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Move signature verification implementation to the library

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Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
This commit is contained in:
Dmitry Kasatkin 2014-01-23 16:35:30 +02:00
parent 018495c87f
commit 6aabda5b65
3 changed files with 677 additions and 626 deletions
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651
src/evmctl.c
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@ -41,195 +41,11 @@
#include <signal.h>
#include <keyutils.h>
#include <asm/byteorder.h>
#include <syslog.h>
#include <attr/xattr.h>
#include <dirent.h>
#include <ctype.h>
#include <stdbool.h>
#include <openssl/sha.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/hmac.h>
#include <openssl/engine.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/x509.h>
#define USE_FPRINTF
#ifdef USE_FPRINTF
#define do_log(level, fmt, args...) ({ if (level <= verbose) fprintf(stderr, fmt, ##args); })
#define do_log_dump(level, p, len, cr) ({ if (level <= verbose) do_dump(stderr, p, len, cr); })
#else
#define do_log(level, fmt, args...) syslog(level, fmt, ##args)
#define do_log_dump(p, len)
#endif
#ifdef DEBUG
#define log_debug(fmt, args...) do_log(LOG_DEBUG, "%s:%d " fmt, __func__ , __LINE__ , ##args)
#define log_debug_dump(p, len) do_log_dump(LOG_DEBUG, p, len, true)
#define log_debug_dump_n(p, len) do_log_dump(LOG_DEBUG, p, len, false)
#else
#define log_debug(fmt, args...)
#define log_debug_dump(p, len)
#endif
#define log_dump(p, len) do_log_dump(LOG_INFO, p, len, true)
#define log_dump_n(p, len) do_log_dump(LOG_INFO, p, len, false)
#define log_info(fmt, args...) do_log(LOG_INFO, fmt, ##args)
#define log_err(fmt, args...) do_log(LOG_ERR, fmt, ##args)
#define log_errno(fmt, args...) do_log(LOG_ERR, fmt ": errno: %s (%d)\n", ##args, strerror(errno), errno)
#define DATA_SIZE 4096
#define SHA1_HASH_LEN 20
#define EXT2_IOC_GETVERSION _IOR('v', 1, long)
#define EXT34_IOC_GETVERSION _IOR('f', 3, long)
#define FS_IOC_GETFLAGS _IOR('f', 1, long)
#define FS_IOC_SETFLAGS _IOW('f', 2, long)
#define FS_IOC32_GETFLAGS _IOR('f', 1, int)
#define FS_IOC32_SETFLAGS _IOW('f', 2, int)
#define __packed __attribute__((packed))
struct h_misc {
unsigned long ino;
uint32_t generation;
uid_t uid;
gid_t gid;
unsigned short mode;
} hmac_misc;
enum pubkey_algo {
PUBKEY_ALGO_RSA,
PUBKEY_ALGO_MAX,
};
enum digest_algo {
DIGEST_ALGO_SHA1,
DIGEST_ALGO_SHA256,
DIGEST_ALGO_MAX
};
enum digsig_version {
DIGSIG_VERSION_1 = 1,
DIGSIG_VERSION_2
};
struct pubkey_hdr {
uint8_t version; /* key format version */
uint32_t timestamp; /* key made, always 0 for now */
uint8_t algo;
uint8_t nmpi;
char mpi[0];
} __packed;
struct signature_hdr {
uint8_t version; /* signature format version */
uint32_t timestamp; /* signature made */
uint8_t algo;
uint8_t hash;
uint8_t keyid[8];
uint8_t nmpi;
char mpi[0];
} __packed;
enum pkey_hash_algo {
PKEY_HASH_MD4,
PKEY_HASH_MD5,
PKEY_HASH_SHA1,
PKEY_HASH_RIPE_MD_160,
PKEY_HASH_SHA256,
PKEY_HASH_SHA384,
PKEY_HASH_SHA512,
PKEY_HASH_SHA224,
PKEY_HASH__LAST
};
const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
[PKEY_HASH_MD4] = "md4",
[PKEY_HASH_MD5] = "md5",
[PKEY_HASH_SHA1] = "sha1",
[PKEY_HASH_RIPE_MD_160] = "rmd160",
[PKEY_HASH_SHA256] = "sha256",
[PKEY_HASH_SHA384] = "sha384",
[PKEY_HASH_SHA512] = "sha512",
[PKEY_HASH_SHA224] = "sha224",
};
/*
* signature format v2 - for using with asymmetric keys
*/
struct signature_v2_hdr {
uint8_t version; /* signature format version */
uint8_t hash_algo; /* Digest algorithm [enum pkey_hash_algo] */
uint32_t keyid; /* IMA key identifier - not X509/PGP specific*/
uint16_t sig_size; /* signature size */
uint8_t sig[0]; /* signature payload */
} __packed;
/*
* Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
*/
static const uint8_t RSA_digest_info_MD5[] = {
0x30, 0x20, 0x30, 0x0C, 0x06, 0x08,
0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */
0x05, 0x00, 0x04, 0x10
};
static const uint8_t RSA_digest_info_SHA1[] = {
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x0E, 0x03, 0x02, 0x1A,
0x05, 0x00, 0x04, 0x14
};
static const uint8_t RSA_digest_info_RIPE_MD_160[] = {
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x24, 0x03, 0x02, 0x01,
0x05, 0x00, 0x04, 0x14
};
static const uint8_t RSA_digest_info_SHA224[] = {
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
0x05, 0x00, 0x04, 0x1C
};
static const uint8_t RSA_digest_info_SHA256[] = {
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
0x05, 0x00, 0x04, 0x20
};
static const uint8_t RSA_digest_info_SHA384[] = {
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
0x05, 0x00, 0x04, 0x30
};
static const uint8_t RSA_digest_info_SHA512[] = {
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
0x05, 0x00, 0x04, 0x40
};
static const struct RSA_ASN1_template {
const uint8_t *data;
size_t size;
} RSA_ASN1_templates[PKEY_HASH__LAST] = {
#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) }
[PKEY_HASH_MD5] = _(MD5),
[PKEY_HASH_SHA1] = _(SHA1),
[PKEY_HASH_RIPE_MD_160] = _(RIPE_MD_160),
[PKEY_HASH_SHA256] = _(SHA256),
[PKEY_HASH_SHA384] = _(SHA384),
[PKEY_HASH_SHA512] = _(SHA512),
[PKEY_HASH_SHA224] = _(SHA224),
#undef _
};
#include <libevm.h>
static char *evm_config_xattrnames[] = {
"security.selinux",
@ -247,22 +63,16 @@ struct command {
char *msg; /* extra info message */
};
static int verbose = LOG_INFO - 1;
static int g_argc;
static char **g_argv;
static int xattr = 1;
static int sigdump;
static int digest;
static int digsig;
static const char *hash_algo = "sha1";
static int user_hash_algo;
static char *keypass;
static int sigfile;
static int modsig;
static char *uuid_str;
static int x509;
static int user_sig_type;
static char *keyfile;
static char *search_type;
static int recursive;
static dev_t fs_dev;
@ -280,45 +90,9 @@ typedef int (*sign_hash_fn_t)(const char *algo, const unsigned char *hash, int s
static sign_hash_fn_t sign_hash;
typedef int (*verify_hash_fn_t)(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile);
static verify_hash_fn_t verify_hash;
struct command cmds[];
static void print_usage(struct command *cmd);
static void do_dump(FILE *fp, const void *ptr, int len, bool cr)
{
int i;
uint8_t *data = (uint8_t *) ptr;
for (i = 0; i < len; i++)
fprintf(fp, "%02x", data[i]);
if (cr)
fprintf(fp, "\n");
}
static void dump(const void *ptr, int len)
{
do_dump(stdout, ptr, len, true);
}
static inline int get_filesize(const char *filename)
{
struct stat stats;
/* Need to know the file length */
stat(filename, &stats);
return (int)stats.st_size;
}
static inline int get_fdsize(int fd)
{
struct stat stats;
/* Need to know the file length */
fstat(fd, &stats);
return (int)stats.st_size;
}
static int bin2file(const char *file, const char *ext, const unsigned char *data, int len)
{
FILE *fp;
@ -404,47 +178,6 @@ static int key2bin(RSA *key, unsigned char *pub)
return offset;
}
static RSA *read_pub_key(const char *keyfile)
{
FILE *fp;
RSA *key = NULL;
X509 *crt = NULL;
EVP_PKEY *pkey = NULL;
fp = fopen(keyfile, "r");
if (!fp) {
log_err("Unable to open keyfile %s\n", keyfile);
return NULL;
}
if (x509) {
crt = d2i_X509_fp(fp, NULL);
if (!crt) {
log_err("d2i_X509_fp() failed\n");
goto out;
}
pkey = X509_extract_key(crt);
if (!pkey) {
log_err("X509_extract_key() failed\n");
goto out;
}
key = EVP_PKEY_get1_RSA(pkey);
} else {
key = PEM_read_RSA_PUBKEY(fp, NULL, NULL, NULL);
}
if (!key)
log_err("PEM_read_RSA_PUBKEY() failed\n");
out:
if (pkey)
EVP_PKEY_free(pkey);
if (crt)
X509_free(crt);
fclose(fp);
return key;
}
static void calc_keyid_v1(uint8_t *keyid, char *str, const unsigned char *pkey, int len)
{
uint8_t sha1[SHA_DIGEST_LENGTH];
@ -501,7 +234,7 @@ static RSA *read_priv_key(const char *keyfile)
return key;
}
int get_hash_algo_v1(const char *algo)
static int get_hash_algo_v1(const char *algo)
{
if (!strcmp(algo, "sha1"))
@ -565,24 +298,13 @@ static int sign_hash_v1(const char *hashalgo, const unsigned char *hash, int siz
*blen = __cpu_to_be16(len << 3);
len += sizeof(*hdr) + 2;
log_info("evm/ima signature: %d bytes\n", len);
if (sigdump || verbose >= LOG_INFO)
if (sigdump || params.verbose >= LOG_INFO)
dump(sig, len);
out:
RSA_free(key);
return len;
}
uint8_t get_hash_algo(const char *algo)
{
int i;
for (i = 0; i < PKEY_HASH__LAST; i++)
if (!strcmp(algo, pkey_hash_algo[i]))
return i;
return PKEY_HASH_SHA1;
}
static int sign_hash_v2(const char *algo, const unsigned char *hash, int size, const char *keyfile, unsigned char *sig)
{
struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
@ -623,7 +345,7 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, int size, c
hdr->sig_size = __cpu_to_be16(len);
len += sizeof(*hdr);
log_info("evm/ima signature: %d bytes\n", len);
if (sigdump || verbose >= LOG_INFO)
if (sigdump || params.verbose >= LOG_INFO)
dump(sig, len);
out:
if (buf)
@ -864,176 +586,19 @@ static int sign_evm(const char *file, const char *key)
return 0;
}
static int add_file_hash(const char *file, EVP_MD_CTX *ctx)
{
uint8_t *data;
int err, size, bs = DATA_SIZE;
size_t len;
FILE *fp;
data = malloc(bs);
if (!data) {
log_err("malloc failed\n");
return -1;
}
fp = fopen(file, "r");
if (!fp) {
log_err("Unable to open %s\n", file);
return -1;
}
for (size = get_fdsize(fileno(fp)); size; size -= len) {
len = MIN(size, bs);
err = fread(data, len, 1, fp);
if (!err) {
if (ferror(fp)) {
log_err("fread() error\n\n");
return -1;
}
break;
}
err = EVP_DigestUpdate(ctx, data, len);
if (!err) {
log_err("EVP_DigestUpdate() failed\n");
return 1;
}
}
fclose(fp);
free(data);
return 0;
}
static int add_dir_hash(const char *file, EVP_MD_CTX *ctx)
{
int err;
struct dirent *de;
DIR *dir;
unsigned long long ino, off;
unsigned int type;
dir = opendir(file);
if (!dir) {
log_err("Unable to open %s\n", file);
return -1;
}
while ((de = readdir(dir))) {
ino = de->d_ino;
off = de->d_off;
type = de->d_type;
log_debug("entry: %s, ino: %llu, type: %u, off: %llu, reclen: %hu\n",
de->d_name, ino, type, off, de->d_reclen);
err = EVP_DigestUpdate(ctx, de->d_name, strlen(de->d_name));
/*err |= EVP_DigestUpdate(ctx, &off, sizeof(off));*/
err |= EVP_DigestUpdate(ctx, &ino, sizeof(ino));
err |= EVP_DigestUpdate(ctx, &type, sizeof(type));
if (!err) {
log_err("EVP_DigestUpdate() failed\n");
return 1;
}
}
closedir(dir);
return 0;
}
static int add_link_hash(const char *path, EVP_MD_CTX *ctx)
{
int err;
char buf[1024];
err = readlink(path, buf, sizeof(buf));
if (err <= 0)
return -1;
log_info("link: %s -> %.*s\n", path, err, buf);
return !EVP_DigestUpdate(ctx, buf, err);
}
static int add_dev_hash(struct stat *st, EVP_MD_CTX *ctx)
{
uint32_t dev = st->st_rdev;
unsigned major = (dev & 0xfff00) >> 8;
unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
log_info("device: %u:%u\n", major, minor);
return !EVP_DigestUpdate(ctx, &dev, sizeof(dev));
}
static int calc_hash(const char *file, uint8_t *hash)
{
struct stat st;
EVP_MD_CTX ctx;
const EVP_MD *md;
unsigned int mdlen;
int err;
/* Need to know the file length */
err = lstat(file, &st);
if (err < 0) {
log_err("stat() failed\n");
return err;
}
md = EVP_get_digestbyname(hash_algo);
if (!md) {
log_err("EVP_get_digestbyname() failed\n");
return 1;
}
err = EVP_DigestInit(&ctx, md);
if (!err) {
log_err("EVP_DigestInit() failed\n");
return 1;
}
switch (st.st_mode & S_IFMT) {
case S_IFREG:
err = add_file_hash(file, &ctx);
break;
case S_IFDIR:
err = add_dir_hash(file, &ctx);
break;
case S_IFLNK:
err = add_link_hash(file, &ctx);
break;
case S_IFIFO: case S_IFSOCK:
case S_IFCHR: case S_IFBLK:
err = add_dev_hash(&st, &ctx);
break;
default:
log_errno("Unsupported file type");
return -1;
}
if (err)
return err;
err = EVP_DigestFinal(&ctx, hash, &mdlen);
if (!err) {
log_err("EVP_DigestFinal() failed\n");
return 1;
}
return mdlen;
}
static int hash_ima(const char *file)
{
unsigned char hash[65] = "\x01"; /* MAX hash size + 1 */
int len, err;
len = calc_hash(file, hash + 1);
len = ima_calc_hash(file, hash + 1);
if (len <= 1)
return len;
if (verbose >= LOG_INFO)
if (params.verbose >= LOG_INFO)
log_info("hash: ");
if (sigdump || verbose >= LOG_INFO)
if (sigdump || params.verbose >= LOG_INFO)
dump(hash, len + 1);
if (xattr) {
@ -1067,11 +632,11 @@ static int sign_ima(const char *file, const char *key)
char magic[] = "This Is A Crypto Signed Module";
int len, err;
len = calc_hash(file, hash);
len = ima_calc_hash(file, hash);
if (len <= 1)
return len;
len = sign_hash(hash_algo, hash, len, key, sig + 1);
len = sign_hash(params.hash_algo, hash, len, key, sig + 1);
if (len <= 1)
return len;
@ -1134,7 +699,7 @@ static int sign_ima_file(const char *file)
{
char *key;
key = keyfile ? : "/etc/keys/privkey_evm.pem";
key = params.keyfile ? : "/etc/keys/privkey_evm.pem";
return sign_ima(file, key);
}
@ -1169,7 +734,7 @@ static int sign_evm_path(const char *file)
char *key;
int err;
key = keyfile ? : "/etc/keys/privkey_evm.pem";
key = params.keyfile ? : "/etc/keys/privkey_evm.pem";
if (digsig) {
err = sign_ima(file, key);
@ -1211,93 +776,6 @@ static int cmd_sign_evm(struct command *cmd)
return err;
}
static int verify_hash_v1(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile)
{
int err, len;
SHA_CTX ctx;
unsigned char out[1024];
RSA *key;
unsigned char sighash[20];
struct signature_hdr *hdr = (struct signature_hdr *)sig;
log_info("hash: ");
log_dump(hash, size);
key = read_pub_key(keyfile);
if (!key)
return 1;
SHA1_Init(&ctx);
SHA1_Update(&ctx, hash, size);
SHA1_Update(&ctx, hdr, sizeof(*hdr));
SHA1_Final(sighash, &ctx);
log_info("sighash: ");
log_dump(sighash, sizeof(sighash));
err = RSA_public_decrypt(siglen - sizeof(*hdr) - 2, sig + sizeof(*hdr) + 2, out, key, RSA_PKCS1_PADDING);
RSA_free(key);
if (err < 0) {
log_err("RSA_public_decrypt() failed: %d\n", err);
return 1;
}
len = err;
if (len != sizeof(sighash) || memcmp(out, sighash, len) != 0) {
log_err("Verification failed: %d\n", err);
return -1;
} else {
/*log_info("Verification is OK\n");*/
printf("Verification is OK\n");
}
return 0;
}
static int verify_hash_v2(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile)
{
int err, len;
unsigned char out[1024];
RSA *key;
struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
const struct RSA_ASN1_template *asn1;
log_info("hash: ");
log_dump(hash, size);
key = read_pub_key(keyfile);
if (!key)
return 1;
err = RSA_public_decrypt(siglen - sizeof(*hdr), sig + sizeof(*hdr), out, key, RSA_PKCS1_PADDING);
RSA_free(key);
if (err < 0) {
log_err("RSA_public_decrypt() failed: %d\n", err);
return 1;
}
len = err;
asn1 = &RSA_ASN1_templates[hdr->hash_algo];
if (len < asn1->size || memcmp(out, asn1->data, asn1->size)) {
log_err("Verification failed: %d\n", err);
return -1;
}
len -= asn1->size;
if (len != size || memcmp(out + asn1->size, hash, len)) {
log_err("Verification failed: %d\n", err);
return -1;
}
/*log_info("Verification is OK\n");*/
printf("Verification is OK\n");
return 0;
}
static int verify_evm(const char *file, const char *key)
{
unsigned char hash[20];
@ -1319,7 +797,7 @@ static int verify_evm(const char *file, const char *key)
return -1;
}
return verify_hash(hash, sizeof(hash), sig + 1, len - 1, key);
return params.verify_hash(hash, sizeof(hash), sig + 1, len - 1, key);
}
static int cmd_verify_evm(struct command *cmd)
@ -1332,86 +810,13 @@ static int cmd_verify_evm(struct command *cmd)
return -1;
}
key = keyfile ? : x509 ?
key = params.keyfile ? : params.x509 ?
"/etc/keys/x509_evm.der" :
"/etc/keys/pubkey_evm.pem";
return verify_evm(file, key);
}
static int get_hash_algo_from_sig(unsigned char *sig)
{
uint8_t hashalgo;
if (sig[0] == 1) {
hashalgo = ((struct signature_hdr *)sig)->hash;
if (hashalgo >= DIGEST_ALGO_MAX)
return -1;
switch (hashalgo) {
case DIGEST_ALGO_SHA1:
return PKEY_HASH_SHA1;
case DIGEST_ALGO_SHA256:
return PKEY_HASH_SHA256;
default:
return -1;
}
} else if (sig[0] == 2) {
hashalgo = ((struct signature_v2_hdr *)sig)->hash_algo;
if (hashalgo >= PKEY_HASH__LAST)
return -1;
return hashalgo;
} else
return -1;
}
static int verify_signature(const char *file, unsigned char *sig, int siglen)
{
unsigned char hash[64];
int hashlen, sig_hash_algo;
char *key;
if (sig[0] != 0x03) {
log_err("security.ima has no signature\n");
return -1;
}
/* If user specified an hash algo on command line, let it override */
if (!user_hash_algo) {
sig_hash_algo = get_hash_algo_from_sig(sig + 1);
if (sig_hash_algo < 0) {
log_err("Invalid signature\n");
return -1;
}
/* Use hash algorithm as retrieved from signature */
hash_algo = pkey_hash_algo[sig_hash_algo];
}
hashlen = calc_hash(file, hash);
if (hashlen <= 1)
return hashlen;
/* Get signature type from sig header if user did not enforce it */
if (!user_sig_type) {
if (sig[1] == DIGSIG_VERSION_1)
verify_hash = verify_hash_v1;
else if (sig[1] == DIGSIG_VERSION_2) {
verify_hash = verify_hash_v2;
/* Read pubkey from x509 cert */
x509 = 1;
}
}
/* Determine what key to use for verification*/
key = keyfile ? : x509 ?
"/etc/keys/x509_evm.der" :
"/etc/keys/pubkey_evm.pem";
return verify_hash(hash, hashlen, sig + 1, siglen - 1, key);
}
static int verify_ima(const char *file)
{
unsigned char sig[1024];
@ -1432,7 +837,7 @@ static int verify_ima(const char *file)
free(tmp);
}
return verify_signature(file, sig, len);
return ima_verify_signature(file, sig, len);
}
static int cmd_verify_ima(struct command *cmd)
@ -1459,7 +864,7 @@ static int cmd_import(struct command *cmd)
inkey = g_argv[optind++];
if (!inkey) {
inkey = x509 ? "/etc/keys/x509_evm.der" :
inkey = params.x509 ? "/etc/keys/x509_evm.der" :
"/etc/keys/pubkey_evm.pem";
} else
ring = g_argv[optind++];
@ -1473,7 +878,7 @@ static int cmd_import(struct command *cmd)
if (!key)
return 1;
if (x509) {
if (params.x509) {
pub = file2bin(inkey, NULL, &len);
if (!pub)
goto out;
@ -1485,7 +890,7 @@ static int cmd_import(struct command *cmd)
log_info("Importing public key %s from file %s into keyring %d\n", name, inkey, id);
id = add_key(x509 ? "asymmetric" : "user", x509 ? NULL : name, pub, len, id);
id = add_key(params.x509 ? "asymmetric" : "user", params.x509 ? NULL : name, pub, len, id);
if (id < 0) {
log_err("add_key failed\n");
err = id;
@ -1493,7 +898,7 @@ static int cmd_import(struct command *cmd)
log_info("keyid: %d\n", id);
printf("%d\n", id);
}
if (x509)
if (params.x509)
free(pub);
out:
RSA_free(key);
@ -1644,7 +1049,7 @@ static int cmd_hmac_evm(struct command *cmd)
return -1;
}
key = keyfile ? : "/etc/keys/privkey_evm.pem";
key = params.keyfile ? : "/etc/keys/privkey_evm.pem";
if (digsig) {
err = sign_ima(file, key);
@ -1941,7 +1346,7 @@ void ima_ng_show(struct template_entry *entry)
if (sig) {
log_info(" ");
log_dump(sig, sig_len);
verify_signature(path, sig, sig_len);
ima_verify_signature(path, sig, sig_len);
} else
log_info("\n");
@ -2164,7 +1569,7 @@ int main(int argc, char *argv[])
g_argc = argc;
sign_hash = sign_hash_v1;
verify_hash = verify_hash_v1;
params.verify_hash = verify_hash_v1;
while (1) {
c = getopt_long(argc, argv, "hvnsda:p:fu::xk:t:r", opts, &lind);
@ -2177,7 +1582,7 @@ int main(int argc, char *argv[])
exit(0);
break;
case 'v':
verbose++;
params.verbose++;
break;
case 'd':
digest = 1;
@ -2191,8 +1596,8 @@ int main(int argc, char *argv[])
sigdump = 1;
break;
case 'a':
hash_algo = optarg;
user_hash_algo = 1;
params.hash_algo = optarg;
params.user_hash_algo = 1;
break;
case 'p':
keypass = optarg;
@ -2209,13 +1614,13 @@ int main(int argc, char *argv[])
uuid_str = optarg ?: "-";
break;
case 'x':
x509 = 1;
params.x509 = 1;
sign_hash = sign_hash_v2;
verify_hash = verify_hash_v2;
user_sig_type = 1;
params.verify_hash = verify_hash_v2;
params.user_sig_type = 1;
break;
case 'k':
keyfile = optarg;
params.keyfile = optarg;
break;
case 't':
search_type = optarg;

500
src/libevm.c
View File

@ -1,6 +1,502 @@
#include <libevm.h>
/*
* ima-evm-utils - IMA/EVM support utilities
*
* Copyright (C) 2011 Nokia Corporation
* Copyright (C) 2011,2012,2013 Intel Corporation
* Copyright (C) 2013,2014 Samsung Electronics
*
* Authors:
* Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
* <dmitry.kasatkin@intel.com>
* <d.kasatkin@samsung.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* File: libevm.c
* IMA/EVM library
*/
void ima_func(void)
/* should we use logger instead for library? */
#define USE_FPRINTF
#include "libevm.h"
const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
[PKEY_HASH_MD4] = "md4",
[PKEY_HASH_MD5] = "md5",
[PKEY_HASH_SHA1] = "sha1",
[PKEY_HASH_RIPE_MD_160] = "rmd160",
[PKEY_HASH_SHA256] = "sha256",
[PKEY_HASH_SHA384] = "sha384",
[PKEY_HASH_SHA512] = "sha512",
[PKEY_HASH_SHA224] = "sha224",
};
/*
* Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
*/
static const uint8_t RSA_digest_info_MD5[] = {
0x30, 0x20, 0x30, 0x0C, 0x06, 0x08,
0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */
0x05, 0x00, 0x04, 0x10
};
static const uint8_t RSA_digest_info_SHA1[] = {
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x0E, 0x03, 0x02, 0x1A,
0x05, 0x00, 0x04, 0x14
};
static const uint8_t RSA_digest_info_RIPE_MD_160[] = {
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x24, 0x03, 0x02, 0x01,
0x05, 0x00, 0x04, 0x14
};
static const uint8_t RSA_digest_info_SHA224[] = {
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
0x05, 0x00, 0x04, 0x1C
};
static const uint8_t RSA_digest_info_SHA256[] = {
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
0x05, 0x00, 0x04, 0x20
};
static const uint8_t RSA_digest_info_SHA384[] = {
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
0x05, 0x00, 0x04, 0x30
};
static const uint8_t RSA_digest_info_SHA512[] = {
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
0x05, 0x00, 0x04, 0x40
};
const struct RSA_ASN1_template RSA_ASN1_templates[PKEY_HASH__LAST] = {
#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) }
[PKEY_HASH_MD5] = _(MD5),
[PKEY_HASH_SHA1] = _(SHA1),
[PKEY_HASH_RIPE_MD_160] = _(RIPE_MD_160),
[PKEY_HASH_SHA256] = _(SHA256),
[PKEY_HASH_SHA384] = _(SHA384),
[PKEY_HASH_SHA512] = _(SHA512),
[PKEY_HASH_SHA224] = _(SHA224),
#undef _
};
struct libevm_params params = {
.verbose = LOG_INFO - 1,
.hash_algo = "sha1"
};
void do_dump(FILE *fp, const void *ptr, int len, bool cr)
{
int i;
uint8_t *data = (uint8_t *) ptr;
for (i = 0; i < len; i++)
fprintf(fp, "%02x", data[i]);
if (cr)
fprintf(fp, "\n");
}
void dump(const void *ptr, int len)
{
do_dump(stdout, ptr, len, true);
}
int get_filesize(const char *filename)
{
struct stat stats;
/* Need to know the file length */
stat(filename, &stats);
return (int)stats.st_size;
}
static inline int get_fdsize(int fd)
{
struct stat stats;
/* Need to know the file length */
fstat(fd, &stats);
return (int)stats.st_size;
}
static int add_file_hash(const char *file, EVP_MD_CTX *ctx)
{
uint8_t *data;
int err, size, bs = DATA_SIZE;
size_t len;
FILE *fp;
data = malloc(bs);
if (!data) {
log_err("malloc failed\n");
return -1;
}
fp = fopen(file, "r");
if (!fp) {
log_err("Unable to open %s\n", file);
return -1;
}
for (size = get_fdsize(fileno(fp)); size; size -= len) {
len = MIN(size, bs);
err = fread(data, len, 1, fp);
if (!err) {
if (ferror(fp)) {
log_err("fread() error\n\n");
return -1;
}
break;
}
err = EVP_DigestUpdate(ctx, data, len);
if (!err) {
log_err("EVP_DigestUpdate() failed\n");
return 1;
}
}
fclose(fp);
free(data);
return 0;
}
static int add_dir_hash(const char *file, EVP_MD_CTX *ctx)
{
int err;
struct dirent *de;
DIR *dir;
unsigned long long ino, off;
unsigned int type;
dir = opendir(file);
if (!dir) {
log_err("Unable to open %s\n", file);
return -1;
}
while ((de = readdir(dir))) {
ino = de->d_ino;
off = de->d_off;
type = de->d_type;
log_debug("entry: %s, ino: %llu, type: %u, off: %llu, reclen: %hu\n",
de->d_name, ino, type, off, de->d_reclen);
err = EVP_DigestUpdate(ctx, de->d_name, strlen(de->d_name));
/*err |= EVP_DigestUpdate(ctx, &off, sizeof(off));*/
err |= EVP_DigestUpdate(ctx, &ino, sizeof(ino));
err |= EVP_DigestUpdate(ctx, &type, sizeof(type));
if (!err) {
log_err("EVP_DigestUpdate() failed\n");
return 1;
}
}
closedir(dir);
return 0;
}
static int add_link_hash(const char *path, EVP_MD_CTX *ctx)
{
int err;
char buf[1024];
err = readlink(path, buf, sizeof(buf));
if (err <= 0)
return -1;
log_info("link: %s -> %.*s\n", path, err, buf);
return !EVP_DigestUpdate(ctx, buf, err);
}
static int add_dev_hash(struct stat *st, EVP_MD_CTX *ctx)
{
uint32_t dev = st->st_rdev;
unsigned major = (dev & 0xfff00) >> 8;
unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
log_info("device: %u:%u\n", major, minor);
return !EVP_DigestUpdate(ctx, &dev, sizeof(dev));
}
int ima_calc_hash(const char *file, uint8_t *hash)
{
struct stat st;
EVP_MD_CTX ctx;
const EVP_MD *md;
unsigned int mdlen;
int err;
/* Need to know the file length */
err = lstat(file, &st);
if (err < 0) {
log_err("stat() failed\n");
return err;
}
md = EVP_get_digestbyname(params.hash_algo);
if (!md) {
log_err("EVP_get_digestbyname() failed\n");
return 1;
}
err = EVP_DigestInit(&ctx, md);
if (!err) {
log_err("EVP_DigestInit() failed\n");
return 1;
}
switch (st.st_mode & S_IFMT) {
case S_IFREG:
err = add_file_hash(file, &ctx);
break;
case S_IFDIR:
err = add_dir_hash(file, &ctx);
break;
case S_IFLNK:
err = add_link_hash(file, &ctx);
break;
case S_IFIFO: case S_IFSOCK:
case S_IFCHR: case S_IFBLK:
err = add_dev_hash(&st, &ctx);
break;
default:
log_errno("Unsupported file type");
return -1;
}
if (err)
return err;
err = EVP_DigestFinal(&ctx, hash, &mdlen);
if (!err) {
log_err("EVP_DigestFinal() failed\n");
return 1;
}
return mdlen;
}
RSA *read_pub_key(const char *keyfile)
{
FILE *fp;
RSA *key = NULL;
X509 *crt = NULL;
EVP_PKEY *pkey = NULL;
fp = fopen(keyfile, "r");
if (!fp) {
log_err("Unable to open keyfile %s\n", keyfile);
return NULL;
}
if (params.x509) {
crt = d2i_X509_fp(fp, NULL);
if (!crt) {
log_err("d2i_X509_fp() failed\n");
goto out;
}
pkey = X509_extract_key(crt);
if (!pkey) {
log_err("X509_extract_key() failed\n");
goto out;
}
key = EVP_PKEY_get1_RSA(pkey);
} else {
key = PEM_read_RSA_PUBKEY(fp, NULL, NULL, NULL);
}
if (!key)
log_err("PEM_read_RSA_PUBKEY() failed\n");
out:
if (pkey)
EVP_PKEY_free(pkey);
if (crt)
X509_free(crt);
fclose(fp);
return key;
}
int verify_hash_v1(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile)
{
int err, len;
SHA_CTX ctx;
unsigned char out[1024];
RSA *key;
unsigned char sighash[20];
struct signature_hdr *hdr = (struct signature_hdr *)sig;
log_info("hash: ");
log_dump(hash, size);
key = read_pub_key(keyfile);
if (!key)
return 1;
SHA1_Init(&ctx);
SHA1_Update(&ctx, hash, size);
SHA1_Update(&ctx, hdr, sizeof(*hdr));
SHA1_Final(sighash, &ctx);
log_info("sighash: ");
log_dump(sighash, sizeof(sighash));
err = RSA_public_decrypt(siglen - sizeof(*hdr) - 2, sig + sizeof(*hdr) + 2, out, key, RSA_PKCS1_PADDING);
RSA_free(key);
if (err < 0) {
log_err("RSA_public_decrypt() failed: %d\n", err);
return 1;
}
len = err;
if (len != sizeof(sighash) || memcmp(out, sighash, len) != 0) {
log_err("Verification failed: %d\n", err);
return -1;
} else {
/*log_info("Verification is OK\n");*/
printf("Verification is OK\n");
}
return 0;
}
int verify_hash_v2(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile)
{
int err, len;
unsigned char out[1024];
RSA *key;
struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
const struct RSA_ASN1_template *asn1;
log_info("hash: ");
log_dump(hash, size);
key = read_pub_key(keyfile);
if (!key)
return 1;
err = RSA_public_decrypt(siglen - sizeof(*hdr), sig + sizeof(*hdr), out, key, RSA_PKCS1_PADDING);
RSA_free(key);
if (err < 0) {
log_err("RSA_public_decrypt() failed: %d\n", err);
return 1;
}
len = err;
asn1 = &RSA_ASN1_templates[hdr->hash_algo];
if (len < asn1->size || memcmp(out, asn1->data, asn1->size)) {
log_err("Verification failed: %d\n", err);
return -1;
}
len -= asn1->size;
if (len != size || memcmp(out + asn1->size, hash, len)) {
log_err("Verification failed: %d\n", err);
return -1;
}
/*log_info("Verification is OK\n");*/
printf("Verification is OK\n");
return 0;
}
int get_hash_algo(const char *algo)
{
int i;
for (i = 0; i < PKEY_HASH__LAST; i++)
if (!strcmp(algo, pkey_hash_algo[i]))
return i;
return PKEY_HASH_SHA1;
}
static int get_hash_algo_from_sig(unsigned char *sig)
{
uint8_t hashalgo;
if (sig[0] == 1) {
hashalgo = ((struct signature_hdr *)sig)->hash;
if (hashalgo >= DIGEST_ALGO_MAX)
return -1;
switch (hashalgo) {
case DIGEST_ALGO_SHA1:
return PKEY_HASH_SHA1;
case DIGEST_ALGO_SHA256:
return PKEY_HASH_SHA256;
default:
return -1;
}
} else if (sig[0] == 2) {
hashalgo = ((struct signature_v2_hdr *)sig)->hash_algo;
if (hashalgo >= PKEY_HASH__LAST)
return -1;
return hashalgo;
} else
return -1;
}
int ima_verify_signature(const char *file, unsigned char *sig, int siglen)
{
unsigned char hash[64];
int hashlen, sig_hash_algo;
char *key;
if (sig[0] != 0x03) {
log_err("security.ima has no signature\n");
return -1;
}
/* If user specified an hash algo on command line, let it override */
if (!params.user_hash_algo) {
sig_hash_algo = get_hash_algo_from_sig(sig + 1);
if (sig_hash_algo < 0) {
log_err("Invalid signature\n");
return -1;
}
/* Use hash algorithm as retrieved from signature */
params.hash_algo = pkey_hash_algo[sig_hash_algo];
}
hashlen = ima_calc_hash(file, hash);
if (hashlen <= 1)
return hashlen;
/* Get signature type from sig header if user did not enforce it */
if (!params.user_sig_type) {
if (sig[1] == DIGSIG_VERSION_1)
params.verify_hash = verify_hash_v1;
else if (sig[1] == DIGSIG_VERSION_2) {
params.verify_hash = verify_hash_v2;
/* Read pubkey from x509 cert */
params.x509 = 1;
}
}
/* Determine what key to use for verification*/
key = params.keyfile ? : params.x509 ?
"/etc/keys/x509_evm.der" :
"/etc/keys/pubkey_evm.pem";
return params.verify_hash(hash, hashlen, sig + 1, siglen - 1, key);
}

152
src/libevm.h
View File

@ -1,7 +1,157 @@
#ifndef _LIBEVM_H
#define _LIBEVM_H
void ima_func(void);
#include <sys/types.h>
#include <stdint.h>
#include <unistd.h>
#include <syslog.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <dirent.h>
#include <string.h>
#include <stdbool.h>
#include <openssl/sha.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/hmac.h>
#include <openssl/engine.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/x509.h>
#ifdef USE_FPRINTF
#define do_log(level, fmt, args...) ({ if (level <= params.verbose) fprintf(stderr, fmt, ##args); })
#define do_log_dump(level, p, len, cr) ({ if (level <= params.verbose) do_dump(stderr, p, len, cr); })
#else
#define do_log(level, fmt, args...) syslog(level, fmt, ##args)
#define do_log_dump(level, p, len, cr)
#endif
#ifdef DEBUG
#define log_debug(fmt, args...) do_log(LOG_DEBUG, "%s:%d " fmt, __func__ , __LINE__ , ##args)
#define log_debug_dump(p, len) do_log_dump(LOG_DEBUG, p, len, true)
#define log_debug_dump_n(p, len) do_log_dump(LOG_DEBUG, p, len, false)
#else
#define log_debug(fmt, args...)
#define log_debug_dump(p, len)
#endif
#define log_dump(p, len) do_log_dump(LOG_INFO, p, len, true)
#define log_dump_n(p, len) do_log_dump(LOG_INFO, p, len, false)
#define log_info(fmt, args...) do_log(LOG_INFO, fmt, ##args)
#define log_err(fmt, args...) do_log(LOG_ERR, fmt, ##args)
#define log_errno(fmt, args...) do_log(LOG_ERR, fmt ": errno: %s (%d)\n", ##args, strerror(errno), errno)
#define DATA_SIZE 4096
#define SHA1_HASH_LEN 20
#define EXT2_IOC_GETVERSION _IOR('v', 1, long)
#define EXT34_IOC_GETVERSION _IOR('f', 3, long)
#define FS_IOC_GETFLAGS _IOR('f', 1, long)
#define FS_IOC_SETFLAGS _IOW('f', 2, long)
#define FS_IOC32_GETFLAGS _IOR('f', 1, int)
#define FS_IOC32_SETFLAGS _IOW('f', 2, int)
#define __packed __attribute__((packed))
struct h_misc {
unsigned long ino;
uint32_t generation;
uid_t uid;
gid_t gid;
unsigned short mode;
} hmac_misc;
enum pubkey_algo {
PUBKEY_ALGO_RSA,
PUBKEY_ALGO_MAX,
};
enum digest_algo {
DIGEST_ALGO_SHA1,
DIGEST_ALGO_SHA256,
DIGEST_ALGO_MAX
};
enum digsig_version {
DIGSIG_VERSION_1 = 1,
DIGSIG_VERSION_2
};
struct pubkey_hdr {
uint8_t version; /* key format version */
uint32_t timestamp; /* key made, always 0 for now */
uint8_t algo;
uint8_t nmpi;
char mpi[0];
} __packed;
struct signature_hdr {
uint8_t version; /* signature format version */
uint32_t timestamp; /* signature made */
uint8_t algo;
uint8_t hash;
uint8_t keyid[8];
uint8_t nmpi;
char mpi[0];
} __packed;
enum pkey_hash_algo {
PKEY_HASH_MD4,
PKEY_HASH_MD5,
PKEY_HASH_SHA1,
PKEY_HASH_RIPE_MD_160,
PKEY_HASH_SHA256,
PKEY_HASH_SHA384,
PKEY_HASH_SHA512,
PKEY_HASH_SHA224,
PKEY_HASH__LAST
};
/*
* signature format v2 - for using with asymmetric keys
*/
struct signature_v2_hdr {
uint8_t version; /* signature format version */
uint8_t hash_algo; /* Digest algorithm [enum pkey_hash_algo] */
uint32_t keyid; /* IMA key identifier - not X509/PGP specific*/
uint16_t sig_size; /* signature size */
uint8_t sig[0]; /* signature payload */
} __packed;
typedef int (*verify_hash_fn_t)(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile);
struct libevm_params {
int verbose;
const char *hash_algo;
int user_hash_algo;
int user_sig_type;
int x509;
char *keyfile;
verify_hash_fn_t verify_hash;
};
struct RSA_ASN1_template {
const uint8_t *data;
size_t size;
};
extern const struct RSA_ASN1_template RSA_ASN1_templates[PKEY_HASH__LAST];
extern struct libevm_params params;
void do_dump(FILE *fp, const void *ptr, int len, bool cr);
void dump(const void *ptr, int len);
int get_filesize(const char *filename);
int ima_calc_hash(const char *file, uint8_t *hash);
int get_hash_algo(const char *algo);
RSA *read_pub_key(const char *keyfile);
int verify_hash_v1(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile);
int verify_hash_v2(const unsigned char *hash, int size, unsigned char *sig, int siglen, const char *keyfile);
int ima_verify_signature(const char *file, unsigned char *sig, int siglen);
#endif