From: Anthony PERARD <anthony.perard@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH v5 08/14] hvmloader: Locate the BIOS blob
Date: Fri, 24 Jun 2016 18:02:41 +0100 [thread overview]
Message-ID: <20160624170241.GY5666@perard.uk.xensource.com> (raw)
In-Reply-To: <576CFE7902000078000F85FF@prv-mh.provo.novell.com>
On Fri, Jun 24, 2016 at 01:33:45AM -0600, Jan Beulich wrote:
> >>> On 22.06.16 at 19:15, <anthony.perard@citrix.com> wrote:
> > --- a/tools/firmware/hvmloader/hvmloader.c
> > +++ b/tools/firmware/hvmloader/hvmloader.c
> > @@ -253,10 +253,51 @@ static void acpi_enable_sci(void)
> > BUG_ON(!(pm1a_cnt_val & ACPI_PM1C_SCI_EN));
> > }
> >
> > +const struct hvm_modlist_entry *get_module_entry(
> > + const struct hvm_start_info *info,
> > + const char *name)
> > +{
> > + const struct hvm_modlist_entry *modlist =
> > + (struct hvm_modlist_entry *)(uint32_t)info->modlist_paddr;
> > + unsigned int i;
> > +
> > + if ( !modlist || info->modlist_paddr > UINT_MAX)
> > + return NULL;
>
> How about info->modlist_paddr + info->nr_modules * sizeof()?
> You check for overflow below, but not here. I think you should
> either consistently rely on there being something right below 4Gb
> which makes this impossible (and then say so in a comment), or
> do full checks everywhere.
I'll do the full checks.
> > + for ( i = 0; i < info->nr_modules; i++ )
> > + {
> > + uint32_t module_name = modlist[i].cmdline_paddr;
> > +
> > + /* Skip if the module or its cmdline is missing. */
> > + if ( !module_name || !modlist[i].paddr )
> > + continue;
> > +
> > + /* Skip if the cmdline can not be read. */
> > + if ( modlist[i].cmdline_paddr > UINT_MAX )
> > + continue;
>
> Similarly here.
Here, I don't know the size of the cmdline and I don't think calling an
extra strlen() would be usefull. I think that the strcmp() below is going to
be enough for the top bondary check.
Or I could use the size of name.
> > + if ( !strcmp(name, (char*)module_name) )
>
> Stray cast.
Yes. I'll change the type of module_name and remove the cast here.
> > + {
> > + if ( modlist[i].paddr > UINT_MAX || modlist[i].size > UINT_MAX ||
> > + (modlist[i].paddr + modlist[i].size) > UINT_MAX )
>
> I think the last one could be >=.
I think it's valid if addr+size == UINT_MAX. That would means the last
byte of the module would be at 0xFFFFFFFE.
--
Anthony PERARD
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next prev parent reply other threads:[~2016-06-24 17:02 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 17:15 [PATCH v5 00/14] Load BIOS via toolstack instead of been embedded in hvmloader Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 01/14] libxc: Rework extra module initialisation Anthony PERARD
2016-07-07 14:55 ` Wei Liu
2016-07-08 10:52 ` Anthony PERARD
2016-07-08 11:29 ` Wei Liu
2016-07-08 13:26 ` Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 02/14] libxc: Prepare a start info structure for hvmloader Anthony PERARD
2016-06-23 14:44 ` Boris Ostrovsky
2016-06-23 16:52 ` Anthony PERARD
2016-07-07 14:55 ` Wei Liu
2016-07-08 10:55 ` Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 03/14] configure: #define SEABIOS_PATH and OVMF_PATH Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 04/14] firmware/makefile: install BIOS blob Anthony PERARD
2016-07-07 14:55 ` Wei Liu
2016-06-22 17:15 ` [PATCH v5 05/14] libxl: Load guest BIOS from file Anthony PERARD
2016-06-24 7:23 ` Jan Beulich
2016-06-24 14:20 ` Anthony PERARD
2016-07-07 14:55 ` Wei Liu
2016-06-22 17:15 ` [PATCH v5 06/14] xen: Move the hvm_start_info C representation from libxc to public/xen.h Anthony PERARD
2016-07-07 14:55 ` Wei Liu
2016-07-07 15:07 ` Jan Beulich
2016-07-07 15:28 ` Wei Liu
2016-07-08 9:53 ` Julien Grall
2016-07-07 15:02 ` Andrew Cooper
2016-07-07 15:09 ` Jan Beulich
2016-07-07 15:12 ` Andrew Cooper
2016-06-22 17:15 ` [PATCH v5 07/14] hvmloader: Grab the hvm_start_info pointer Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 08/14] hvmloader: Locate the BIOS blob Anthony PERARD
2016-06-24 7:33 ` Jan Beulich
2016-06-24 17:02 ` Anthony PERARD [this message]
2016-06-27 7:13 ` Jan Beulich
2016-06-30 15:04 ` Anthony PERARD
2016-07-01 6:40 ` Jan Beulich
2016-06-22 17:15 ` [PATCH v5 09/14] hvmloader: Check modules whereabouts in perform_tests Anthony PERARD
2016-06-24 7:44 ` Jan Beulich
2016-06-24 17:14 ` Anthony PERARD
2016-06-27 7:20 ` Jan Beulich
2016-06-22 17:15 ` [PATCH v5 10/14] hvmloader: Load SeaBIOS from hvm_start_info modules Anthony PERARD
2016-06-24 7:46 ` Jan Beulich
2016-06-22 17:15 ` [PATCH v5 11/14] hvmloader: Load OVMF from modules Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 12/14] hvmloader: bios->bios_load() now needs to be defined Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 13/14] hvmloader: Always build-in SeaBIOS and OVMF loader Anthony PERARD
2016-06-22 17:15 ` [PATCH v5 14/14] configure: do not depend on SEABIOS_PATH or OVMF_PATH Anthony PERARD
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