On Wed, Apr 10, 2013 at 06:27:13PM +0800, Lingzhu Xiang wrote: > On 04/10/2013 06:45 AM, Ben Hutchings wrote: > >On Mon, 2013-04-08 at 10:50 +0100, Luis Henriques wrote: > >>3.5.7.10 -stable review patch. If anyone has any objections, please let me > >>know. > >> > >>------------------ > >> > >>From: Matt Fleming <matt.flem...@intel.com> > >> > >>commit ec50bd32f1672d38ddce10fb1841cbfda89cfe9a upstream. > >> > >>It's not wise to assume VariableNameSize represents the length of > >>VariableName, as not all firmware updates VariableNameSize in the same > >>way (some don't update it at all if EFI_SUCCESS is returned). There > >>are even implementations out there that update VariableNameSize with > >>values that are both larger than the string returned in VariableName > >>and smaller than the buffer passed to GetNextVariableName(), which > >>resulted in the following bug report from Michael Schroeder, > >> > >> > 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 > >> > >>The issue here is that because we blindly use VariableNameSize without > >>verifying its value, we can potentially read garbage values from the > >>buffer containing VariableName if VariableNameSize is larger than the > >>length of VariableName. > >> > >>Since VariableName is a string, we can calculate its size by searching > >>for the terminating NULL character. > >> > >>Reported-by: Frederic Crozat <fcro...@suse.com> > >>Cc: Matthew Garrett <mj...@srcf.ucam.org> > >>Cc: Josh Boyer <jwbo...@redhat.com> > >>Cc: Michael Schroeder <m...@suse.com> > >>Cc: Lee, Chun-Yi <j...@suse.com> > >>Cc: Lingzhu Xiang <lxi...@redhat.com> > >>Cc: Seiji Aguchi <seiji.agu...@hds.com> > >>Signed-off-by: Matt Fleming <matt.flem...@intel.com> > >>[ Backported for 3.4-stable. Removed workqueue code added in a93bc0c > >>3.9-rc1. ] > >[...] > > > >I thought the workqueue addition was a worthwhile fix in its own right, > >so for 3.2.y I cherry-picked that as well. > > FWIW, the workqueue patch is 1/2 of this patchset[1] fixing closely > related problems. The other one is 81fa4e58. > > [1]: http://article.gmane.org/gmane.linux.kernel/1439570 > > I tried to avoid pulling too much for stable because the patchset is > quite large and I suspect the problem it fixes is only theoretical. > I reported the original bug but was unable to break anything except > getting call traces with various CONFIG_DEBUG_*. > > What's your opinion, Seiji?
Ok, so just to clarify: you're suggesting me to pick the following commits: 81fa4e581d9283f7992a0d8c534bb141eb840a14 efivars: Disable external interrupt while holding efivars->lock a93bc0c6e07ed9bac44700280e65e2945d864fd4 efi_pstore: Introducing workqueue updating sysfs ec50bd32f1672d38ddce10fb1841cbfda89cfe9a efivars: explicitly calculate length of VariableName e971318bbed610e28bb3fde9d548e6aaf0a6b02e efivars: Handle duplicate names from get_next_variable() Is this correct? Cheers, -- Luis -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
