Re: [PATCH] efivarfs: fix abnormal GUID in variable name by usingstrcpy to replace null with dash

[Matt Fleming]

On Fri, 2013-03-01 at 15:17 +0000, Matt Fleming wrote:
> On Fri, 2013-03-01 at 11:20 +0800, Lee, Chun-Yi wrote:
> > From: Michael Schroeder <mls@xxxxxxxx>
> > 
> > On HP z220 system (firmware version 1.54), some EFI variables are incorrectly
> > named :
> > 
> > ls -d /sys/firmware/efi/vars/*8be4d* | grep -v -- -8be returns
> > /sys/firmware/efi/vars/dbxDefault-pport8be4df61-93ca-11d2-aa0d-00e098032b8c
> > /sys/firmware/efi/vars/KEKDefault-pport8be4df61-93ca-11d2-aa0d-00e098032b8c
> > /sys/firmware/efi/vars/SecureBoot-pport8be4df61-93ca-11d2-aa0d-00e098032b8c
> > /sys/firmware/efi/vars/SetupMode-Information8be4df61-93ca-11d2-aa0d-00e098032b8c
> > 
> > That causes by the following statement in efivar_create_sysfs_entry function:
> > 
> >  *(short_name + strlen(short_name)) = '-';
> > efi_guid_unparse(vendor_guid, short_name + strlen(short_name));
> > 
> > The trailing \0 is overwritten with '-', but the next char doesn't seem to be a \0
> > as well for HP. So, the second strlen return the point of next '\0', causes there
> > have garbage string attached before GUID.
> > 
> > Tested on On HP z220.
> 
> What's more likely happening here is that GetNextVariable() is broken on
> this HP firmware and variable_name_size is too big for the given
> variable in variable_name. We've seen other reports of similar bugs,
> 
> 	https://bugzilla.kernel.org/show_bug.cgi?id=47631
> 
> 
> Could someone try this patch against Linus' tree?

Urgh, and here's a version that isn't utterly, utterly broken...

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