freebsd-skq/lib/libefivar/efivar.c
imp fe47a5f058 Minor fixes to edge cases in efi_get_next_variable_name
Fix allocating more memory for the names (unlikely to be needed, but
still best to get right) to ask for the length the kernel told use we
needed, not the old length of the variable. Mind the proper NUL that
we add in the space we allocate. Free the old name string before we
allcoate a new one to limit what we leak to the last one (free passed
in name for the last one in the list), and detect the last one by rv
!= 0 and errno == ENOENT, rather then just the former to avoid false
positives if errno happens to be ENOENT on entry.

Sponsored by: Netflix
2017-09-13 04:32:23 +00:00

401 lines
9.9 KiB
C

/*-
* Copyright (c) 2016 Netflix, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <efivar.h>
#include <sys/efiio.h>
#include <sys/param.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "efichar.h"
static int efi_fd = -2;
#define Z { 0, 0, 0, 0, 0, { 0 } }
const efi_guid_t efi_guid_empty = Z;
static struct uuid_table guid_tbl [] =
{
{ "00000000-0000-0000-0000-000000000000", "zero", Z },
{ "093e0fae-a6c4-4f50-9f1b-d41e2b89c19a", "sha512", Z },
{ "0abba7dc-e516-4167-bbf5-4d9d1c739416", "redhat", Z },
{ "0b6e5233-a65c-44c9-9407-d9ab83bfc8bd", "sha224", Z },
{ "126a762d-5758-4fca-8531-201a7f57f850", "lenovo_boot_menu", Z },
{ "3bd2a492-96c0-4079-b420-fcf98ef103ed", "x509_sha256", Z },
{ "3c5766e8-269c-4e34-aa14-ed776e85b3b6", "rsa2048", Z },
{ "3CC24E96-22C7-41D8-8863-8E39DCDCC2CF", "lenovo", Z },
{ "3f7e615b-0d45-4f80-88dc-26b234958560", "lenovo_diag", Z },
{ "446dbf63-2502-4cda-bcfa-2465d2b0fe9d", "x509_sha512", Z },
{ "4aafd29d-68df-49ee-8aa9-347d375665a7", "pkcs7_cert", Z },
{ "605dab50-e046-4300-abb6-3dd810dd8b23", "shim", Z },
{ "665d3f60-ad3e-4cad-8e26-db46eee9f1b5", "lenovo_rescue", Z },
{ "67f8444f-8743-48f1-a328-1eaab8736080", "rsa2048_sha1", Z },
{ "7076876e-80c2-4ee6-aad2-28b349a6865b", "x509_sha384", Z },
{ "721c8b66-426c-4e86-8e99-3457c46ab0b9", "lenovo_setup", Z },
{ "77fa9abd-0359-4d32-bd60-28f4e78f784b", "microsoft", Z },
{ "7FACC7B6-127F-4E9C-9C5D-080F98994345", "lenovo_2", Z },
{ "826ca512-cf10-4ac9-b187-be01496631bd", "sha1", Z },
{ "82988420-7467-4490-9059-feb448dd1963", "lenovo_me_config", Z },
{ "8be4df61-93ca-11d2-aa0d-00e098032b8c", "global", Z },
{ "a5c059a1-94e4-4aa7-87b5-ab155c2bf072", "x509_cert", Z },
{ "a7717414-c616-4977-9420-844712a735bf", "rsa2048_sha256_cert", Z },
{ "a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380", "lenovo_diag_splash", Z },
{ "ade9e48f-9cb8-98e6-31af-b4e6009e2fe3", "redhat_2", Z },
{ "bc7838d2-0f82-4d60-8316-c068ee79d25b", "lenovo_msg", Z },
{ "c1c41626-504c-4092-aca9-41f936934328", "sha256", Z },
{ "c57ad6b7-0515-40a8-9d21-551652854e37", "shell", Z },
{ "d719b2cb-3d3a-4596-a3bc-dad00e67656f", "security", Z },
{ "e2b36190-879b-4a3d-ad8d-f2e7bba32784", "rsa2048_sha256", Z },
{ "ff3e5307-9fd0-48c9-85f1-8ad56c701e01", "sha384", Z },
{ "f46ee6f4-4785-43a3-923d-7f786c3c8479", "lenovo_startup_interrupt", Z },
{ "ffffffff-ffff-ffff-ffff-ffffffffffff", "zzignore-this-guid", Z },
};
#undef Z
static void
efi_guid_tbl_compile(void)
{
size_t i;
uint32_t status;
static int done = 0;
if (done)
return;
for (i = 0; i < nitems(guid_tbl); i++) {
uuid_from_string(guid_tbl[i].uuid_str, &guid_tbl[i].guid,
&status);
/* all f's is a bad version, so ignore that error */
if (status != uuid_s_ok && status != uuid_s_bad_version)
fprintf(stderr, "Can't convert %s to a uuid for %s: %d\n",
guid_tbl[i].uuid_str, guid_tbl[i].name, (int)status);
}
done = 1;
}
int
efi_known_guid(struct uuid_table **tbl)
{
*tbl = guid_tbl;
return (nitems(guid_tbl));
}
static int
efi_open_dev(void)
{
if (efi_fd == -2)
efi_fd = open("/dev/efi", O_RDWR);
if (efi_fd < 0)
efi_fd = -1;
else
efi_guid_tbl_compile();
return (efi_fd);
}
static void
efi_var_reset(struct efi_var_ioc *var)
{
var->name = NULL;
var->namesize = 0;
memset(&var->vendor, 0, sizeof(var->vendor));
var->attrib = 0;
var->data = NULL;
var->datasize = 0;
}
static int
rv_to_linux_rv(int rv)
{
if (rv == 0)
rv = 1;
else
rv = -errno;
return (rv);
}
int
efi_append_variable(efi_guid_t guid, const char *name,
uint8_t *data, size_t data_size, uint32_t attributes)
{
return efi_set_variable(guid, name, data, data_size,
attributes | EFI_VARIABLE_APPEND_WRITE, 0);
}
int
efi_del_variable(efi_guid_t guid, const char *name)
{
/* data_size of 0 deletes the variable */
return efi_set_variable(guid, name, NULL, 0, 0, 0);
}
int
efi_get_variable(efi_guid_t guid, const char *name,
uint8_t **data, size_t *data_size, uint32_t *attributes)
{
struct efi_var_ioc var;
int rv;
static uint8_t buf[1024*32];
if (efi_open_dev() == -1)
return -1;
efi_var_reset(&var);
rv = utf8_to_ucs2(name, &var.name, &var.namesize);
if (rv != 0)
goto errout;
var.vendor = guid;
var.data = buf;
var.datasize = sizeof(buf);
rv = ioctl(efi_fd, EFIIOC_VAR_GET, &var);
if (data_size != NULL)
*data_size = var.datasize;
if (data != NULL)
*data = buf;
if (attributes != NULL)
*attributes = var.attrib;
errout:
free(var.name);
return rv_to_linux_rv(rv);
}
int
efi_get_variable_attributes(efi_guid_t guid, const char *name,
uint32_t *attributes)
{
/* Make sure this construct works -- I think it will fail */
return efi_get_variable(guid, name, NULL, NULL, attributes);
}
int
efi_get_variable_size(efi_guid_t guid, const char *name,
size_t *size)
{
/* XXX check to make sure this matches the linux value */
*size = 0;
return efi_get_variable(guid, name, NULL, size, NULL);
}
int
efi_get_next_variable_name(efi_guid_t **guid, char **name)
{
struct efi_var_ioc var;
int rv;
static efi_char *buf;
static size_t buflen = 256 * sizeof(efi_char);
static efi_guid_t retguid;
size_t size;
if (efi_open_dev() == -1)
return -1;
/*
* Always allocate enough for an extra NUL on the end, but don't tell
* the IOCTL about it so we can NUL terminate the name before converting
* it to UTF8.
*/
if (buf == NULL)
buf = malloc(buflen + sizeof(efi_char));
again:
efi_var_reset(&var);
var.name = buf;
var.namesize = buflen;
if (*name == NULL) {
*buf = 0;
/* GUID zeroed in var_reset */
} else {
rv = utf8_to_ucs2(*name, &var.name, &size);
if (rv != 0)
goto errout;
var.vendor = **guid;
}
rv = ioctl(efi_fd, EFIIOC_VAR_NEXT, &var);
if (rv == 0 && var.name == NULL) {
/*
* Variable name not long enough, so allocate more space for the
* name and try again. As above, mind the NUL we add.
*/
void *new = realloc(buf, var.namesize + sizeof(efi_char));
if (new == NULL) {
rv = -1;
errno = ENOMEM;
goto done;
}
buflen = var.namesize;
buf = new;
goto again;
}
if (rv == 0) {
free(*name); /* Free last name, to avoid leaking */
*name = NULL; /* Force ucs2_to_utf8 to malloc new space */
var.name[var.namesize / sizeof(efi_char)] = 0; /* EFI doesn't NUL terminate */
rv = ucs2_to_utf8(var.name, name);
if (rv != 0)
goto errout;
retguid = var.vendor;
*guid = &retguid;
}
errout:
/* XXX The linux interface expects name to be a static buffer -- fix or leak memory? */
/* XXX for the moment, we free just before we'd leak, but still leak last one */
done:
if (rv != 0 && errno == ENOENT) {
errno = 0;
free(*name); /* Free last name, to avoid leaking */
return 0;
}
return (rv_to_linux_rv(rv));
}
int
efi_guid_cmp(const efi_guid_t *guid1, const efi_guid_t *guid2)
{
uint32_t status;
return uuid_compare(guid1, guid2, &status);
}
int
efi_guid_is_zero(const efi_guid_t *guid)
{
uint32_t status;
return uuid_is_nil(guid, &status);
}
int
efi_guid_to_name(efi_guid_t *guid, char **name)
{
size_t i;
uint32_t status;
efi_guid_tbl_compile();
for (i = 0; i < nitems(guid_tbl); i++) {
if (uuid_equal(guid, &guid_tbl[i].guid, &status)) {
*name = strdup(guid_tbl[i].name);
return (0);
}
}
return (efi_guid_to_str(guid, name));
}
int
efi_guid_to_symbol(efi_guid_t *guid __unused, char **symbol __unused)
{
/*
* Unsure what this is used for, efibootmgr doesn't use it.
* Leave unimplemented for now.
*/
return -1;
}
int
efi_guid_to_str(const efi_guid_t *guid, char **sp)
{
uint32_t status;
/* knows efi_guid_t is a typedef of uuid_t */
uuid_to_string(guid, sp, &status);
return (status == uuid_s_ok ? 0 : -1);
}
int
efi_name_to_guid(const char *name, efi_guid_t *guid)
{
size_t i;
efi_guid_tbl_compile();
for (i = 0; i < nitems(guid_tbl); i++) {
if (strcmp(name, guid_tbl[i].name) == 0) {
*guid = guid_tbl[i].guid;
return (0);
}
}
return (efi_str_to_guid(name, guid));
}
int
efi_set_variable(efi_guid_t guid, const char *name,
uint8_t *data, size_t data_size, uint32_t attributes, mode_t mode __unused)
{
struct efi_var_ioc var;
int rv;
if (efi_open_dev() == -1)
return -1;
efi_var_reset(&var);
rv = utf8_to_ucs2(name, &var.name, &var.namesize);
if (rv != 0)
goto errout;
var.vendor = guid;
var.data = data;
var.datasize = data_size;
var.attrib = attributes;
rv = ioctl(efi_fd, EFIIOC_VAR_SET, &var);
errout:
free(var.name);
return rv;
}
int
efi_str_to_guid(const char *s, efi_guid_t *guid)
{
uint32_t status;
/* knows efi_guid_t is a typedef of uuid_t */
uuid_from_string(s, guid, &status);
return (status == uuid_s_ok ? 0 : -1);
}
int
efi_variables_supported(void)
{
return efi_open_dev() != -1;
}