| Message ID | 1560459027-5248-3-git-send-email-nayna@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | powerpc/powernv: expose secure variables to userspace | expand |
On Thu, Jun 13, 2019 at 04:50:27PM -0400, Nayna Jain wrote: > As part of PowerNV secure boot support, OS verification keys are stored > and controlled by OPAL as secure variables. These need to be exposed to > the userspace so that sysadmins can perform key management tasks. > > This patch adds the support to expose secure variables via a sysfs > interface It reuses the the existing efi defined hooks and backend in > order to maintain the compatibility with the userspace tools. > > Though it reuses a great deal of efi, POWER platforms do not use EFI. > A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs > interface. > > Signed-off-by: Nayna Jain <nayna@linux.ibm.com> > --- > arch/powerpc/Kconfig | 2 + > drivers/firmware/Makefile | 1 + > drivers/firmware/efi/efivars.c | 2 +- > drivers/firmware/powerpc/Kconfig | 12 + > drivers/firmware/powerpc/Makefile | 3 + > drivers/firmware/powerpc/efi_error.c | 46 ++++ > drivers/firmware/powerpc/secvar.c | 326 +++++++++++++++++++++++++++ > 7 files changed, 391 insertions(+), 1 deletion(-) > create mode 100644 drivers/firmware/powerpc/Kconfig > create mode 100644 drivers/firmware/powerpc/Makefile > create mode 100644 drivers/firmware/powerpc/efi_error.c > create mode 100644 drivers/firmware/powerpc/secvar.c If you add/remove/modify sysfs files, you also need to update the relevant Documentation/ABI/ entry as well. Please add something there to describe your new files when you resend the next version of this patch series. > diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig > new file mode 100644 > index 000000000000..e0303fc517d5 > --- /dev/null > +++ b/drivers/firmware/powerpc/Kconfig > @@ -0,0 +1,12 @@ > +config POWER_SECVAR_SYSFS > + tristate "Enable sysfs interface for POWER secure variables" > + default n default is always n, no need to list it. > --- /dev/null > +++ b/drivers/firmware/powerpc/efi_error.c > @@ -0,0 +1,46 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 IBM Corporation > + * Author: Nayna Jain <nayna@linux.ibm.com> > + * > + * efi_error.c > + * - Error codes as understood by efi based tools > + * Taken from drivers/firmware/efi/efi.c Why not just export the symbol from the original file instead of duplicating it here? > +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid) > +{ > + u32 *a1; > + u16 *a2; > + u16 *a3; > + > + a1 = kzalloc(4, GFP_KERNEL); No error checking in this function for memory issues at all? > + memcpy(a1, buffer, 4); > + *a1 = be32_to_cpu(*a1); > + > + a2 = kzalloc(2, GFP_KERNEL); > + memcpy(a2, buffer+4, 2); > + *a2 = be16_to_cpu(*a2); > + > + a3 = kzalloc(2, GFP_KERNEL); > + memcpy(a3, buffer+6, 2); > + *a3 = be16_to_cpu(*a3); > + > + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8), > + *(buffer + 9), > + *(buffer + 10), > + *(buffer + 11), > + *(buffer + 12), > + *(buffer + 13), > + *(buffer + 14), > + *(buffer + 15)); > + > + kfree(a1); > + kfree(a2); > + kfree(a3); > + return 0; > +} > +static efi_status_t powerpc_get_next_variable(unsigned long *name_size, > + efi_char16_t *name, > + efi_guid_t *vendor) > +{ > + int rc; > + u8 *key; > + int namesize; > + unsigned long keylen; > + unsigned long keysize = 1024; > + unsigned long *mdsize; > + u8 *mdata = NULL; > + efi_guid_t guid; > + > + if (ucs2_strnlen(name, 1024) > 0) { > + createkey(name, &key, &keylen); > + } else { > + keylen = 0; > + key = kzalloc(1024, GFP_KERNEL); > + } > + > + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key); Don't put debugging info like this in the kernel log of everyone :( > + > + rc = opal_get_next_variable(key, &keylen, keysize); > + if (rc) { > + kfree(key); > + return opal_to_efi_status(rc); > + } > + > + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL); No error checking? > + rc = opal_get_variable_size(key, keylen, mdsize, NULL); > + if (rc) > + goto out; > + > + if (*mdsize <= 0) > + goto out; > + > + mdata = kzalloc(*mdsize, GFP_KERNEL); > + > + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL); > + if (rc) > + goto out; > + > + if (*mdsize > 0) { > + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32); > + if (namesize > 0) { > + memset(&guid, 0, sizeof(efi_guid_t)); > + convert_buffer_to_efi_guid(mdata + namesize, &guid); > + memcpy(vendor, &guid, sizeof(efi_guid_t)); > + memset(name, 0, namesize + 2); > + memcpy(name, mdata, namesize); > + *name_size = namesize + 2; > + name[namesize++] = 0; > + name[namesize] = 0; > + } > + } > + > +out: > + kfree(mdsize); > + kfree(mdata); > + > + return opal_to_efi_status(rc); > +} > + > +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor, > + u32 attr, unsigned long data_size, > + void *data) > +{ > + int rc; > + u8 *key; > + unsigned long keylen; > + u8 *metadata; > + unsigned long mdsize; > + > + if (!name) > + return EFI_INVALID_PARAMETER; > + > + if (!vendor) > + return EFI_INVALID_PARAMETER; > + > + createkey(name, &key, &keylen); > + pr_info("%s: nayna key is %s\n", __func__, key); Again, please remove all of your debugging code when resending. > + > + createmetadata(name, vendor, &attr, &metadata, &mdsize); > + > + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size); > + > + return opal_to_efi_status(rc); > +} > + > + > +static const struct efivar_operations efivar_ops = { > + .get_variable = powerpc_get_variable, > + .set_variable = powerpc_set_variable, > + .get_next_variable = powerpc_get_next_variable, > +}; > + > + > +static __init int power_secvar_init(void) > +{ > + int rc = 0; > + unsigned long ver = 0; > + > + rc = opal_variable_version(&ver); > + if (ver != BACKEND_TC_COMPAT_V1) { > + pr_info("Compatible backend unsupported\n"); > + return -1; Do not make up error numbers, use the defined values please. thanks, greg k-h
On 06/14/2019 02:34 AM, Greg Kroah-Hartman wrote: > On Thu, Jun 13, 2019 at 04:50:27PM -0400, Nayna Jain wrote: >> As part of PowerNV secure boot support, OS verification keys are stored >> and controlled by OPAL as secure variables. These need to be exposed to >> the userspace so that sysadmins can perform key management tasks. >> >> This patch adds the support to expose secure variables via a sysfs >> interface It reuses the the existing efi defined hooks and backend in >> order to maintain the compatibility with the userspace tools. >> >> Though it reuses a great deal of efi, POWER platforms do not use EFI. >> A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs >> interface. >> >> Signed-off-by: Nayna Jain <nayna@linux.ibm.com> >> --- >> arch/powerpc/Kconfig | 2 + >> drivers/firmware/Makefile | 1 + >> drivers/firmware/efi/efivars.c | 2 +- >> drivers/firmware/powerpc/Kconfig | 12 + >> drivers/firmware/powerpc/Makefile | 3 + >> drivers/firmware/powerpc/efi_error.c | 46 ++++ >> drivers/firmware/powerpc/secvar.c | 326 +++++++++++++++++++++++++++ >> 7 files changed, 391 insertions(+), 1 deletion(-) >> create mode 100644 drivers/firmware/powerpc/Kconfig >> create mode 100644 drivers/firmware/powerpc/Makefile >> create mode 100644 drivers/firmware/powerpc/efi_error.c >> create mode 100644 drivers/firmware/powerpc/secvar.c > If you add/remove/modify sysfs files, you also need to update the > relevant Documentation/ABI/ entry as well. Please add something there > to describe your new files when you resend the next version of this > patch series. > >> diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig >> new file mode 100644 >> index 000000000000..e0303fc517d5 >> --- /dev/null >> +++ b/drivers/firmware/powerpc/Kconfig >> @@ -0,0 +1,12 @@ >> +config POWER_SECVAR_SYSFS >> + tristate "Enable sysfs interface for POWER secure variables" >> + default n > default is always n, no need to list it. > >> --- /dev/null >> +++ b/drivers/firmware/powerpc/efi_error.c >> @@ -0,0 +1,46 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (C) 2019 IBM Corporation >> + * Author: Nayna Jain <nayna@linux.ibm.com> >> + * >> + * efi_error.c >> + * - Error codes as understood by efi based tools >> + * Taken from drivers/firmware/efi/efi.c > Why not just export the symbol from the original file instead of > duplicating it here? > >> +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid) >> +{ >> + u32 *a1; >> + u16 *a2; >> + u16 *a3; >> + >> + a1 = kzalloc(4, GFP_KERNEL); > No error checking in this function for memory issues at all? > >> + memcpy(a1, buffer, 4); >> + *a1 = be32_to_cpu(*a1); >> + >> + a2 = kzalloc(2, GFP_KERNEL); >> + memcpy(a2, buffer+4, 2); >> + *a2 = be16_to_cpu(*a2); >> + >> + a3 = kzalloc(2, GFP_KERNEL); >> + memcpy(a3, buffer+6, 2); >> + *a3 = be16_to_cpu(*a3); >> + >> + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8), >> + *(buffer + 9), >> + *(buffer + 10), >> + *(buffer + 11), >> + *(buffer + 12), >> + *(buffer + 13), >> + *(buffer + 14), >> + *(buffer + 15)); >> + >> + kfree(a1); >> + kfree(a2); >> + kfree(a3); >> + return 0; >> +} >> +static efi_status_t powerpc_get_next_variable(unsigned long *name_size, >> + efi_char16_t *name, >> + efi_guid_t *vendor) >> +{ >> + int rc; >> + u8 *key; >> + int namesize; >> + unsigned long keylen; >> + unsigned long keysize = 1024; >> + unsigned long *mdsize; >> + u8 *mdata = NULL; >> + efi_guid_t guid; >> + >> + if (ucs2_strnlen(name, 1024) > 0) { >> + createkey(name, &key, &keylen); >> + } else { >> + keylen = 0; >> + key = kzalloc(1024, GFP_KERNEL); >> + } >> + >> + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key); > Don't put debugging info like this in the kernel log of everyone :( > >> + >> + rc = opal_get_next_variable(key, &keylen, keysize); >> + if (rc) { >> + kfree(key); >> + return opal_to_efi_status(rc); >> + } >> + >> + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL); > No error checking? > >> + rc = opal_get_variable_size(key, keylen, mdsize, NULL); >> + if (rc) >> + goto out; >> + >> + if (*mdsize <= 0) >> + goto out; >> + >> + mdata = kzalloc(*mdsize, GFP_KERNEL); >> + >> + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL); >> + if (rc) >> + goto out; >> + >> + if (*mdsize > 0) { >> + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32); >> + if (namesize > 0) { >> + memset(&guid, 0, sizeof(efi_guid_t)); >> + convert_buffer_to_efi_guid(mdata + namesize, &guid); >> + memcpy(vendor, &guid, sizeof(efi_guid_t)); >> + memset(name, 0, namesize + 2); >> + memcpy(name, mdata, namesize); >> + *name_size = namesize + 2; >> + name[namesize++] = 0; >> + name[namesize] = 0; >> + } >> + } >> + >> +out: >> + kfree(mdsize); >> + kfree(mdata); >> + >> + return opal_to_efi_status(rc); >> +} >> + >> +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor, >> + u32 attr, unsigned long data_size, >> + void *data) >> +{ >> + int rc; >> + u8 *key; >> + unsigned long keylen; >> + u8 *metadata; >> + unsigned long mdsize; >> + >> + if (!name) >> + return EFI_INVALID_PARAMETER; >> + >> + if (!vendor) >> + return EFI_INVALID_PARAMETER; >> + >> + createkey(name, &key, &keylen); >> + pr_info("%s: nayna key is %s\n", __func__, key); > Again, please remove all of your debugging code when resending. > >> + >> + createmetadata(name, vendor, &attr, &metadata, &mdsize); >> + >> + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size); >> + >> + return opal_to_efi_status(rc); >> +} >> + >> + >> +static const struct efivar_operations efivar_ops = { >> + .get_variable = powerpc_get_variable, >> + .set_variable = powerpc_set_variable, >> + .get_next_variable = powerpc_get_next_variable, >> +}; >> + >> + >> +static __init int power_secvar_init(void) >> +{ >> + int rc = 0; >> + unsigned long ver = 0; >> + >> + rc = opal_variable_version(&ver); >> + if (ver != BACKEND_TC_COMPAT_V1) { >> + pr_info("Compatible backend unsupported\n"); >> + return -1; > Do not make up error numbers, use the defined values please. Thanks Greg for the review !! I will address everything in the next version. Thanks & Regards, - Nayna
Hi Nayna, Nayna Jain <nayna@linux.ibm.com> writes: > As part of PowerNV secure boot support, OS verification keys are stored > and controlled by OPAL as secure variables. These need to be exposed to > the userspace so that sysadmins can perform key management tasks. > > This patch adds the support to expose secure variables via a sysfs > interface It reuses the the existing efi defined hooks and backend in > order to maintain the compatibility with the userspace tools. Which tools? Can you include a log demonstrating how they're used, ie. so that I can test the sequence of commands. > Though it reuses a great deal of efi, POWER platforms do not use EFI. > A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs > interface. Sorry I haven't been able to keep up with all the discussions, but I thought the consensus was that pretending to be EFI-like was a bad idea, because we don't have actual EFI and we're not implementing an entirely compatible scheme to EFI anyway. Greg suggested just putting the variables in sysfs, why does that not work? Matthew mentioned "complex semantics around variable deletion and immutability" but do we have to emulate those semantics on powerpc? cheers > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 9de77bb14f54..1548dd8cf1a0 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -916,6 +916,8 @@ config PPC_SECURE_BOOT > allows user to enable OS Secure Boot on PowerPC systems that > have firmware secure boot support. > > +source "drivers/firmware/powerpc/Kconfig" > + > endmenu > > config ISA_DMA_API > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile > index 3fa0b34eb72f..8cfaf7e6769d 100644 > --- a/drivers/firmware/Makefile > +++ b/drivers/firmware/Makefile > @@ -33,3 +33,4 @@ obj-$(CONFIG_UEFI_CPER) += efi/ > obj-y += imx/ > obj-y += tegra/ > obj-y += xilinx/ > +obj-$(CONFIG_POWER_SECVAR_SYSFS) += powerpc/ > diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c > index 7576450c8254..30ef53003c24 100644 > --- a/drivers/firmware/efi/efivars.c > +++ b/drivers/firmware/efi/efivars.c > @@ -664,7 +664,7 @@ int efivars_sysfs_init(void) > struct kobject *parent_kobj = efivars_kobject(); > int error = 0; > > - if (!efi_enabled(EFI_RUNTIME_SERVICES)) > + if (IS_ENABLED(CONFIG_EFI) && !efi_enabled(EFI_RUNTIME_SERVICES)) > return -ENODEV; > > /* No efivars has been registered yet */ > diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig > new file mode 100644 > index 000000000000..e0303fc517d5 > --- /dev/null > +++ b/drivers/firmware/powerpc/Kconfig > @@ -0,0 +1,12 @@ > +config POWER_SECVAR_SYSFS > + tristate "Enable sysfs interface for POWER secure variables" > + default n > + depends on PPC_SECURE_BOOT > + select UCS2_STRING > + help > + POWER secure variables are managed and controlled by OPAL. > + These variables are exposed to userspace via sysfs to allow > + user to read/write these variables. Say Y if you have secure > + boot enabled and want to expose variables to userspace. > + > +source "drivers/firmware/efi/Kconfig" > diff --git a/drivers/firmware/powerpc/Makefile b/drivers/firmware/powerpc/Makefile > new file mode 100644 > index 000000000000..d5fa3b007315 > --- /dev/null > +++ b/drivers/firmware/powerpc/Makefile > @@ -0,0 +1,3 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +obj-$(CONFIG_POWER_SECVAR_SYSFS) += ../efi/efivars.o efi_error.o ../efi/vars.o secvar.o > diff --git a/drivers/firmware/powerpc/efi_error.c b/drivers/firmware/powerpc/efi_error.c > new file mode 100644 > index 000000000000..b5cabd52e6b4 > --- /dev/null > +++ b/drivers/firmware/powerpc/efi_error.c > @@ -0,0 +1,46 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 IBM Corporation > + * Author: Nayna Jain <nayna@linux.ibm.com> > + * > + * efi_error.c > + * - Error codes as understood by efi based tools > + * Taken from drivers/firmware/efi/efi.c > + */ > +#include<linux/efi.h> > + > +int efi_status_to_err(efi_status_t status) > +{ > + int err; > + > + switch (status) { > + case EFI_SUCCESS: > + err = 0; > + break; > + case EFI_INVALID_PARAMETER: > + err = -EINVAL; > + break; > + case EFI_OUT_OF_RESOURCES: > + err = -ENOSPC; > + break; > + case EFI_DEVICE_ERROR: > + err = -EIO; > + break; > + case EFI_WRITE_PROTECTED: > + err = -EROFS; > + break; > + case EFI_SECURITY_VIOLATION: > + err = -EACCES; > + break; > + case EFI_NOT_FOUND: > + err = -ENOENT; > + break; > + case EFI_ABORTED: > + err = -EINTR; > + break; > + default: > + err = -EINVAL; > + } > + > + return err; > +} > diff --git a/drivers/firmware/powerpc/secvar.c b/drivers/firmware/powerpc/secvar.c > new file mode 100644 > index 000000000000..f1f134a0bb7c > --- /dev/null > +++ b/drivers/firmware/powerpc/secvar.c > @@ -0,0 +1,326 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 IBM Corporation > + * Author: Nayna Jain <nayna@linux.ibm.com> > + * > + * secvar.c > + * - wrappers to expose secure variables to userspace > + */ > +#include <linux/kernel.h> > +#include <linux/init.h> > +#include <linux/types.h> > +#include <linux/errno.h> > +#include <linux/string.h> > +#include <linux/spinlock.h> > +#include <linux/fs.h> > +#include <linux/slab.h> > +#include <linux/ioctl.h> > +#include <linux/uaccess.h> > +#include <linux/kdebug.h> > +#include <linux/efi.h> > +#include <linux/module.h> > +#include <linux/ucs2_string.h> > +#include <asm/opal-secvar.h> > +#include <asm/opal.h> > + > +static struct efivars efivars; > +struct kobject *powerpc_kobj; > + > +efi_status_t opal_to_efi_status_log(int rc, const char *func_name) > +{ > + efi_status_t status; > + > + switch (rc) { > + case OPAL_EMPTY: > + status = EFI_NOT_FOUND; > + break; > + case OPAL_HARDWARE: > + status = EFI_DEVICE_ERROR; > + break; > + case OPAL_NO_MEM: > + pr_err("%s: No space in the volatile storage\n", func_name); > + status = EFI_OUT_OF_RESOURCES; > + break; > + case OPAL_PARAMETER: > + status = EFI_INVALID_PARAMETER; > + break; > + case OPAL_PARTIAL: > + status = EFI_BUFFER_TOO_SMALL; > + break; > + case OPAL_PERMISSION: > + status = EFI_WRITE_PROTECTED; > + break; > + case OPAL_RESOURCE: > + pr_err("%s: No space in the non-volatile storage\n", func_name); > + status = EFI_OUT_OF_RESOURCES; > + break; > + case OPAL_SUCCESS: > + status = EFI_SUCCESS; > + break; > + default: > + pr_err("%s: Unknown OPAL error %d\n", func_name, rc); > + status = EFI_DEVICE_ERROR; > + break; > + } > + > + return status; > +} > + > +#define opal_to_efi_status(rc) opal_to_efi_status_log(rc, __func__) > + > +static void createkey(efi_char16_t *name, u8 **key, unsigned long *keylen) > +{ > + *keylen = ucs2_utf8size(name) + 1; > + > + *key = kzalloc(*keylen, GFP_KERNEL); > + if (!*key) { > + *keylen = 0; > + *key = NULL; > + return; > + } > + > + ucs2_as_utf8(*key, name, *keylen); > +} > + > +static void createmetadata(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, > + u8 **mdata, unsigned long *mdsize) > +{ > + int size = 0; > + > + *mdsize = ucs2_strsize(name, 1024) + sizeof(efi_guid_t) + sizeof(u32); > + *mdata = kzalloc(*mdsize, GFP_KERNEL); > + > + memcpy(*mdata, name, ucs2_strsize(name, 1024)); > + size = ucs2_strsize(name, 1024); > + > + memcpy(*mdata + size, vendor, sizeof(efi_guid_t)); > + size += sizeof(efi_guid_t); > + > + if (attr != NULL) > + memcpy(*mdata + size, attr, sizeof(u32)); > + else > + memset(*mdata + size, 0, sizeof(u32)); > +} > + > +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid) > +{ > + u32 *a1; > + u16 *a2; > + u16 *a3; > + > + a1 = kzalloc(4, GFP_KERNEL); > + memcpy(a1, buffer, 4); > + *a1 = be32_to_cpu(*a1); > + > + a2 = kzalloc(2, GFP_KERNEL); > + memcpy(a2, buffer+4, 2); > + *a2 = be16_to_cpu(*a2); > + > + a3 = kzalloc(2, GFP_KERNEL); > + memcpy(a3, buffer+6, 2); > + *a3 = be16_to_cpu(*a3); > + > + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8), > + *(buffer + 9), > + *(buffer + 10), > + *(buffer + 11), > + *(buffer + 12), > + *(buffer + 13), > + *(buffer + 14), > + *(buffer + 15)); > + > + kfree(a1); > + kfree(a2); > + kfree(a3); > + return 0; > +} > + > +static efi_status_t powerpc_get_variable(efi_char16_t *name, efi_guid_t *vendor, > + u32 *attr, unsigned long *data_size, > + void *data) > +{ > + int rc; > + u8 *key; > + unsigned long keylen; > + u8 *metadata; > + unsigned long mdsize; > + unsigned long dsize; > + unsigned long namesize; > + > + if (!name) > + return EFI_INVALID_PARAMETER; > + > + if (!vendor) > + return EFI_INVALID_PARAMETER; > + > + if (*data_size == 0) { > + /* If *data_size is zero, it implies data size is being asked */ > + createkey(name, &key, &keylen); > + rc = opal_get_variable_size(key, keylen, &mdsize, &dsize); > + *data_size = dsize; > + kfree(key); > + return opal_to_efi_status(rc); > + } > + > + createkey(name, &key, &keylen); > + createmetadata(name, vendor, attr, &metadata, &mdsize); > + > + rc = opal_get_variable(key, keylen, metadata, &mdsize, data, data_size); > + > + if (rc) > + return opal_to_efi_status(rc); > + > + if (mdsize > 0) { > + namesize = mdsize - sizeof(efi_guid_t) - sizeof(u32); > + if (!attr) > + return opal_to_efi_status(rc); > + memset(attr, 0, sizeof(u32)); > + memcpy(attr, metadata + namesize + sizeof(efi_guid_t), > + sizeof(u32)); > + *attr = be32_to_cpu(*attr); > + } > + > + kfree(key); > + kfree(metadata); > + > + return opal_to_efi_status(rc); > +} > + > + > +static efi_status_t powerpc_get_next_variable(unsigned long *name_size, > + efi_char16_t *name, > + efi_guid_t *vendor) > +{ > + int rc; > + u8 *key; > + int namesize; > + unsigned long keylen; > + unsigned long keysize = 1024; > + unsigned long *mdsize; > + u8 *mdata = NULL; > + efi_guid_t guid; > + > + if (ucs2_strnlen(name, 1024) > 0) { > + createkey(name, &key, &keylen); > + } else { > + keylen = 0; > + key = kzalloc(1024, GFP_KERNEL); > + } > + > + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key); > + > + rc = opal_get_next_variable(key, &keylen, keysize); > + if (rc) { > + kfree(key); > + return opal_to_efi_status(rc); > + } > + > + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL); > + rc = opal_get_variable_size(key, keylen, mdsize, NULL); > + if (rc) > + goto out; > + > + if (*mdsize <= 0) > + goto out; > + > + mdata = kzalloc(*mdsize, GFP_KERNEL); > + > + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL); > + if (rc) > + goto out; > + > + if (*mdsize > 0) { > + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32); > + if (namesize > 0) { > + memset(&guid, 0, sizeof(efi_guid_t)); > + convert_buffer_to_efi_guid(mdata + namesize, &guid); > + memcpy(vendor, &guid, sizeof(efi_guid_t)); > + memset(name, 0, namesize + 2); > + memcpy(name, mdata, namesize); > + *name_size = namesize + 2; > + name[namesize++] = 0; > + name[namesize] = 0; > + } > + } > + > +out: > + kfree(mdsize); > + kfree(mdata); > + > + return opal_to_efi_status(rc); > +} > + > +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor, > + u32 attr, unsigned long data_size, > + void *data) > +{ > + int rc; > + u8 *key; > + unsigned long keylen; > + u8 *metadata; > + unsigned long mdsize; > + > + if (!name) > + return EFI_INVALID_PARAMETER; > + > + if (!vendor) > + return EFI_INVALID_PARAMETER; > + > + createkey(name, &key, &keylen); > + pr_info("%s: nayna key is %s\n", __func__, key); > + > + createmetadata(name, vendor, &attr, &metadata, &mdsize); > + > + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size); > + > + return opal_to_efi_status(rc); > +} > + > + > +static const struct efivar_operations efivar_ops = { > + .get_variable = powerpc_get_variable, > + .set_variable = powerpc_set_variable, > + .get_next_variable = powerpc_get_next_variable, > +}; > + > + > +static __init int power_secvar_init(void) > +{ > + int rc = 0; > + unsigned long ver = 0; > + > + rc = opal_variable_version(&ver); > + if (ver != BACKEND_TC_COMPAT_V1) { > + pr_info("Compatible backend unsupported\n"); > + return -1; > + } > + > + powerpc_kobj = kobject_create_and_add("secvar", firmware_kobj); > + if (!powerpc_kobj) { > + pr_info("secvar: Failed to create firmware kobj\n"); > + goto out_err; > + } > + > + rc = efivars_register(&efivars, &efivar_ops, powerpc_kobj); > + if (rc) { > + pr_info("powerpc: Failed to register efivars\n"); > + return rc; > + } > + > + return 0; > +out_err: > + kobject_put(powerpc_kobj); > + pr_info("powerpc: failed to load: %d\n", rc); > + return rc; > +} > +arch_initcall(power_secvar_init); > + > +static void __exit power_secvar_exit(void) > +{ > + efivars_unregister(&efivars); > + kobject_put(powerpc_kobj); > +} > +module_exit(power_secvar_exit); > + > +MODULE_AUTHOR("Nayna Jain"); > +MODULE_LICENSE("GPL"); > -- > 2.20.1
On Thu, 2019-06-13 at 16:50 -0400, Nayna Jain wrote: > As part of PowerNV secure boot support, OS verification keys are stored > and controlled by OPAL as secure variables. These need to be exposed to > the userspace so that sysadmins can perform key management tasks. > > This patch adds the support to expose secure variables via a sysfs > interface It reuses the the existing efi defined hooks and backend in > order to maintain the compatibility with the userspace tools. > > Though it reuses a great deal of efi, POWER platforms do not use EFI. > A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs > interface. I spent all day staring at the skiboot bits of this, so I figured I should see what the kernel bits looked like too... On the last version of this patch set (posted by Claudio) Matthew Garret was pretty explicit about the interface here not conforming to the expectations of efivars[1], so what's changed in this patch set to fix that? As far as I can tell it's has the same basic problems as before, just with a slightly different OPAL interface. [1] https://www.spinics.net/lists/linux-efi/msg15897.html > > Signed-off-by: Nayna Jain <nayna@linux.ibm.com> > --- > arch/powerpc/Kconfig | 2 + > drivers/firmware/Makefile | 1 + > drivers/firmware/efi/efivars.c | 2 +- > drivers/firmware/powerpc/Kconfig | 12 + > drivers/firmware/powerpc/Makefile | 3 + > drivers/firmware/powerpc/efi_error.c | 46 ++++ > drivers/firmware/powerpc/secvar.c | 326 +++++++++++++++++++++++++++ > 7 files changed, 391 insertions(+), 1 deletion(-) > create mode 100644 drivers/firmware/powerpc/Kconfig > create mode 100644 drivers/firmware/powerpc/Makefile > create mode 100644 drivers/firmware/powerpc/efi_error.c > create mode 100644 drivers/firmware/powerpc/secvar.c > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 9de77bb14f54..1548dd8cf1a0 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -916,6 +916,8 @@ config PPC_SECURE_BOOT > allows user to enable OS Secure Boot on PowerPC systems that > have firmware secure boot support. > > +source "drivers/firmware/powerpc/Kconfig" > + > endmenu All of this is *very* powernv specific, so why is it here and not in arch/powerpc/platforms/powernv/ with the rest of the powernv platform code? Also, nothing about this is generic to powerpc as a whole so the Kconfig symbol should probably be change the Kconfig symbol to POWERNV_SECURE_BOOT or OPAL_SECURE_BOOT > config ISA_DMA_API > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile > index 3fa0b34eb72f..8cfaf7e6769d 100644 > --- a/drivers/firmware/Makefile > +++ b/drivers/firmware/Makefile > @@ -33,3 +33,4 @@ obj-$(CONFIG_UEFI_CPER) += efi/ > obj-y += imx/ > obj-y += tegra/ > obj-y += xilinx/ > +obj-$(CONFIG_POWER_SECVAR_SYSFS) += powerpc/ > diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c > index 7576450c8254..30ef53003c24 100644 > --- a/drivers/firmware/efi/efivars.c > +++ b/drivers/firmware/efi/efivars.c > @@ -664,7 +664,7 @@ int efivars_sysfs_init(void) > struct kobject *parent_kobj = efivars_kobject(); > int error = 0; > > - if (!efi_enabled(EFI_RUNTIME_SERVICES)) > + if (IS_ENABLED(CONFIG_EFI) && !efi_enabled(EFI_RUNTIME_SERVICES)) > return -ENODEV; > > /* No efivars has been registered yet */ Seems a bit sketch. > diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig > new file mode 100644 > index 000000000000..e0303fc517d5 > --- /dev/null > +++ b/drivers/firmware/powerpc/Kconfig > @@ -0,0 +1,12 @@ > +config POWER_SECVAR_SYSFS > + tristate "Enable sysfs interface for POWER secure variables" > + default n > + depends on PPC_SECURE_BOOT > + select UCS2_STRING > + help > + POWER secure variables are managed and controlled by OPAL. > + These variables are exposed to userspace via sysfs to allow > + user to read/write these variables. Say Y if you have secure > + boot enabled and want to expose variables to userspace. > + > +source "drivers/firmware/efi/Kconfig" Again, this is all powernv specific and not generic to all powerpc platforms. > diff --git a/drivers/firmware/powerpc/Makefile b/drivers/firmware/powerpc/Makefile > new file mode 100644 > index 000000000000..d5fa3b007315 > --- /dev/null > +++ b/drivers/firmware/powerpc/Makefile > @@ -0,0 +1,3 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +obj-$(CONFIG_POWER_SECVAR_SYSFS) += ../efi/efivars.o efi_error.o ../efi/vars.o secvar.o Uh... That is going to need an Ack from someone in EFI land. > diff --git a/drivers/firmware/powerpc/efi_error.c b/drivers/firmware/powerpc/efi_error.c > new file mode 100644 > index 000000000000..b5cabd52e6b4 > --- /dev/null > +++ b/drivers/firmware/powerpc/efi_error.c > @@ -0,0 +1,46 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 IBM Corporation > + * Author: Nayna Jain <nayna@linux.ibm.com> > + * > + * efi_error.c > + * - Error codes as understood by efi based tools > + * Taken from drivers/firmware/efi/efi.c > + */ > +#include<linux/efi.h> > + > +int efi_status_to_err(efi_status_t status) > +{ > + int err; > + > + switch (status) { > + case EFI_SUCCESS: > + err = 0; > + break; > + case EFI_INVALID_PARAMETER: > + err = -EINVAL; > + break; > + case EFI_OUT_OF_RESOURCES: > + err = -ENOSPC; > + break; > + case EFI_DEVICE_ERROR: > + err = -EIO; > + break; > + case EFI_WRITE_PROTECTED: > + err = -EROFS; > + break; > + case EFI_SECURITY_VIOLATION: > + err = -EACCES; > + break; > + case EFI_NOT_FOUND: > + err = -ENOENT; > + break; > + case EFI_ABORTED: > + err = -EINTR; > + break; > + default: > + err = -EINVAL; > + } > + > + return err; > +} what calls this? > diff --git a/drivers/firmware/powerpc/secvar.c b/drivers/firmware/powerpc/secvar.c > new file mode 100644 > index 000000000000..f1f134a0bb7c > --- /dev/null > +++ b/drivers/firmware/powerpc/secvar.c > @@ -0,0 +1,326 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 IBM Corporation > + * Author: Nayna Jain <nayna@linux.ibm.com> > + * > + * secvar.c > + * - wrappers to expose secure variables to userspace > + */ > +#include <linux/kernel.h> > +#include <linux/init.h> > +#include <linux/types.h> > +#include <linux/errno.h> > +#include <linux/string.h> > +#include <linux/spinlock.h> > +#include <linux/fs.h> > +#include <linux/slab.h> > +#include <linux/ioctl.h> > +#include <linux/uaccess.h> > +#include <linux/kdebug.h> > +#include <linux/efi.h> > +#include <linux/module.h> > +#include <linux/ucs2_string.h> > +#include <asm/opal-secvar.h> > +#include <asm/opal.h> > + > +static struct efivars efivars; > +struct kobject *powerpc_kobj; > + > +efi_status_t opal_to_efi_status_log(int rc, const char *func_name) > +{ > + efi_status_t status; > + > + switch (rc) { > + case OPAL_EMPTY: > + status = EFI_NOT_FOUND; > + break; > + case OPAL_HARDWARE: > + status = EFI_DEVICE_ERROR; > + break; > + case OPAL_NO_MEM: > + pr_err("%s: No space in the volatile storage\n", func_name); > + status = EFI_OUT_OF_RESOURCES; > + break; > + case OPAL_PARAMETER: > + status = EFI_INVALID_PARAMETER; > + break; > + case OPAL_PARTIAL: > + status = EFI_BUFFER_TOO_SMALL; > + break; > + case OPAL_PERMISSION: > + status = EFI_WRITE_PROTECTED; > + break; > + case OPAL_RESOURCE: > + pr_err("%s: No space in the non-volatile storage\n", func_name); > + status = EFI_OUT_OF_RESOURCES; > + break; > + case OPAL_SUCCESS: > + status = EFI_SUCCESS; > + break; > + default: > + pr_err("%s: Unknown OPAL error %d\n", func_name, rc); > + status = EFI_DEVICE_ERROR; > + break; > + } > + > + return status; > +} > + > +#define opal_to_efi_status(rc) opal_to_efi_status_log(rc, __func__) > + > +static void createkey(efi_char16_t *name, u8 **key, unsigned long *keylen) > +{ > + *keylen = ucs2_utf8size(name) + 1; > + > + *key = kzalloc(*keylen, GFP_KERNEL); > + if (!*key) { > + *keylen = 0; > + *key = NULL; > + return; > + } > + > + ucs2_as_utf8(*key, name, *keylen); > +} > > +static void createmetadata(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, > + u8 **mdata, unsigned long *mdsize) > +{ > + int size = 0; > + > + *mdsize = ucs2_strsize(name, 1024) + sizeof(efi_guid_t) + sizeof(u32); > + *mdata = kzalloc(*mdsize, GFP_KERNEL); > + > + memcpy(*mdata, name, ucs2_strsize(name, 1024)); > + size = ucs2_strsize(name, 1024); > + > + memcpy(*mdata + size, vendor, sizeof(efi_guid_t)); > + size += sizeof(efi_guid_t); > + > + if (attr != NULL) > + memcpy(*mdata + size, attr, sizeof(u32)); > + else > + memset(*mdata + size, 0, sizeof(u32)); > +} > +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid) > +{ > + u32 *a1; > + u16 *a2; > + u16 *a3; > + > + a1 = kzalloc(4, GFP_KERNEL); > + memcpy(a1, buffer, 4); > + *a1 = be32_to_cpu(*a1); > + > + a2 = kzalloc(2, GFP_KERNEL); > + memcpy(a2, buffer+4, 2); > + *a2 = be16_to_cpu(*a2); > + > + a3 = kzalloc(2, GFP_KERNEL); > + memcpy(a3, buffer+6, 2); > + *a3 = be16_to_cpu(*a3); > + > + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8), > + *(buffer + 9), > + *(buffer + 10), > + *(buffer + 11), > + *(buffer + 12), > + *(buffer + 13), > + *(buffer + 14), > + *(buffer + 15)); > + > + kfree(a1); > + kfree(a2); > + kfree(a3); These should be on the stack, They're small and you free them almost immediately after allocating them. > + return 0; > +} > +static efi_status_t powerpc_get_variable(efi_char16_t *name, efi_guid_t *vendor, > + u32 *attr, unsigned long *data_size, > + void *data) > +{ > + int rc; > + u8 *key; > + unsigned long keylen; > + u8 *metadata; > + unsigned long mdsize; > + unsigned long dsize; > + unsigned long namesize; > + > + if (!name) > + return EFI_INVALID_PARAMETER; > + > + if (!vendor) > + return EFI_INVALID_PARAMETER; > + > + if (*data_size == 0) { > + /* If *data_size is zero, it implies data size is being asked */ > + createkey(name, &key, &keylen); > + rc = opal_get_variable_size(key, keylen, &mdsize, &dsize); > + *data_size = dsize; > + kfree(key); > + return opal_to_efi_status(rc); > + } > + > + createkey(name, &key, &keylen); > + createmetadata(name, vendor, attr, &metadata, &mdsize); > + > + rc = opal_get_variable(key, keylen, metadata, &mdsize, data, data_size); > + > + if (rc) > + return opal_to_efi_status(rc); > + > + if (mdsize > 0) { > + namesize = mdsize - sizeof(efi_guid_t) - sizeof(u32); > + if (!attr) > + return opal_to_efi_status(rc); > + memset(attr, 0, sizeof(u32)); > + memcpy(attr, metadata + namesize + sizeof(efi_guid_t), > + sizeof(u32)); > + *attr = be32_to_cpu(*attr); > + } > + > + kfree(key); > + kfree(metadata); > + > + return opal_to_efi_status(rc); > +} > + > + > +static efi_status_t powerpc_get_next_variable(unsigned long *name_size, > + efi_char16_t *name, > + efi_guid_t *vendor) > +{ > + int rc; > + u8 *key; > + int namesize; > + unsigned long keylen; > + unsigned long keysize = 1024; > + unsigned long *mdsize; > + u8 *mdata = NULL; > + efi_guid_t guid; > + > + if (ucs2_strnlen(name, 1024) > 0) { > + createkey(name, &key, &keylen); > + } else { > + keylen = 0; > + key = kzalloc(1024, GFP_KERNEL); > + } > + > + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key); > + > + rc = opal_get_next_variable(key, &keylen, keysize); As far as I can tell the UEFI spec says the key namespace is really made up of (vendor, key) tuples. This seems broken to me since it's ignoring the vendor GUID part and treating it purely as an output, so if we had two vendors (OS vendors maybe?) writing using the same key name it'll cause problems. You could fix that by concatenating the vendor GUID and the ucs-2 name string, then passing that to OPAL as the key. Based on what the gsmi driver does I don't think we really need to store the attributes either so the metadata channel can be ditched entirely. > + if (rc) { > + kfree(key); > + return opal_to_efi_status(rc); > + } > + > + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL); > + rc = opal_get_variable_size(key, keylen, mdsize, NULL); > + if (rc) > + goto out; > + > + if (*mdsize <= 0) > + goto out; > + > + mdata = kzalloc(*mdsize, GFP_KERNEL); > + > + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL); > + if (rc) > + goto out; > + > + if (*mdsize > 0) { > + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32); > + if (namesize > 0) { > + memset(&guid, 0, sizeof(efi_guid_t)); > + convert_buffer_to_efi_guid(mdata + namesize, &guid); > + memcpy(vendor, &guid, sizeof(efi_guid_t)); > + memset(name, 0, namesize + 2); > + memcpy(name, mdata, namesize); > + *name_size = namesize + 2; > + name[namesize++] = 0; > + name[namesize] = 0; > + } > + } > + > +out: > + kfree(mdsize); > + kfree(mdata); > + > + return opal_to_efi_status(rc); > +} > + > +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor, > + u32 attr, unsigned long data_size, > + void *data) > +{ > + int rc; > + u8 *key; > + unsigned long keylen; > + u8 *metadata; > + unsigned long mdsize; > + > + if (!name) > + return EFI_INVALID_PARAMETER; > + > + if (!vendor) > + return EFI_INVALID_PARAMETER; > + > + createkey(name, &key, &keylen); > + pr_info("%s: nayna key is %s\n", __func__, key); > + > + createmetadata(name, vendor, &attr, &metadata, &mdsize); > + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size); > + > + return opal_to_efi_status(rc); > +} > + > + > +static const struct efivar_operations efivar_ops = { > + .get_variable = powerpc_get_variable, > + .set_variable = powerpc_set_variable, > + .get_next_variable = powerpc_get_next_variable, > +}; > + > + > +static __init int power_secvar_init(void) > +{ > + int rc = 0; > + unsigned long ver = 0; > + > + rc = opal_variable_version(&ver); > + if (ver != BACKEND_TC_COMPAT_V1) { > + pr_info("Compatible backend unsupported\n"); > + return -1; > + } > + > + powerpc_kobj = kobject_create_and_add("secvar", firmware_kobj); > + if (!powerpc_kobj) { > + pr_info("secvar: Failed to create firmware kobj\n"); > + goto out_err; > + } > + > + rc = efivars_register(&efivars, &efivar_ops, powerpc_kobj); > + if (rc) { > + pr_info("powerpc: Failed to register efivars\n"); > + return rc; > + } > + > + return 0; > +out_err: > + kobject_put(powerpc_kobj); > + pr_info("powerpc: failed to load: %d\n", rc); > + return rc; > +} > +arch_initcall(power_secvar_init); > + > +static void __exit power_secvar_exit(void) > +{ > + efivars_unregister(&efivars); > + kobject_put(powerpc_kobj); > +} > +module_exit(power_secvar_exit); > + > +MODULE_AUTHOR("Nayna Jain"); > +MODULE_LICENSE("GPL");
On 07/05/2019 02:05 AM, Michael Ellerman wrote: > Hi Nayna, Hi Michael, Oliver, > > Nayna Jain <nayna@linux.ibm.com> writes: >> As part of PowerNV secure boot support, OS verification keys are stored >> and controlled by OPAL as secure variables. These need to be exposed to >> the userspace so that sysadmins can perform key management tasks. >> >> This patch adds the support to expose secure variables via a sysfs >> interface It reuses the the existing efi defined hooks and backend in >> order to maintain the compatibility with the userspace tools. > Which tools? Can you include a log demonstrating how they're used, ie. > so that I can test the sequence of commands. > >> Though it reuses a great deal of efi, POWER platforms do not use EFI. >> A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs >> interface. > Sorry I haven't been able to keep up with all the discussions, but I > thought the consensus was that pretending to be EFI-like was a bad idea, > because we don't have actual EFI and we're not implementing an entirely > compatible scheme to EFI anyway. > > Greg suggested just putting the variables in sysfs, why does that not > work? Matthew mentioned "complex semantics around variable deletion and > immutability" but do we have to emulate those semantics on powerpc? Sorry for the delay in the response. Yes, I agree. The purpose of the v2 version of the patchset was to try and quickly address Matthew's concerns. This version of the patchset: * is not using any EFI configs * is not exposing secure variables via efivarfs * is based on Greg's suggestion to use sysfs * is STILL using some of the existing EFI code, that is used by EFI to expose its variables via sysfs, to avoid code duplication. * is using efivar hooks to expose secure variables for tool compatibility Assuming we all are in agreement, the next version of this patchset will further improve upon these changes. It will refactor some of the sysfs code from drivers/firmware/efi that is common to both EFI and POWER. Since we do not have to emulate the complex semantics of efi on powerpc, the sysfs interface should work for us. As per the tool, it will be efivar. I will provide the log demonstrating how it is used with the next version. Is there something I missed in my understanding ? Thanks & Regards, - Nayna
On Wed, Jul 24, 2019 at 12:35 AM Nayna <nayna@linux.vnet.ibm.com> wrote: > > On 07/05/2019 02:05 AM, Michael Ellerman wrote: > > Hi Nayna, > > Hi Michael, Oliver, > > > Nayna Jain <nayna@linux.ibm.com> writes: > >> As part of PowerNV secure boot support, OS verification keys are stored > >> and controlled by OPAL as secure variables. These need to be exposed to > >> the userspace so that sysadmins can perform key management tasks. > >> > >> This patch adds the support to expose secure variables via a sysfs > >> interface It reuses the the existing efi defined hooks and backend in > >> order to maintain the compatibility with the userspace tools. > > Which tools? Can you include a log demonstrating how they're used, ie. > > so that I can test the sequence of commands. > > > >> Though it reuses a great deal of efi, POWER platforms do not use EFI. > >> A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs > >> interface. > > Sorry I haven't been able to keep up with all the discussions, but I > > thought the consensus was that pretending to be EFI-like was a bad idea, > > because we don't have actual EFI and we're not implementing an entirely > > compatible scheme to EFI anyway. My read is the consensus was that pretending to be EFI is a bad idea unless we're going to behave like EFI. > > Greg suggested just putting the variables in sysfs, why does that not > > work? Matthew mentioned "complex semantics around variable deletion and > > immutability" but do we have to emulate those semantics on powerpc? > > Sorry for the delay in the response. > > Yes, I agree. The purpose of the v2 version of the patchset was to try > and quickly address Matthew's concerns. This version of the patchset: > * is based on Greg's suggestion to use sysfs As far as I can tell Greg made that suggestion here: https://lwn.net/ml/linux-fsdevel/20190603072916.GA7545@kroah.com/ Then walked back on that suggestion after Matthew pointed out that efivars is separate because of the immutability requirement and the odd update semantics: https://lwn.net/ml/linux-fsdevel/20190605081301.GA23180@kroah.com/ Considering the whole point of this is to present the same user-facing interface so shouldn't you be dealing with all the problems that interface creates? > * is not using any EFI configs That's true, but... > * is not exposing secure variables via efivarfs > * is STILL using some of the existing EFI code, that is used by EFI to > expose its variables via sysfs, to avoid code duplication. We avoid some of the potential problems of selecting CONFIG_EFI and we gain a bunch of other potential problems since you've hacked the makefiles to build code that's normally CONFIG_EFI only. > * is using efivar hooks to expose secure variables for tool compatibility Here's the real problem. For compatibility with the existing userspace tooling, which expects UEFI, you need to present the same interface with the same semantics. Trying to not use efivarfs means you've already lost since you no longer have the same interface. So how is this an improvement? I think the options here are to either: 1) Come up with a new interface, implement it, and adapt the user tooling to deal with the new API. *or* 2) Use efivarsfs and fix the based i-cant-believe-its-not-efi variable backend so it behaves *exactly* like the UEFI get/setVariable APIs. This means that you need to validate the update certificates at runtime. I don't think this is a huge strech since you're already implementing the validator. 1) gives you the flexibility to change the key hierarchy and whatnot, while 2) means we've got less weird powerpc crap for users to deal with. I have no strong opinions about which you choose to do, but don't do this. Oliver
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 9de77bb14f54..1548dd8cf1a0 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -916,6 +916,8 @@ config PPC_SECURE_BOOT allows user to enable OS Secure Boot on PowerPC systems that have firmware secure boot support. +source "drivers/firmware/powerpc/Kconfig" + endmenu config ISA_DMA_API diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index 3fa0b34eb72f..8cfaf7e6769d 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -33,3 +33,4 @@ obj-$(CONFIG_UEFI_CPER) += efi/ obj-y += imx/ obj-y += tegra/ obj-y += xilinx/ +obj-$(CONFIG_POWER_SECVAR_SYSFS) += powerpc/ diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c index 7576450c8254..30ef53003c24 100644 --- a/drivers/firmware/efi/efivars.c +++ b/drivers/firmware/efi/efivars.c @@ -664,7 +664,7 @@ int efivars_sysfs_init(void) struct kobject *parent_kobj = efivars_kobject(); int error = 0; - if (!efi_enabled(EFI_RUNTIME_SERVICES)) + if (IS_ENABLED(CONFIG_EFI) && !efi_enabled(EFI_RUNTIME_SERVICES)) return -ENODEV; /* No efivars has been registered yet */ diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig new file mode 100644 index 000000000000..e0303fc517d5 --- /dev/null +++ b/drivers/firmware/powerpc/Kconfig @@ -0,0 +1,12 @@ +config POWER_SECVAR_SYSFS + tristate "Enable sysfs interface for POWER secure variables" + default n + depends on PPC_SECURE_BOOT + select UCS2_STRING + help + POWER secure variables are managed and controlled by OPAL. + These variables are exposed to userspace via sysfs to allow + user to read/write these variables. Say Y if you have secure + boot enabled and want to expose variables to userspace. + +source "drivers/firmware/efi/Kconfig" diff --git a/drivers/firmware/powerpc/Makefile b/drivers/firmware/powerpc/Makefile new file mode 100644 index 000000000000..d5fa3b007315 --- /dev/null +++ b/drivers/firmware/powerpc/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-$(CONFIG_POWER_SECVAR_SYSFS) += ../efi/efivars.o efi_error.o ../efi/vars.o secvar.o diff --git a/drivers/firmware/powerpc/efi_error.c b/drivers/firmware/powerpc/efi_error.c new file mode 100644 index 000000000000..b5cabd52e6b4 --- /dev/null +++ b/drivers/firmware/powerpc/efi_error.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain <nayna@linux.ibm.com> + * + * efi_error.c + * - Error codes as understood by efi based tools + * Taken from drivers/firmware/efi/efi.c + */ +#include<linux/efi.h> + +int efi_status_to_err(efi_status_t status) +{ + int err; + + switch (status) { + case EFI_SUCCESS: + err = 0; + break; + case EFI_INVALID_PARAMETER: + err = -EINVAL; + break; + case EFI_OUT_OF_RESOURCES: + err = -ENOSPC; + break; + case EFI_DEVICE_ERROR: + err = -EIO; + break; + case EFI_WRITE_PROTECTED: + err = -EROFS; + break; + case EFI_SECURITY_VIOLATION: + err = -EACCES; + break; + case EFI_NOT_FOUND: + err = -ENOENT; + break; + case EFI_ABORTED: + err = -EINTR; + break; + default: + err = -EINVAL; + } + + return err; +} diff --git a/drivers/firmware/powerpc/secvar.c b/drivers/firmware/powerpc/secvar.c new file mode 100644 index 000000000000..f1f134a0bb7c --- /dev/null +++ b/drivers/firmware/powerpc/secvar.c @@ -0,0 +1,326 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain <nayna@linux.ibm.com> + * + * secvar.c + * - wrappers to expose secure variables to userspace + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/spinlock.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/ioctl.h> +#include <linux/uaccess.h> +#include <linux/kdebug.h> +#include <linux/efi.h> +#include <linux/module.h> +#include <linux/ucs2_string.h> +#include <asm/opal-secvar.h> +#include <asm/opal.h> + +static struct efivars efivars; +struct kobject *powerpc_kobj; + +efi_status_t opal_to_efi_status_log(int rc, const char *func_name) +{ + efi_status_t status; + + switch (rc) { + case OPAL_EMPTY: + status = EFI_NOT_FOUND; + break; + case OPAL_HARDWARE: + status = EFI_DEVICE_ERROR; + break; + case OPAL_NO_MEM: + pr_err("%s: No space in the volatile storage\n", func_name); + status = EFI_OUT_OF_RESOURCES; + break; + case OPAL_PARAMETER: + status = EFI_INVALID_PARAMETER; + break; + case OPAL_PARTIAL: + status = EFI_BUFFER_TOO_SMALL; + break; + case OPAL_PERMISSION: + status = EFI_WRITE_PROTECTED; + break; + case OPAL_RESOURCE: + pr_err("%s: No space in the non-volatile storage\n", func_name); + status = EFI_OUT_OF_RESOURCES; + break; + case OPAL_SUCCESS: + status = EFI_SUCCESS; + break; + default: + pr_err("%s: Unknown OPAL error %d\n", func_name, rc); + status = EFI_DEVICE_ERROR; + break; + } + + return status; +} + +#define opal_to_efi_status(rc) opal_to_efi_status_log(rc, __func__) + +static void createkey(efi_char16_t *name, u8 **key, unsigned long *keylen) +{ + *keylen = ucs2_utf8size(name) + 1; + + *key = kzalloc(*keylen, GFP_KERNEL); + if (!*key) { + *keylen = 0; + *key = NULL; + return; + } + + ucs2_as_utf8(*key, name, *keylen); +} + +static void createmetadata(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, + u8 **mdata, unsigned long *mdsize) +{ + int size = 0; + + *mdsize = ucs2_strsize(name, 1024) + sizeof(efi_guid_t) + sizeof(u32); + *mdata = kzalloc(*mdsize, GFP_KERNEL); + + memcpy(*mdata, name, ucs2_strsize(name, 1024)); + size = ucs2_strsize(name, 1024); + + memcpy(*mdata + size, vendor, sizeof(efi_guid_t)); + size += sizeof(efi_guid_t); + + if (attr != NULL) + memcpy(*mdata + size, attr, sizeof(u32)); + else + memset(*mdata + size, 0, sizeof(u32)); +} + +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid) +{ + u32 *a1; + u16 *a2; + u16 *a3; + + a1 = kzalloc(4, GFP_KERNEL); + memcpy(a1, buffer, 4); + *a1 = be32_to_cpu(*a1); + + a2 = kzalloc(2, GFP_KERNEL); + memcpy(a2, buffer+4, 2); + *a2 = be16_to_cpu(*a2); + + a3 = kzalloc(2, GFP_KERNEL); + memcpy(a3, buffer+6, 2); + *a3 = be16_to_cpu(*a3); + + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8), + *(buffer + 9), + *(buffer + 10), + *(buffer + 11), + *(buffer + 12), + *(buffer + 13), + *(buffer + 14), + *(buffer + 15)); + + kfree(a1); + kfree(a2); + kfree(a3); + return 0; +} + +static efi_status_t powerpc_get_variable(efi_char16_t *name, efi_guid_t *vendor, + u32 *attr, unsigned long *data_size, + void *data) +{ + int rc; + u8 *key; + unsigned long keylen; + u8 *metadata; + unsigned long mdsize; + unsigned long dsize; + unsigned long namesize; + + if (!name) + return EFI_INVALID_PARAMETER; + + if (!vendor) + return EFI_INVALID_PARAMETER; + + if (*data_size == 0) { + /* If *data_size is zero, it implies data size is being asked */ + createkey(name, &key, &keylen); + rc = opal_get_variable_size(key, keylen, &mdsize, &dsize); + *data_size = dsize; + kfree(key); + return opal_to_efi_status(rc); + } + + createkey(name, &key, &keylen); + createmetadata(name, vendor, attr, &metadata, &mdsize); + + rc = opal_get_variable(key, keylen, metadata, &mdsize, data, data_size); + + if (rc) + return opal_to_efi_status(rc); + + if (mdsize > 0) { + namesize = mdsize - sizeof(efi_guid_t) - sizeof(u32); + if (!attr) + return opal_to_efi_status(rc); + memset(attr, 0, sizeof(u32)); + memcpy(attr, metadata + namesize + sizeof(efi_guid_t), + sizeof(u32)); + *attr = be32_to_cpu(*attr); + } + + kfree(key); + kfree(metadata); + + return opal_to_efi_status(rc); +} + + +static efi_status_t powerpc_get_next_variable(unsigned long *name_size, + efi_char16_t *name, + efi_guid_t *vendor) +{ + int rc; + u8 *key; + int namesize; + unsigned long keylen; + unsigned long keysize = 1024; + unsigned long *mdsize; + u8 *mdata = NULL; + efi_guid_t guid; + + if (ucs2_strnlen(name, 1024) > 0) { + createkey(name, &key, &keylen); + } else { + keylen = 0; + key = kzalloc(1024, GFP_KERNEL); + } + + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key); + + rc = opal_get_next_variable(key, &keylen, keysize); + if (rc) { + kfree(key); + return opal_to_efi_status(rc); + } + + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL); + rc = opal_get_variable_size(key, keylen, mdsize, NULL); + if (rc) + goto out; + + if (*mdsize <= 0) + goto out; + + mdata = kzalloc(*mdsize, GFP_KERNEL); + + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL); + if (rc) + goto out; + + if (*mdsize > 0) { + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32); + if (namesize > 0) { + memset(&guid, 0, sizeof(efi_guid_t)); + convert_buffer_to_efi_guid(mdata + namesize, &guid); + memcpy(vendor, &guid, sizeof(efi_guid_t)); + memset(name, 0, namesize + 2); + memcpy(name, mdata, namesize); + *name_size = namesize + 2; + name[namesize++] = 0; + name[namesize] = 0; + } + } + +out: + kfree(mdsize); + kfree(mdata); + + return opal_to_efi_status(rc); +} + +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor, + u32 attr, unsigned long data_size, + void *data) +{ + int rc; + u8 *key; + unsigned long keylen; + u8 *metadata; + unsigned long mdsize; + + if (!name) + return EFI_INVALID_PARAMETER; + + if (!vendor) + return EFI_INVALID_PARAMETER; + + createkey(name, &key, &keylen); + pr_info("%s: nayna key is %s\n", __func__, key); + + createmetadata(name, vendor, &attr, &metadata, &mdsize); + + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size); + + return opal_to_efi_status(rc); +} + + +static const struct efivar_operations efivar_ops = { + .get_variable = powerpc_get_variable, + .set_variable = powerpc_set_variable, + .get_next_variable = powerpc_get_next_variable, +}; + + +static __init int power_secvar_init(void) +{ + int rc = 0; + unsigned long ver = 0; + + rc = opal_variable_version(&ver); + if (ver != BACKEND_TC_COMPAT_V1) { + pr_info("Compatible backend unsupported\n"); + return -1; + } + + powerpc_kobj = kobject_create_and_add("secvar", firmware_kobj); + if (!powerpc_kobj) { + pr_info("secvar: Failed to create firmware kobj\n"); + goto out_err; + } + + rc = efivars_register(&efivars, &efivar_ops, powerpc_kobj); + if (rc) { + pr_info("powerpc: Failed to register efivars\n"); + return rc; + } + + return 0; +out_err: + kobject_put(powerpc_kobj); + pr_info("powerpc: failed to load: %d\n", rc); + return rc; +} +arch_initcall(power_secvar_init); + +static void __exit power_secvar_exit(void) +{ + efivars_unregister(&efivars); + kobject_put(powerpc_kobj); +} +module_exit(power_secvar_exit); + +MODULE_AUTHOR("Nayna Jain"); +MODULE_LICENSE("GPL");
As part of PowerNV secure boot support, OS verification keys are stored and controlled by OPAL as secure variables. These need to be exposed to the userspace so that sysadmins can perform key management tasks. This patch adds the support to expose secure variables via a sysfs interface It reuses the the existing efi defined hooks and backend in order to maintain the compatibility with the userspace tools. Though it reuses a great deal of efi, POWER platforms do not use EFI. A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs interface. Signed-off-by: Nayna Jain <nayna@linux.ibm.com> --- arch/powerpc/Kconfig | 2 + drivers/firmware/Makefile | 1 + drivers/firmware/efi/efivars.c | 2 +- drivers/firmware/powerpc/Kconfig | 12 + drivers/firmware/powerpc/Makefile | 3 + drivers/firmware/powerpc/efi_error.c | 46 ++++ drivers/firmware/powerpc/secvar.c | 326 +++++++++++++++++++++++++++ 7 files changed, 391 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/powerpc/Kconfig create mode 100644 drivers/firmware/powerpc/Makefile create mode 100644 drivers/firmware/powerpc/efi_error.c create mode 100644 drivers/firmware/powerpc/secvar.c