>  	if (!imap)
> >>  		return NULL;
> >> +	imaplen /= sizeof(*imap);
> > 
> > sizeof() is a compile time constant, there's not an actual dereference 
> > here.
> > 
> 
> the uninitialized variable is @imaplen, and not sizeof(*imap).

Correct. I think error is harmless, because whatever stack/random value
of imaplen we use in 'imaplen / =sizeof', we immediately return.

Anyway, for code correctness and silencing whatever warnings there are
(if there are you should actually paste them in commit msg):

Reviewed-by: Krzysztof Kozlowski <krzk@...nel.org>

Best regards,
Krzysztof