[PATCH v2 1/3] efi_var_file: refactor to move buffer functions
Shantur Rathore
i at shantur.com
Wed Nov 29 19:34:26 CET 2023
Hi Heinrich,
On Wed, Nov 29, 2023 at 5:41 PM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 24.11.23 12:35, Shantur Rathore wrote:
> > Currently efi_var_file.c has functions to store/read
> > EFI variables to/from memory buffer. These functions
> > can be used with other EFI variable stores so move
> > them out to efi_var_common.c
>
> The moved functions relate to filling the memory buffer of variables.
> Wouldn't lib/efi_loader/efi_var_mem.c be more appropriate as target file?
>
As I understand, efi_var_mem.c implements an in-memory store of all
EFI variables.
These functions build a / read from a buffer for writing to an
in-secure storage device ( file / SPI flash ).
The functions are only used by efi_var_sf and efi_var_file hence in
efi_var_common.
Happy to change if you want.
Kind regards,
Shantur
> Best regards
>
> Heinrich
>
> >
> > Signed-off-by: Shantur Rathore <i at shantur.com>
> > ---
> >
> > (no changes since v1)
> >
> > include/efi_variable.h | 5 ++
> > lib/efi_loader/Makefile | 2 +-
> > lib/efi_loader/efi_var_common.c | 109 ++++++++++++++++++++++++++++
> > lib/efi_loader/efi_var_file.c | 121 --------------------------------
> > lib/efi_loader/efi_variable.c | 8 ++-
> > 5 files changed, 122 insertions(+), 123 deletions(-)
> >
> > diff --git a/include/efi_variable.h b/include/efi_variable.h
> > index 805e6c5f1e..bd0a31fc3e 100644
> > --- a/include/efi_variable.h
> > +++ b/include/efi_variable.h
> > @@ -161,6 +161,11 @@ efi_status_t efi_var_to_file(void);
> > efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
> > u32 check_attr_mask);
> >
> > +/* GUID used by Shim to store the MOK database */
> > +#define SHIM_LOCK_GUID \
> > + EFI_GUID(0x605dab50, 0xe046, 0x4300, \
> > + 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
> > +
> > /**
> > * efi_var_restore() - restore EFI variables from buffer
> > *
> > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> > index 8d31fc61c6..33b1910249 100644
> > --- a/lib/efi_loader/Makefile
> > +++ b/lib/efi_loader/Makefile
> > @@ -66,7 +66,7 @@ obj-y += efi_string.o
> > obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o
> > obj-y += efi_var_common.o
> > obj-y += efi_var_mem.o
> > -obj-y += efi_var_file.o
> > +obj-$(CONFIG_EFI_VARIABLE_FILE_STORE) += efi_var_file.o
> > ifeq ($(CONFIG_EFI_MM_COMM_TEE),y)
> > obj-y += efi_variable_tee.o
> > else
> > diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
> > index ad50bffd2b..7509c30b5a 100644
> > --- a/lib/efi_loader/efi_var_common.c
> > +++ b/lib/efi_loader/efi_var_common.c
> > @@ -10,6 +10,7 @@
> > #include <efi_loader.h>
> > #include <efi_variable.h>
> > #include <stdlib.h>
> > +#include <u-boot/crc.h>
> >
> > enum efi_secure_mode {
> > EFI_MODE_SETUP,
> > @@ -40,6 +41,7 @@ static const struct efi_auth_var_name_type name_type[] = {
> >
> > static bool efi_secure_boot;
> > static enum efi_secure_mode efi_secure_mode;
> > +static const efi_guid_t shim_lock_guid = SHIM_LOCK_GUID;
> >
> > /**
> > * efi_efi_get_variable() - retrieve value of a UEFI variable
> > @@ -417,3 +419,110 @@ void *efi_get_var(const u16 *name, const efi_guid_t *vendor, efi_uintn_t *size)
> >
> > return buf;
> > }
> > +
> > +efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
> > + u32 check_attr_mask)
> > +{
> > + size_t len = EFI_VAR_BUF_SIZE;
> > + struct efi_var_file *buf;
> > + struct efi_var_entry *var, *old_var;
> > + size_t old_var_name_length = 2;
> > +
> > + *bufp = NULL; /* Avoid double free() */
> > + buf = calloc(1, len);
> > + if (!buf)
> > + return EFI_OUT_OF_RESOURCES;
> > + var = buf->var;
> > + old_var = var;
> > + for (;;) {
> > + efi_uintn_t data_length, var_name_length;
> > + u8 *data;
> > + efi_status_t ret;
> > +
> > + if ((uintptr_t)buf + len <=
> > + (uintptr_t)var->name + old_var_name_length)
> > + return EFI_BUFFER_TOO_SMALL;
> > +
> > + var_name_length = (uintptr_t)buf + len - (uintptr_t)var->name;
> > + memcpy(var->name, old_var->name, old_var_name_length);
> > + guidcpy(&var->guid, &old_var->guid);
> > + ret = efi_get_next_variable_name_int(
> > + &var_name_length, var->name, &var->guid);
> > + if (ret == EFI_NOT_FOUND)
> > + break;
> > + if (ret != EFI_SUCCESS) {
> > + free(buf);
> > + return ret;
> > + }
> > + old_var_name_length = var_name_length;
> > + old_var = var;
> > +
> > + data = (u8 *)var->name + old_var_name_length;
> > + data_length = (uintptr_t)buf + len - (uintptr_t)data;
> > + ret = efi_get_variable_int(var->name, &var->guid,
> > + &var->attr, &data_length, data,
> > + &var->time);
> > + if (ret != EFI_SUCCESS) {
> > + free(buf);
> > + return ret;
> > + }
> > + if ((var->attr & check_attr_mask) == check_attr_mask) {
> > + var->length = data_length;
> > + var = (struct efi_var_entry *)ALIGN((uintptr_t)data + data_length, 8);
> > + }
> > + }
> > +
> > + buf->reserved = 0;
> > + buf->magic = EFI_VAR_FILE_MAGIC;
> > + len = (uintptr_t)var - (uintptr_t)buf;
> > + buf->crc32 = crc32(0, (u8 *)buf->var,
> > + len - sizeof(struct efi_var_file));
> > + buf->length = len;
> > + *bufp = buf;
> > + *lenp = len;
> > +
> > + return EFI_SUCCESS;
> > +}
> > +
> > +efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
> > +{
> > + struct efi_var_entry *var, *last_var;
> > + u16 *data;
> > + efi_status_t ret;
> > +
> > + if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC ||
> > + buf->crc32 != crc32(0, (u8 *)buf->var,
> > + buf->length - sizeof(struct efi_var_file))) {
> > + log_err("Invalid EFI variables file\n");
> > + return EFI_INVALID_PARAMETER;
> > + }
> > +
> > + last_var = (struct efi_var_entry *)((u8 *)buf + buf->length);
> > + for (var = buf->var; var < last_var;
> > + var = (struct efi_var_entry *)
> > + ALIGN((uintptr_t)data + var->length, 8)) {
> > +
> > + data = var->name + u16_strlen(var->name) + 1;
> > +
> > + /*
> > + * Secure boot related and volatile variables shall only be
> > + * restored from U-Boot's preseed.
> > + */
> > + if (!safe &&
> > + (efi_auth_var_get_type(var->name, &var->guid) !=
> > + EFI_AUTH_VAR_NONE ||
> > + !guidcmp(&var->guid, &shim_lock_guid) ||
> > + !(var->attr & EFI_VARIABLE_NON_VOLATILE)))
> > + continue;
> > + if (!var->length)
> > + continue;
> > + if (efi_var_mem_find(&var->guid, var->name, NULL))
> > + continue;
> > + ret = efi_var_mem_ins(var->name, &var->guid, var->attr,
> > + var->length, data, 0, NULL,
> > + var->time);
> > + if (ret != EFI_SUCCESS)
> > + log_err("Failed to set EFI variable %ls\n", var->name);
> > + }
> > + return EFI_SUCCESS;
> > +}
> > diff --git a/lib/efi_loader/efi_var_file.c b/lib/efi_loader/efi_var_file.c
> > index d7dba05071..166501a355 100644
> > --- a/lib/efi_loader/efi_var_file.c
> > +++ b/lib/efi_loader/efi_var_file.c
> > @@ -15,17 +15,9 @@
> > #include <mapmem.h>
> > #include <efi_loader.h>
> > #include <efi_variable.h>
> > -#include <u-boot/crc.h>
> >
> > #define PART_STR_LEN 10
> >
> > -/* GUID used by Shim to store the MOK database */
> > -#define SHIM_LOCK_GUID \
> > - EFI_GUID(0x605dab50, 0xe046, 0x4300, \
> > - 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
> > -
> > -static const efi_guid_t shim_lock_guid = SHIM_LOCK_GUID;
> > -
> > /**
> > * efi_set_blk_dev_to_system_partition() - select EFI system partition
> > *
> > @@ -53,70 +45,6 @@ static efi_status_t __maybe_unused efi_set_blk_dev_to_system_partition(void)
> > return EFI_SUCCESS;
> > }
> >
> > -efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
> > - u32 check_attr_mask)
> > -{
> > - size_t len = EFI_VAR_BUF_SIZE;
> > - struct efi_var_file *buf;
> > - struct efi_var_entry *var, *old_var;
> > - size_t old_var_name_length = 2;
> > -
> > - *bufp = NULL; /* Avoid double free() */
> > - buf = calloc(1, len);
> > - if (!buf)
> > - return EFI_OUT_OF_RESOURCES;
> > - var = buf->var;
> > - old_var = var;
> > - for (;;) {
> > - efi_uintn_t data_length, var_name_length;
> > - u8 *data;
> > - efi_status_t ret;
> > -
> > - if ((uintptr_t)buf + len <=
> > - (uintptr_t)var->name + old_var_name_length)
> > - return EFI_BUFFER_TOO_SMALL;
> > -
> > - var_name_length = (uintptr_t)buf + len - (uintptr_t)var->name;
> > - memcpy(var->name, old_var->name, old_var_name_length);
> > - guidcpy(&var->guid, &old_var->guid);
> > - ret = efi_get_next_variable_name_int(
> > - &var_name_length, var->name, &var->guid);
> > - if (ret == EFI_NOT_FOUND)
> > - break;
> > - if (ret != EFI_SUCCESS) {
> > - free(buf);
> > - return ret;
> > - }
> > - old_var_name_length = var_name_length;
> > - old_var = var;
> > -
> > - data = (u8 *)var->name + old_var_name_length;
> > - data_length = (uintptr_t)buf + len - (uintptr_t)data;
> > - ret = efi_get_variable_int(var->name, &var->guid,
> > - &var->attr, &data_length, data,
> > - &var->time);
> > - if (ret != EFI_SUCCESS) {
> > - free(buf);
> > - return ret;
> > - }
> > - if ((var->attr & check_attr_mask) == check_attr_mask) {
> > - var->length = data_length;
> > - var = (struct efi_var_entry *)ALIGN((uintptr_t)data + data_length, 8);
> > - }
> > - }
> > -
> > - buf->reserved = 0;
> > - buf->magic = EFI_VAR_FILE_MAGIC;
> > - len = (uintptr_t)var - (uintptr_t)buf;
> > - buf->crc32 = crc32(0, (u8 *)buf->var,
> > - len - sizeof(struct efi_var_file));
> > - buf->length = len;
> > - *bufp = buf;
> > - *lenp = len;
> > -
> > - return EFI_SUCCESS;
> > -}
> > -
> > /**
> > * efi_var_to_file() - save non-volatile variables as file
> > *
> > @@ -126,7 +54,6 @@ efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *
> > */
> > efi_status_t efi_var_to_file(void)
> > {
> > -#ifdef CONFIG_EFI_VARIABLE_FILE_STORE
> > efi_status_t ret;
> > struct efi_var_file *buf;
> > loff_t len;
> > @@ -150,52 +77,6 @@ error:
> > log_err("Failed to persist EFI variables\n");
> > free(buf);
> > return ret;
> > -#else
> > - return EFI_SUCCESS;
> > -#endif
> > -}
> > -
> > -efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
> > -{
> > - struct efi_var_entry *var, *last_var;
> > - u16 *data;
> > - efi_status_t ret;
> > -
> > - if (buf->reserved || buf->magic != EFI_VAR_FILE_MAGIC ||
> > - buf->crc32 != crc32(0, (u8 *)buf->var,
> > - buf->length - sizeof(struct efi_var_file))) {
> > - log_err("Invalid EFI variables file\n");
> > - return EFI_INVALID_PARAMETER;
> > - }
> > -
> > - last_var = (struct efi_var_entry *)((u8 *)buf + buf->length);
> > - for (var = buf->var; var < last_var;
> > - var = (struct efi_var_entry *)
> > - ALIGN((uintptr_t)data + var->length, 8)) {
> > -
> > - data = var->name + u16_strlen(var->name) + 1;
> > -
> > - /*
> > - * Secure boot related and volatile variables shall only be
> > - * restored from U-Boot's preseed.
> > - */
> > - if (!safe &&
> > - (efi_auth_var_get_type(var->name, &var->guid) !=
> > - EFI_AUTH_VAR_NONE ||
> > - !guidcmp(&var->guid, &shim_lock_guid) ||
> > - !(var->attr & EFI_VARIABLE_NON_VOLATILE)))
> > - continue;
> > - if (!var->length)
> > - continue;
> > - if (efi_var_mem_find(&var->guid, var->name, NULL))
> > - continue;
> > - ret = efi_var_mem_ins(var->name, &var->guid, var->attr,
> > - var->length, data, 0, NULL,
> > - var->time);
> > - if (ret != EFI_SUCCESS)
> > - log_err("Failed to set EFI variable %ls\n", var->name);
> > - }
> > - return EFI_SUCCESS;
> > }
> >
> > /**
> > @@ -214,7 +95,6 @@ efi_status_t efi_var_restore(struct efi_var_file *buf, bool safe)
> > */
> > efi_status_t efi_var_from_file(void)
> > {
> > -#ifdef CONFIG_EFI_VARIABLE_FILE_STORE
> > struct efi_var_file *buf;
> > loff_t len;
> > efi_status_t ret;
> > @@ -239,6 +119,5 @@ efi_status_t efi_var_from_file(void)
> > log_err("Invalid EFI variables file\n");
> > error:
> > free(buf);
> > -#endif
> > return EFI_SUCCESS;
> > }
> > diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
> > index be95ed44e6..adc5ac6a80 100644
> > --- a/lib/efi_loader/efi_variable.c
> > +++ b/lib/efi_loader/efi_variable.c
> > @@ -357,8 +357,11 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
> > * Write non-volatile EFI variables to file
> > * TODO: check if a value change has occured to avoid superfluous writes
> > */
> > - if (attributes & EFI_VARIABLE_NON_VOLATILE)
> > +#if CONFIG_IS_ENABLED(EFI_VARIABLE_FILE_STORE)
> > + if (attributes & EFI_VARIABLE_NON_VOLATILE) {
> > efi_var_to_file();
> > + }
> > +#endif
> >
> > return EFI_SUCCESS;
> > }
> > @@ -466,9 +469,12 @@ efi_status_t efi_init_variables(void)
> > if (ret != EFI_SUCCESS)
> > return ret;
> >
> > +#if CONFIG_IS_ENABLED(EFI_VARIABLE_FILE_STORE)
> > ret = efi_var_from_file();
> > if (ret != EFI_SUCCESS)
> > return ret;
> > +#endif
> > +
> > if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
> > ret = efi_var_restore((struct efi_var_file *)
> > __efi_var_file_begin, true);
>
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