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* efi: split efisubsystem from efivarsTom Gundersen2013-04-171-1794/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This registers /sys/firmware/efi/{,systab,efivars/} whenever EFI is enabled and the system is booted with EFI. This allows *) userspace to check for the existence of /sys/firmware/efi as a way to determine whether or it is running on an EFI system. *) 'mount -t efivarfs none /sys/firmware/efi/efivars' without manually loading any modules. [ Also, move the efivar API into vars.c and unconditionally compile it. This allows us to move efivars.c, which now only contains the sysfs variable code, into the firmware/efi directory. Note that the efivars.c filename is kept to maintain backwards compatability with the old efivars.ko module. With this patch it is now possible for efivarfs to be built without CONFIG_EFI_VARS - Matt ] Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Mike Waychison <mikew@google.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Chun-Yi Lee <jlee@suse.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Tobias Powalowski <tpowa@archlinux.org> Signed-off-by: Tom Gundersen <teg@jklm.no> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivarfs: Move to fs/efivarfsMatt Fleming2013-04-171-496/+0
| | | | | | | | | | | | | | | | | | | | | Now that efivarfs uses the efivar API, move it out of efivars.c and into fs/efivarfs where it belongs. This move will eventually allow us to enable the efivarfs code without having to also enable CONFIG_EFI_VARS built, and vice versa. Furthermore, things like, mount -t efivarfs none /sys/firmware/efi/efivars will now work if efivarfs is built as a module without requiring the use of MODULE_ALIAS(), which would have been necessary when the efivarfs code was part of efivars.c. Cc: Matthew Garrett <matthew.garrett@nebula.com> Cc: Jeremy Kerr <jk@ozlabs.org> Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Move pstore code into the new EFI directoryMatt Fleming2013-04-171-265/+12
| | | | | | | | | | | | | | | | | | | | | efivars.c has grown far too large and needs to be divided up. Create a new directory and move the persistence storage code to efi-pstore.c now that it uses the new efivar API. This helps us to greatly reduce the size of efivars.c and paves the way for moving other code out of efivars.c. Note that because CONFIG_EFI_VARS can be built as a module efi-pstore must also include support for building as a module. Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Anton Vorontsov <cbouatmailru@gmail.com> Cc: Colin Cross <ccross@android.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: efivar_entry APIMatt Fleming2013-04-171-721/+1098
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There isn't really a formal interface for dealing with EFI variables or struct efivar_entry. Historically, this has led to various bits of code directly accessing the generic EFI variable ops, which inherently ties it to specific EFI variable operations instead of indirectly using whatever ops were registered with register_efivars(). This lead to the efivarfs code only working with the generic EFI variable ops and not CONFIG_GOOGLE_SMI. Encapsulate everything that needs to access '__efivars' inside an efivar_entry_* API and use the new API in the pstore, sysfs and efivarfs code. Much of the efivars code had to be rewritten to use this new API. For instance, it is now up to the users of the API to build the initial list of EFI variables in their efivar_init() callback function. The variable list needs to be passed to efivar_init() which allows us to keep work arounds for things like implementation bugs in GetNextVariable() in a central location. Allowing users of the API to use a callback function to build the list greatly benefits the efivarfs code which needs to allocate inodes and dentries for every variable. It previously did this in a racy way because the code ran without holding the variable spinlock. Both the sysfs and efivarfs code maintain their own lists which means the two interfaces can be running simultaneously without interference, though it should be noted that because no synchronisation is performed it is very easy to create inconsistencies. efibootmgr doesn't currently use efivarfs and users are likely to also require the old sysfs interface, so it makes sense to allow both to be built. Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Mike Waychison <mikew@google.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Keep a private global pointer to efivarsMatt Fleming2013-04-171-34/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | Some machines have an EFI variable interface that does not conform to the UEFI specification, e.g. CONFIG_GOOGLE_SMI. Add the necessary code so that it's only possible to use one implementation of EFI variable operations at runtime. This allows us to keep a single (file-scope) global pointer 'struct efivars', which simplifies access. This will hopefully dissuade developers from accessing the generic operations struct directly in the future, as was done in the efivarfs and pstore code, thereby allowing future code to work with both the generic efivar ops and the google SMI ops. This may seem like a step backwards in terms of modularity, but we don't need to track more than one 'struct efivars' at one time. There is no synchronisation done between multiple EFI variable operations, and according to Mike no one is using both the generic EFI var ops and CONFIG_GOOGLE_SMI simultaneously, though a single kernel build _does_ need to able to support both. It also helps to clearly highlight which functions form the core of the efivars interface - those that require access to __efivars. Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Acked-by: Mike Waychison <mikew@google.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efi: move utf16 string functions to efi.hMatt Fleming2013-04-171-17/+0
| | | | | | | | | | | | There are currently two implementations of the utf16 string functions. Somewhat confusingly, they've got different names. Centralise the functions in efi.h. Reviewed-by: Tom Gundersen <teg@jklm.no> Tested-by: Tom Gundersen <teg@jklm.no> Reviewed-by: Mike Waychison <mikew@google.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Fix check for CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLEBen Hutchings2013-03-221-1/+1
| | | | | | | | | The 'CONFIG_' prefix is not implicit in IS_ENABLED(). Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Seth Forshee <seth.forshee@canonical.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Handle duplicate names from get_next_variable()Matt Fleming2013-03-211-1/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some firmware exhibits a bug where the same VariableName and VendorGuid values are returned on multiple invocations of GetNextVariableName(). See, https://bugzilla.kernel.org/show_bug.cgi?id=47631 As a consequence of such a bug, Andre reports hitting the following WARN_ON() in the sysfs code after updating the BIOS on his, "Gigabyte Technology Co., Ltd. To be filled by O.E.M./Z77X-UD3H, BIOS F19e 11/21/2012)" machine, [ 0.581554] EFI Variables Facility v0.08 2004-May-17 [ 0.584914] ------------[ cut here ]------------ [ 0.585639] WARNING: at /home/andre/linux/fs/sysfs/dir.c:536 sysfs_add_one+0xd4/0x100() [ 0.586381] Hardware name: To be filled by O.E.M. [ 0.587123] sysfs: cannot create duplicate filename '/firmware/efi/vars/SbAslBufferPtrVar-01f33c25-764d-43ea-aeea-6b5a41f3f3e8' [ 0.588694] Modules linked in: [ 0.589484] Pid: 1, comm: swapper/0 Not tainted 3.8.0+ #7 [ 0.590280] Call Trace: [ 0.591066] [<ffffffff81208954>] ? sysfs_add_one+0xd4/0x100 [ 0.591861] [<ffffffff810587bf>] warn_slowpath_common+0x7f/0xc0 [ 0.592650] [<ffffffff810588bc>] warn_slowpath_fmt+0x4c/0x50 [ 0.593429] [<ffffffff8134dd85>] ? strlcat+0x65/0x80 [ 0.594203] [<ffffffff81208954>] sysfs_add_one+0xd4/0x100 [ 0.594979] [<ffffffff81208b78>] create_dir+0x78/0xd0 [ 0.595753] [<ffffffff81208ec6>] sysfs_create_dir+0x86/0xe0 [ 0.596532] [<ffffffff81347e4c>] kobject_add_internal+0x9c/0x220 [ 0.597310] [<ffffffff81348307>] kobject_init_and_add+0x67/0x90 [ 0.598083] [<ffffffff81584a71>] ? efivar_create_sysfs_entry+0x61/0x1c0 [ 0.598859] [<ffffffff81584b2b>] efivar_create_sysfs_entry+0x11b/0x1c0 [ 0.599631] [<ffffffff8158517e>] register_efivars+0xde/0x420 [ 0.600395] [<ffffffff81d430a7>] ? edd_init+0x2f5/0x2f5 [ 0.601150] [<ffffffff81d4315f>] efivars_init+0xb8/0x104 [ 0.601903] [<ffffffff8100215a>] do_one_initcall+0x12a/0x180 [ 0.602659] [<ffffffff81d05d80>] kernel_init_freeable+0x13e/0x1c6 [ 0.603418] [<ffffffff81d05586>] ? loglevel+0x31/0x31 [ 0.604183] [<ffffffff816a6530>] ? rest_init+0x80/0x80 [ 0.604936] [<ffffffff816a653e>] kernel_init+0xe/0xf0 [ 0.605681] [<ffffffff816ce7ec>] ret_from_fork+0x7c/0xb0 [ 0.606414] [<ffffffff816a6530>] ? rest_init+0x80/0x80 [ 0.607143] ---[ end trace 1609741ab737eb29 ]--- There's not much we can do to work around and keep traversing the variable list once we hit this firmware bug. Our only solution is to terminate the loop because, as Lingzhu reports, some machines get stuck when they encounter duplicate names, > I had an IBM System x3100 M4 and x3850 X5 on which kernel would > get stuck in infinite loop creating duplicate sysfs files because, > for some reason, there are several duplicate boot entries in nvram > getting GetNextVariableName into a circle of iteration (with > period > 2). Also disable the workqueue, as efivar_update_sysfs_entries() uses GetNextVariableName() to figure out which variables have been created since the last iteration. That algorithm isn't going to work if GetNextVariableName() returns duplicates. Note that we don't disable EFI variable creation completely on the affected machines, it's just that any pstore dump-* files won't appear in sysfs until the next boot. Reported-by: Andre Heider <a.heider@gmail.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Tested-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: explicitly calculate length of VariableNameMatt Fleming2013-03-211-1/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <fcrozat@suse.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Michael Schroeder <mls@suse.com> Cc: Lee, Chun-Yi <jlee@suse.com> Cc: Lingzhu Xiang <lxiang@redhat.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Add module parameter to disable use as a pstore backendSeth Forshee2013-03-211-1/+7
| | | | | | | | | | | | | | | | | | | | | | We know that with some firmware implementations writing too much data to UEFI variables can lead to bricking machines. Recent changes attempt to address this issue, but for some it may still be prudent to avoid writing large amounts of data until the solution has been proven on a wide variety of hardware. Crash dumps or other data from pstore can potentially be a large data source. Add a pstore_module parameter to efivars to allow disabling its use as a backend for pstore. Also add a config option, CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE, to allow setting the default value of this paramter to true (i.e. disabled by default). Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* efivars: Allow disabling use as a pstore backendSeth Forshee2013-03-211-44/+20
| | | | | | | | | | | | | | | | | Add a new option, CONFIG_EFI_VARS_PSTORE, which can be set to N to avoid using efivars as a backend to pstore, as some users may want to compile out the code completely. Set the default to Y to maintain backwards compatability, since this feature has always been enabled until now. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-03-101-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace bugfixes from Eric Biederman: "This is three simple fixes against 3.9-rc1. I have tested each of these fixes and verified they work correctly. The userns oops in key_change_session_keyring and the BUG_ON triggered by proc_ns_follow_link were found by Dave Jones. I am including the enhancement for mount to only trigger requests of filesystem modules here instead of delaying this for the 3.10 merge window because it is both trivial and the kind of change that tends to bit-rot if left untouched for two months." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc: Use nd_jump_link in proc_ns_follow_link fs: Limit sys_mount to only request filesystem modules (Part 2). fs: Limit sys_mount to only request filesystem modules. userns: Stop oopsing in key_change_session_keyring
| * fs: Limit sys_mount to only request filesystem modules.Eric W. Biederman2013-03-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Reported-by: Kees Cook <keescook@google.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | efivarfs: return accurate error code in efivarfs_fill_super()Matt Fleming2013-03-061-5/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Joseph was hitting a failure case when mounting efivarfs which resulted in an incorrect error message, $ sudo mount -v /sys/firmware/efi/efivars mount: Cannot allocate memory triggered when efivarfs_valid_name() returned -EINVAL. Make sure we pass accurate return values up the stack if efivarfs_fill_super() fails to build inodes for EFI variables. Reported-by: Joseph Yasi <joe.yasi@gmail.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: <stable@vger.kernel.org> # v3.8 Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* | efivars: efivarfs_valid_name() should handle pstore syntaxMatt Fleming2013-03-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stricter validation was introduced with commit da27a24383b2b ("efivarfs: guid part of filenames are case-insensitive") and commit 47f531e8ba3b ("efivarfs: Validate filenames much more aggressively"), which is necessary for the guid portion of efivarfs filenames, but we don't need to be so strict with the first part, the variable name. The UEFI specification doesn't impose any constraints on variable names other than they be a NULL-terminated string. The above commits caused a regression that resulted in users seeing the following message, $ sudo mount -v /sys/firmware/efi/efivars mount: Cannot allocate memory whenever pstore EFI variables were present in the variable store, since their variable names failed to pass the following check, /* GUID should be right after the first '-' */ if (s - 1 != strchr(str, '-')) as a typical pstore filename is of the form, dump-type0-10-1-<guid>. The fix is trivial since the guid portion of the filename is GUID_LEN bytes, we can use (len - GUID_LEN) to ensure the '-' character is where we expect it to be. (The bogus ENOMEM error value will be fixed in a separate patch.) Reported-by: Joseph Yasi <joe.yasi@gmail.com> Tested-by: Joseph Yasi <joe.yasi@gmail.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: <stable@vger.kernel.org> # v3.8 Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* | efi: be more paranoid about available space when creating variablesMatthew Garrett2013-03-061-27/+79
|/ | | | | | | | | | | | | | | | | | | UEFI variables are typically stored in flash. For various reasons, avaiable space is typically not reclaimed immediately upon the deletion of a variable - instead, the system will garbage collect during initialisation after a reboot. Some systems appear to handle this garbage collection extremely poorly, failing if more than 50% of the system flash is in use. This can result in the machine refusing to boot. The safest thing to do for the moment is to forbid writes if they'd end up using more than half of the storage space. We can make this more finegrained later if we come up with a method for identifying the broken machines. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* Merge branch 'x86-efi-for-linus' of ↵Linus Torvalds2013-02-281-8/+138
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86/EFI changes from Peter Anvin: - Improve the initrd handling in the EFI boot stub by allowing forward slashes in the pathname - from Chun-Yi Lee. - Cleanup code duplication in the EFI mixed kernel/firmware code - from Satoru Takeuchi. - efivarfs bug fixes for more strict filename validation, with lots of input from Al Viro. * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: remove duplicate code in setup_arch() by using, efi_is_native() efivarfs: guid part of filenames are case-insensitive efivarfs: Validate filenames much more aggressively efivarfs: Use sizeof() instead of magic number x86, efi: Allow slash in file path of initrd
| * efivarfs: guid part of filenames are case-insensitiveMatt Fleming2013-02-121-2/+93
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It makes no sense to treat the following filenames as unique, VarName-abcdefab-abcd-abcd-abcd-abcdefabcdef VarName-ABCDEFAB-ABCD-ABCD-ABCD-ABCDEFABCDEF VarName-ABcDEfAB-ABcD-ABcD-ABcD-ABcDEfABcDEf VarName-aBcDEfAB-aBcD-aBcD-aBcD-aBcDEfaBcDEf ... etc ... since the guid will be converted into a binary representation, which has no case. Roll our own dentry operations so that we can treat the variable name part of filenames ("VarName" in the above example) as case-sensitive, but the guid portion as case-insensitive. That way, efivarfs will refuse to create the above files if any one already exists. Reported-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Validate filenames much more aggressivelyMatt Fleming2013-02-121-5/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only thing that efivarfs does to enforce a valid filename is ensure that the name isn't too short. We need to strongly sanitise any filenames, not least because variable creation is delayed until efivarfs_file_write(), which means we can't rely on the firmware to inform us of an invalid name, because if the file is never written to we'll never know it's invalid. Perform a couple of steps before agreeing to create a new file, * hex_to_bin() returns a value indicating whether or not it was able to convert its arguments to a binary representation - we should check it. * Ensure that the GUID portion of the filename is the correct length and format. * The variable name portion of the filename needs to be at least one character in size. Reported-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Use sizeof() instead of magic numberMatt Fleming2013-01-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Instead of adding a magic 4 to the variable size, use sizeof() to make it explicitly clear what the quantity represents (the variable's attributes). CC: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Chun-Yi Lee <joeyli.kernel@gmail.com> Cc: Andy Whitcroft <apw@canonical.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* | Merge tag 'please-pull-pstore' of ↵Linus Torvalds2013-02-211-47/+133
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux Pull pstore patches from Tony Luck: "A few fixes to reduce places where pstore might hang a system in the crash path. Plus a new mountpoint (/sys/fs/pstore ... makes more sense then /dev/pstore)." Fix up trivial conflict in drivers/firmware/efivars.c * tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux: pstore: Create a convenient mount point for pstore efi_pstore: Introducing workqueue updating sysfs efivars: Disable external interrupt while holding efivars->lock efi_pstore: Avoid deadlock in non-blocking paths pstore: Avoid deadlock in panic and emergency-restart path
| * efi_pstore: Introducing workqueue updating sysfsSeiji Aguchi2013-02-121-5/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Problem] efi_pstore creates sysfs entries, which enable users to access to NVRAM, in a write callback. If a kernel panic happens in an interrupt context, it may fail because it could sleep due to dynamic memory allocations during creating sysfs entries. [Patch Description] This patch removes sysfs operations from a write callback by introducing a workqueue updating sysfs entries which is scheduled after the write callback is called. Also, the workqueue is kicked in a just oops case. A system will go down in other cases such as panic, clean shutdown and emergency restart. And we don't need to create sysfs entries because there is no chance for users to access to them. efi_pstore will be robust against a kernel panic in an interrupt context with this patch. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
| * efivars: Disable external interrupt while holding efivars->lockSeiji Aguchi2013-02-121-42/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Problem] There is a scenario which efi_pstore fails to log messages in a panic case. - CPUA holds an efi_var->lock in either efivarfs parts or efi_pstore with interrupt enabled. - CPUB panics and sends IPI to CPUA in smp_send_stop(). - CPUA stops with holding the lock. - CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC) but it returns without logging messages. [Patch Description] This patch disables an external interruption while holding efivars->lock as follows. In efi_pstore_write() and get_var_data(), spin_lock/spin_unlock is replaced by spin_lock_irqsave/spin_unlock_irqrestore because they may be called in an interrupt context. In other functions, they are replaced by spin_lock_irq/spin_unlock_irq. because they are all called from a process context. By applying this patch, we can avoid the problem above with a following senario. - CPUA holds an efi_var->lock with interrupt disabled. - CPUB panics and sends IPI to CPUA in smp_send_stop(). - CPUA receives the IPI after releasing the lock because it is disabling interrupt while holding the lock. - CPUB waits for one sec until CPUA releases the lock. - CPUB kicks efi_pstore_write() via kmsg_dump(KSMG_DUMP_PANIC) And it can hold the lock successfully. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Mike Waychison <mikew@google.com> Acked-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
| * efi_pstore: Avoid deadlock in non-blocking pathsSeiji Aguchi2013-01-111-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Issue] There is a scenario which efi_pstore may hang up: - cpuA grabs efivars->lock - cpuB panics and calls smp_send_stop - smp_send_stop sends IRQ to cpuA - after 1 second, cpuB gives up on cpuA and sends an NMI instead - cpuA is now in an NMI handler while still holding efivars->lock - cpuB is deadlocked This case may happen if a firmware has a bug and cpuA is stuck talking with it. [Solution] This patch changes a spin_lock to a spin_trylock in non-blocking paths. and if the spin_lock has already taken by another cpu, it returns without accessing to a firmware to avoid the deadlock. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
* | Merge branch 'x86-efi-for-linus' of ↵Linus Torvalds2013-01-311-2/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 EFI fixes from Peter Anvin: "This is a collection of fixes for the EFI support. The controversial bit here is a set of patches which bumps the boot protocol version as part of fixing some serious problems with the EFI handover protocol, used when booting under EFI using a bootloader as opposed to directly from EFI. These changes should also make it a lot saner to support cross-mode 32/64-bit EFI booting in the future. Getting these changes into 3.8 means we avoid presenting an inconsistent ABI to bootloaders. Other changes are display detection and fixing efivarfs." * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: remove attribute check from setup_efi_pci x86, build: Dynamically find entry points in compressed startup code x86, efi: Fix PCI ROM handing in EFI boot stub, in 32-bit mode x86, efi: Fix 32-bit EFI handover protocol entry point x86, efi: Fix display detection in EFI boot stub x86, boot: Define the 2.12 bzImage boot protocol x86/boot: Fix minor fd leakage in tools/relocs.c x86, efi: Set runtime_version to the EFI spec revision x86, efi: fix 32-bit warnings in setup_efi_pci() efivarfs: Delete dentry from dcache in efivarfs_file_write() efivarfs: Never return ENOENT from firmware efi, x86: Pass a proper identity mapping in efi_call_phys_prelog efivarfs: Drop link count of the right inode
| * | efivarfs: Delete dentry from dcache in efivarfs_file_write()Matt Fleming2013-01-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unlike the unlink path that is called from the VFS layer, we need to call d_delete() ourselves when a variable is deleted in efivarfs_file_write(). Failure to do so means we can access a stale struct efivar_entry when reading/writing the file, which can result in the following oops, [ 59.978216] general protection fault: 0000 [#1] SMP [ 60.038660] CPU 9 [ 60.040501] Pid: 1001, comm: cat Not tainted 3.7.0-2.fc19.x86_64 #1 IBM System x3550 M3 -[7944I21]-/69Y4438 [ 60.050840] RIP: 0010:[<ffffffff810d5d1e>] [<ffffffff810d5d1e>] __lock_acquire+0x5e/0x1bb0 [ 60.059198] RSP: 0018:ffff880270595ce8 EFLAGS: 00010046 [ 60.064500] RAX: 0000000000000046 RBX: 0000000000000002 RCX: 0000000000000000 [ 60.071617] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 6b6b6b6b6b6b6b83 [ 60.078735] RBP: ffff880270595dd8 R08: 0000000000000002 R09: 0000000000000000 [ 60.085852] R10: 6b6b6b6b6b6b6b83 R11: 0000000000000000 R12: 0000000000000000 [ 60.092971] R13: ffff88027170cd20 R14: 0000000000000000 R15: 0000000000000000 [ 60.100091] FS: 00007fc0c8ff3740(0000) GS:ffff880277000000(0000) knlGS:0000000000000000 [ 60.108164] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 60.113899] CR2: 0000000001520000 CR3: 000000026d594000 CR4: 00000000000007e0 [ 60.121016] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 60.128135] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 60.135254] Process cat (pid: 1001, threadinfo ffff880270594000, task ffff88027170cd20) [ 60.143239] Stack: [ 60.145251] ffff880270595cf8 ffffffff81021da3 ffff880270595d08 ffffffff81021e19 [ 60.152714] ffff880270595d38 ffffffff810acdb5 ffff880200000168 0000000000000086 [ 60.160175] ffff88027170d5e8 ffffffff810d25ed ffff880270595d58 ffffffff810ace7f [ 60.167638] Call Trace: [ 60.170088] [<ffffffff81021da3>] ? native_sched_clock+0x13/0x80 [ 60.176085] [<ffffffff81021e19>] ? sched_clock+0x9/0x10 [ 60.181389] [<ffffffff810acdb5>] ? sched_clock_cpu+0xc5/0x120 [ 60.187211] [<ffffffff810d25ed>] ? trace_hardirqs_off+0xd/0x10 [ 60.193121] [<ffffffff810ace7f>] ? local_clock+0x6f/0x80 [ 60.198513] [<ffffffff810d2f6f>] ? lock_release_holdtime.part.26+0xf/0x180 [ 60.205465] [<ffffffff810d7b57>] ? lock_release_non_nested+0x2e7/0x320 [ 60.212073] [<ffffffff815638bb>] ? efivarfs_file_write+0x5b/0x280 [ 60.218242] [<ffffffff810d7f41>] lock_acquire+0xa1/0x1f0 [ 60.223633] [<ffffffff81563971>] ? efivarfs_file_write+0x111/0x280 [ 60.229892] [<ffffffff8118b47c>] ? might_fault+0x5c/0xb0 [ 60.235287] [<ffffffff816f1bf6>] _raw_spin_lock+0x46/0x80 [ 60.240762] [<ffffffff81563971>] ? efivarfs_file_write+0x111/0x280 [ 60.247018] [<ffffffff81563971>] efivarfs_file_write+0x111/0x280 [ 60.253103] [<ffffffff811d307f>] vfs_write+0xaf/0x190 [ 60.258233] [<ffffffff811d33d5>] sys_write+0x55/0xa0 [ 60.263278] [<ffffffff816fbd19>] system_call_fastpath+0x16/0x1b [ 60.269271] Code: 41 0f 45 d8 4c 89 75 f0 4c 89 7d f8 85 c0 0f 84 09 01 00 00 8b 05 a3 f9 ff 00 49 89 fa 41 89 f6 41 89 d3 85 c0 0f 84 12 01 00 00 <49> 8b 02 ba 01 00 00 00 48 3d a0 07 14 82 0f 44 da 41 83 fe 01 [ 60.289431] RIP [<ffffffff810d5d1e>] __lock_acquire+0x5e/0x1bb0 [ 60.295444] RSP <ffff880270595ce8> [ 60.298928] ---[ end trace 1bbfd41a2cf6a0d8 ]--- Cc: Josh Boyer <jwboyer@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Lee, Chun-Yi <jlee@suse.com> Cc: Andy Whitcroft <apw@canonical.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * | efivarfs: Never return ENOENT from firmwareMatt Fleming2013-01-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Files are created in efivarfs_create() before a corresponding variable is created in the firmware. This leads to users being able to read/write to the file without the variable existing in the firmware. Reading a non-existent variable currently returns -ENOENT, which is confusing because the file obviously *does* exist. Convert EFI_NOT_FOUND into -EIO which is the closest thing to "error while interacting with firmware", and should hopefully indicate to the caller that the variable is in some uninitialised state. Cc: Josh Boyer <jwboyer@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Lee, Chun-Yi <jlee@suse.com> Cc: Andy Whitcroft <apw@canonical.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * | efivarfs: Drop link count of the right inodeLingzhu Xiang2013-01-181-1/+1
| |/ | | | | | | | | | | | | | | | | efivarfs_unlink() should drop the file's link count, not the directory's. Signed-off-by: Lingzhu Xiang <lxiang@redhat.com> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* / efi: Make 'efi_enabled' a function to query EFI facilitiesMatt Fleming2013-01-301-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Originally 'efi_enabled' indicated whether a kernel was booted from EFI firmware. Over time its semantics have changed, and it now indicates whether or not we are booted on an EFI machine with bit-native firmware, e.g. 64-bit kernel with 64-bit firmware. The immediate motivation for this patch is the bug report at, https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557 which details how running a platform driver on an EFI machine that is designed to run under BIOS can cause the machine to become bricked. Also, the following report, https://bugzilla.kernel.org/show_bug.cgi?id=47121 details how running said driver can also cause Machine Check Exceptions. Drivers need a new means of detecting whether they're running on an EFI machine, as sadly the expression, if (!efi_enabled) hasn't been a sufficient condition for quite some time. Users actually want to query 'efi_enabled' for different reasons - what they really want access to is the list of available EFI facilities. For instance, the x86 reboot code needs to know whether it can invoke the ResetSystem() function provided by the EFI runtime services, while the ACPI OSL code wants to know whether the EFI config tables were mapped successfully. There are also checks in some of the platform driver code to simply see if they're running on an EFI machine (which would make it a bad idea to do BIOS-y things). This patch is a prereq for the samsung-laptop fix patch. Cc: David Airlie <airlied@linux.ie> Cc: Corentin Chary <corentincj@iksaif.net> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Olof Johansson <olof@lixom.net> Cc: Peter Jones <pjones@redhat.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Steve Langasek <steve.langasek@canonical.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* efi: Fix the build with user namespaces enabled.Eric W. Biederman2012-12-181-1/+0
| | | | | | | | | | | | | | | | When compiling efivars.c the build fails with: CC drivers/firmware/efivars.o drivers/firmware/efivars.c: In function ‘efivarfs_get_inode’: drivers/firmware/efivars.c:886:31: error: incompatible types when assigning to type ‘kgid_t’ from type ‘int’ make[2]: *** [drivers/firmware/efivars.o] Error 1 make[1]: *** [drivers/firmware/efivars.o] Error 2 Fix the build error by removing the duplicate initialization of i_uid and i_gid inode_init_always has already initialized them to 0. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'core-efi-for-linus' of ↵Linus Torvalds2012-12-141-8/+504
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 EFI update from Peter Anvin: "EFI tree, from Matt Fleming. Most of the patches are the new efivarfs filesystem by Matt Garrett & co. The balance are support for EFI wallclock in the absence of a hardware-specific driver, and various fixes and cleanups." * 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) efivarfs: Make efivarfs_fill_super() static x86, efi: Check table header length in efi_bgrt_init() efivarfs: Use query_variable_info() to limit kmalloc() efivarfs: Fix return value of efivarfs_file_write() efivarfs: Return a consistent error when efivarfs_get_inode() fails efivarfs: Make 'datasize' unsigned long efivarfs: Add unique magic number efivarfs: Replace magic number with sizeof(attributes) efivarfs: Return an error if we fail to read a variable efi: Clarify GUID length calculations efivarfs: Implement exclusive access for {get,set}_variable efivarfs: efivarfs_fill_super() ensure we clean up correctly on error efivarfs: efivarfs_fill_super() ensure we free our temporary name efivarfs: efivarfs_fill_super() fix inode reference counts efivarfs: efivarfs_create() ensure we drop our reference on inode on error efivarfs: efivarfs_file_read ensure we free data in error paths x86-64/efi: Use EFI to deal with platform wall clock (again) x86/kernel: remove tboot 1:1 page table creation code x86, efi: 1:1 pagetable mapping for virtual EFI calls x86, mm: Include the entire kernel memory map in trampoline_pgd ...
| * efivarfs: Make efivarfs_fill_super() staticMatt Fleming2012-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | sparse is complaining that efivarfs_fill_super() doesn't have a prototype. Make it static to avoid the warning. Cc: Xie ChanglongX <changlongx.xie@intel.com> Cc: Matthew Garrett <mjg@redhat.com> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Use query_variable_info() to limit kmalloc()Matt Fleming2012-11-131-9/+34
| | | | | | | | | | | | | | | | | | | | | | We don't want someone who can write EFI variables to be able to allocate arbitrarily large amounts of memory, so cap it to something sensible like the amount of free space for EFI variables. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Matthew Garrett <mjg@redhat.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Fix return value of efivarfs_file_write()Matt Fleming2012-10-301-5/+8
| | | | | | | | | | | | | | | | | | | | We're stuffing a variable of type size_t (unsigned) into a ssize_t (signed) which, even though both types should be the same number of bits, it's just asking for sign issues to be introduced. Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Return a consistent error when efivarfs_get_inode() failsMatt Fleming2012-10-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | Instead of returning -ENOSPC if efivarfs_get_inode() fails we should be returning -ENOMEM, since running out of memory is the only reason it can fail. Furthermore, that's the error value used everywhere else in this file. It's also less likely to confuse users that hit this error case. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Make 'datasize' unsigned longMatt Fleming2012-10-301-1/+1
| | | | | | | | | | | | | | | | | | There's no reason to declare 'datasize' as an int, since the majority of the functions it's passed to expect an unsigned long anyway. Plus, this way we avoid any sign problems during arithmetic. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Add unique magic numberMatt Fleming2012-10-301-1/+1
| | | | | | | | | | | | | | | | Using pstore's superblock magic number is no doubt going to cause problems in the future. Give efivarfs its own magic number. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Replace magic number with sizeof(attributes)Matt Fleming2012-10-301-4/+4
| | | | | | | | | | | | | | | | | | Seeing "+ 4" littered throughout the functions gets a bit confusing. Use "sizeof(attributes)" which clearly explains what quantity we're adding. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Return an error if we fail to read a variableMatt Fleming2012-10-301-26/+36
| | | | | | | | | | | | | | | | | | | | Instead of always returning 0 in efivarfs_file_read(), even when we fail to successfully read the variable, convert the EFI status to something meaningful and return that to the caller. This way the user will have some hint as to why the read failed. Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efi: Clarify GUID length calculationsJeremy Kerr2012-10-301-8/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At present, the handling of GUIDs in efivar file names isn't consistent. We use GUID_LEN in some places, and 38 in others (GUID_LEN plus separator), and implicitly use the presence of the trailing NUL. This change removes the trailing NUL from GUID_LEN, so that we're explicitly adding it when required. We also replace magic numbers with GUID_LEN, and clarify the comments where appropriate. We also fix the allocation size in efivar_create_sysfs_entry, where we're allocating one byte too much, due to counting the trailing NUL twice - once when calculating short_name_size, and once in the kzalloc. Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: Implement exclusive access for {get,set}_variableJeremy Kerr2012-10-301-25/+43
| | | | | | | | | | | | | | | | | | | | | | | | Currently, efivarfs does not enforce exclusion over the get_variable and set_variable operations. Section 7.1 of UEFI requires us to only allow a single processor to enter {get,set}_variable services at once. This change acquires the efivars->lock over calls to these operations from the efivarfs paths. Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: efivarfs_fill_super() ensure we clean up correctly on errorAndy Whitcroft2012-10-301-2/+18
| | | | | | | | | | | | | | | | | | | | Ensure we free both the name and inode on error when building the individual variables. Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: efivarfs_fill_super() ensure we free our temporary nameAndy Whitcroft2012-10-301-0/+2
| | | | | | | | | | | | | | | | | | | | d_alloc_name() copies the passed name to new storage, once complete we no longer need our name. Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: efivarfs_fill_super() fix inode reference countsAndy Whitcroft2012-10-301-12/+4
| | | | | | | | | | | | | | | | | | | | When d_make_root() fails it will automatically drop the reference on the root inode. We should not be doing so as well. Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: efivarfs_create() ensure we drop our reference on inode on errorAndy Whitcroft2012-10-301-5/+9
| | | | | | | | | | | | | | Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efivarfs: efivarfs_file_read ensure we free data in error pathsAndy Whitcroft2012-10-301-3/+3
| | | | | | | | | | | | | | Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Matthew Garrett <mjg@redhat.com> Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efi: add efivars kobject to efi sysfs folderLee, Chun-Yi2012-10-301-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | UEFI variable filesystem need a new mount point, so this patch add efivars kobject to efi_kobj for create a /sys/firmware/efi/efivars folder. Cc: Matthew Garrett <mjg@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efi: Handle deletions and size changes in efivarfs_write_fileJeremy Kerr2012-10-301-10/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A write to an efivarfs file will not always result in a variable of 'count' size after the EFI SetVariable() call. We may have appended to the existing data (ie, with the EFI_VARIABLE_APPEND_WRITE attribute), or even have deleted the variable (with an authenticated variable update, with a zero datasize). This change re-reads the updated variable from firmware, to check for size changes and deletions. In the latter case, we need to drop the dentry. Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| * efi: Add support for a UEFI variable filesystemMatthew Garrett2012-10-301-6/+378
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The existing EFI variables code only supports variables of up to 1024 bytes. This limitation existed in version 0.99 of the EFI specification, but was removed before any full releases. Since variables can now be larger than a single page, sysfs isn't the best interface for this. So, instead, let's add a filesystem. Variables can be read, written and created, with the first 4 bytes of each variable representing its UEFI attributes. The create() method doesn't actually commit to flash since zero-length variables can't exist per-spec. Updates from Jeremy Kerr <jeremy.kerr@canonical.com>. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
* | efi_pstore: Add a format check for an existing variable name at erasing timeSeiji Aguchi2012-11-271-2/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Issue] a format of variable name has been updated to type, id, count and ctime to support holding multiple logs. Format of current variable name dump-type0-1-2-12345678 type:0 id:1 count:2 ctime:12345678 On the other hand, if an old variable name before being updated remains, users can't erase it via /dev/pstore. Format of old variable name dump-type0-1-12345678 type:0 id:1 ctime:12345678 [Solution] This patch add a format check for the old variable name in a erase callback to make it erasable. Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Mike Waychison <mikew@google.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
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