Messages in this thread | | | Date | Tue, 8 Feb 2011 16:53:01 +0200 | From | Gleb Natapov <> | Subject | Re: [PATCHv2] Fix EDD3.0 data verification. |
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Peter, ping.
Is this version acceptable?
On Thu, Feb 03, 2011 at 02:29:48PM +0200, Gleb Natapov wrote: > Check for nonzero path in edd_has_edd30() has no sense. First, it looks > at the wrong memory. Device path starts at offset 30 of the info->params > structure which is at offset 8 from the beginning of info structure, but > code looks at info + 4 instead. This was correct when code was introduced, > but around v2.6.4 three more fields were added to edd_info structure > (commit 66b61a5c in history.git). Second, even if it will check correct > memory it will always succeed since at offset 30 (params->key) there will > be non-zero values otherwise previous check would fail. > > The patch replaces this bogus check with one that verifies checksum. > > Signed-off-by: Gleb Natapov <gleb@redhat.com> > --- > v1->v2 > use device path info length to calculate csum. > > diff --git a/drivers/firmware/edd.c b/drivers/firmware/edd.c > index 96c25d9..f1b7f65 100644 > --- a/drivers/firmware/edd.c > +++ b/drivers/firmware/edd.c > @@ -531,8 +531,8 @@ static int > edd_has_edd30(struct edd_device *edev) > { > struct edd_info *info; > - int i, nonzero_path = 0; > - char c; > + int i; > + u8 csum = 0; > > if (!edev) > return 0; > @@ -544,16 +544,16 @@ edd_has_edd30(struct edd_device *edev) > return 0; > } > > - for (i = 30; i <= 73; i++) { > - c = *(((uint8_t *) info) + i + 4); > - if (c) { > - nonzero_path++; > - break; > - } > - } > - if (!nonzero_path) { > + > + /* We support only T13 spec */ > + if (info->params.device_path_info_length != 44) > + return 0; > + > + for (i = 30; i < info->params.device_path_info_length + 30; i++) > + csum += *(((u8 *)&info->params) + i); > + > + if (csum) > return 0; > - } > > return 1; > } > -- > Gleb. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
-- Gleb.
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