11 Commits
v1.0 ... next

Author SHA1 Message Date
4928548d9d Add support for portable EVM format
Add a --portable argument that generates EVM signatures without using
the inode number and generation or fs UUID.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

Changelog:
- immutable and portable flags are exclusive, prevent enabling both.
2017-11-16 15:02:40 -05:00
233dedffe9 Write out .sig file as security.ima xattr
To write the .sig file as security.ima xattr using setfattr first
requires converting the .sig file from binary to ascii-hex.  Although
this conversion can be done using hexdump, it is unnecessary when
calling setxattr.  This patch defines a new command called
"ima_setxattr", which calls lsetxattr() to write the .sig file as
the security.ima xattr.

Changelog:
- remove unnecessary copy
- fixed --sigfile option

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2016-03-06 07:55:04 -05:00
3e2a67bdb0 script to build static evmctl version
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
2015-10-01 22:42:45 +03:00
839a674580 Supply file attributes values on command line
Can be used by Android filesystem image creation tool.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
2015-09-20 23:28:20 +03:00
e55d286ad6 Use single flag to indicate 'no'flag
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
2015-09-20 23:15:32 +03:00
28d99354de Use byte range values
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
2015-09-20 22:22:06 +03:00
ea5ccdf38f Newer kernels requires at least 64 byte keys
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
2015-09-20 22:22:00 +03:00
b0d13ba557 calc_evm_hmac/hash: avoid fd leak when ioctl fails
When opening the file succeeds but ioctl() then fails, the file must
be closed before returning.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
2015-09-09 23:02:01 +03:00
199311e6a5 ima_verify: ignore -n flag
"evmutil ima_verify -n <some file>" disabled using xattrs without enabling
using a signature file, resulting in the use of uninitialized memory in
ima_verify_signature() and thus unpredictable results.

Such a mode of operation makes no sense, so interpret -n as
documented ("print result to stdout instead of setting xattr") and ignore it
during ima_verify. Instead, switch between the two verification modes only
via the global sigfile variable.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
2015-09-09 22:50:45 +03:00
453d3db8a5 tpm_pcr_read: close file when returning early
When return from inside the for() loop, the open file was not
closed.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
2015-09-09 22:50:35 +03:00
fa0b30b15e add_dir_hash: fix DIR leak in case of failure
When bailing out of the function due to EVP_DigestUpdate()
failing, the DIR resources allocated with opendir() were
not freed.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
2015-09-09 22:50:18 +03:00
5 changed files with 227 additions and 54 deletions

8
README
View File

@ -26,7 +26,7 @@ COMMANDS
--version
help <command>
import [--rsa] pubkey keyring
sign [-r] [--imahash | --imasig ] [--key key] [--pass password] file
sign [-r] [--imahash | --imasig ] [--portable] [--key key] [--pass password] file
verify file
ima_sign [--sigfile] [--key key] [--pass password] file
ima_verify file
@ -46,6 +46,7 @@ OPTIONS
-f, --sigfile store IMA signature in .sig file instead of xattr
--rsa use RSA key type and signing scheme v1
-k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem)
-o, --portable generate portable EVM signatures
-p, --pass password for encrypted signing key
-r, --recursive recurse into directories (sign)
-t, --type file types to fix 'fdsxm' (f: file, d: directory, s: block/char/symlink)
@ -95,7 +96,8 @@ Kernel configuration option CONFIG_EVM_ATTR_FSUUID controls whether to include
filesystem UUID into HMAC and enabled by default. Therefore evmctl also includes
fsuuid by default. Providing '--uuid' option without parameter allows to disable
usage of fs uuid. Providing '--uuid=UUID' option with parameter allows to use
custom UUID.
custom UUID. Providing the '--portable' option will disable usage of the fs uuid
and also the inode number and generation.
Kernel configuration option CONFIG_EVM_EXTRA_SMACK_XATTRS controls whether to
include additional SMACK extended attributes into HMAC. They are following:
@ -142,7 +144,7 @@ EVM encrypted key is used for EVM HMAC calculation:
keyctl pipe `keyctl search @u user kmk` > /etc/keys/kmk
# create the EVM encrypted key
keyctl add encrypted evm-key "new user:kmk 32" @u
keyctl add encrypted evm-key "new user:kmk 64" @u
keyctl pipe `keyctl search @u encrypted evm-key` >/etc/keys/evm-key

4
build-static.sh Executable file
View File

@ -0,0 +1,4 @@
#!/bin/sh
gcc -static -o evmctl.static -include config.h src/evmctl.c src/libimaevm.c -lcrypto -lkeyutils -ldl

View File

@ -104,15 +104,25 @@ static int digest;
static int digsig;
static int sigfile;
static char *uuid_str;
static char *ino_str;
static char *uid_str;
static char *gid_str;
static char *mode_str;
static char *generation_str;
static char *caps_str;
static char *ima_str;
static char *selinux_str;
static char *search_type;
static int recursive;
static int msize;
static dev_t fs_dev;
static bool evm_immutable;
static bool evm_portable;
#define HMAC_FLAG_UUID 0x0001
#define HMAC_FLAG_UUID_SET 0x0002
static unsigned long hmac_flags = HMAC_FLAG_UUID;
#define HMAC_FLAG_NO_UUID 0x0001
#define HMAC_FLAG_CAPS_SET 0x0002
static unsigned long hmac_flags;
typedef int (*find_cb_t)(const char *path);
static int find(const char *path, int dts, find_cb_t func);
@ -200,7 +210,7 @@ static int hex_to_bin(char ch)
return -1;
}
static int hex2bin(uint8_t *dst, const char *src, size_t count)
static int hex2bin(void *dst, const char *src, size_t count)
{
int hi, lo;
@ -214,7 +224,7 @@ static int hex2bin(uint8_t *dst, const char *src, size_t count)
if ((hi < 0) || (lo < 0))
return -1;
*dst++ = (hi << 4) | lo;
*(uint8_t *)dst++ = (hi << 4) | lo;
}
return 0;
}
@ -275,7 +285,7 @@ static int get_uuid(struct stat *st, char *uuid)
FILE *fp;
size_t len;
if (hmac_flags & HMAC_FLAG_UUID_SET)
if (uuid_str)
return pack_uuid(uuid_str, uuid);
dev = st->st_dev;
@ -320,10 +330,21 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
return -1;
}
if (generation_str)
generation = strtoul(generation_str, NULL, 10);
if (ino_str)
st.st_ino = strtoul(ino_str, NULL, 10);
if (uid_str)
st.st_uid = strtoul(uid_str, NULL, 10);
if (gid_str)
st.st_gid = strtoul(gid_str, NULL, 10);
if (mode_str)
st.st_mode = strtoul(mode_str, NULL, 10);
if (!evm_immutable) {
if (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode)) {
/* we cannot at the momement to get generation of special files..
* kernel API does not support it */
if ((S_ISREG(st.st_mode) || S_ISDIR(st.st_mode)) && !generation_str) {
/* we cannot at the momement to get generation of
special files kernel API does not support it */
int fd = open(file, 0);
if (fd < 0) {
@ -332,6 +353,7 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
}
if (ioctl(fd, FS_IOC_GETVERSION, &generation)) {
log_err("ioctl() failed\n");
close(fd);
return -1;
}
close(fd);
@ -352,6 +374,18 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
}
for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
if (!strcmp(*xattrname, XATTR_NAME_SELINUX) && selinux_str) {
strcpy(xattr_value, selinux_str);
err = strlen(selinux_str) + 1;
} else if (!strcmp(*xattrname, XATTR_NAME_IMA) && ima_str) {
hex2bin(xattr_value, ima_str, strlen(ima_str) / 2);
err = strlen(ima_str) / 2;
} else if (!strcmp(*xattrname, XATTR_NAME_CAPS) && (hmac_flags & HMAC_FLAG_CAPS_SET)) {
if (!caps_str)
continue;
strcpy(xattr_value, caps_str);
err = strlen(caps_str);
} else {
err = lgetxattr(file, *xattrname, xattr_value, sizeof(xattr_value));
if (err < 0) {
log_info("no xattr: %s\n", *xattrname);
@ -361,6 +395,7 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
log_info("skipping xattr: %s\n", *xattrname);
continue;
}
}
/*log_debug("name: %s, value: %s, size: %d\n", *xattrname, xattr_value, err);*/
log_info("name: %s, size: %d\n", *xattrname, err);
log_debug_dump(xattr_value, err);
@ -384,8 +419,10 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
struct h_misc *hmac = (struct h_misc *)&hmac_misc;
hmac_size = sizeof(*hmac);
if (!evm_portable) {
hmac->ino = st.st_ino;
hmac->generation = generation;
}
hmac->uid = st.st_uid;
hmac->gid = st.st_gid;
hmac->mode = st.st_mode;
@ -393,8 +430,10 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
struct h_misc_64 *hmac = (struct h_misc_64 *)&hmac_misc;
hmac_size = sizeof(*hmac);
if (!evm_portable) {
hmac->ino = st.st_ino;
hmac->generation = generation;
}
hmac->uid = st.st_uid;
hmac->gid = st.st_gid;
hmac->mode = st.st_mode;
@ -402,8 +441,10 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
struct h_misc_32 *hmac = (struct h_misc_32 *)&hmac_misc;
hmac_size = sizeof(*hmac);
if (!evm_portable) {
hmac->ino = st.st_ino;
hmac->generation = generation;
}
hmac->uid = st.st_uid;
hmac->gid = st.st_gid;
hmac->mode = st.st_mode;
@ -418,7 +459,8 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
return 1;
}
if (!evm_immutable && (hmac_flags & HMAC_FLAG_UUID)) {
if (!evm_immutable && !evm_portable &&
!(hmac_flags & HMAC_FLAG_NO_UUID)) {
err = get_uuid(&st, uuid);
if (err)
return -1;
@ -455,6 +497,9 @@ static int sign_evm(const char *file, const char *key)
/* add header */
len++;
if (evm_portable)
sig[0] = EVM_XATTR_PORTABLE_DIGSIG;
else
sig[0] = EVM_IMA_XATTR_DIGSIG;
if (evm_immutable)
@ -734,19 +779,17 @@ static int verify_ima(const char *file)
unsigned char sig[1024];
int len;
if (xattr) {
len = lgetxattr(file, "security.ima", sig, sizeof(sig));
if (len < 0) {
log_err("getxattr failed: %s\n", file);
return len;
}
}
if (sigfile) {
void *tmp = file2bin(file, "sig", &len);
memcpy(sig, tmp, len);
free(tmp);
} else {
len = lgetxattr(file, "security.ima", sig, sizeof(sig));
if (len < 0) {
log_err("getxattr failed: %s\n", file);
return len;
}
}
return ima_verify_signature(file, sig, len);
@ -765,6 +808,37 @@ static int cmd_verify_ima(struct command *cmd)
return verify_ima(file);
}
static int cmd_convert(struct command *cmd)
{
char *inkey;
unsigned char _pub[1024], *pub = _pub;
int len, err = 0;
char name[20];
uint8_t keyid[8];
RSA *key;
params.x509 = 0;
inkey = g_argv[optind++];
if (!inkey) {
inkey = params.x509 ? "/etc/keys/x509_evm.der" :
"/etc/keys/pubkey_evm.pem";
}
key = read_pub_key(inkey, params.x509);
if (!key)
return 1;
len = key2bin(key, pub);
calc_keyid_v1(keyid, name, pub, len);
bin2file(inkey, "bin", pub, len);
bin2file(inkey, "keyid", (const unsigned char *)name, strlen(name));
RSA_free(key);
return err;
}
static int cmd_import(struct command *cmd)
{
char *inkey, *ring = NULL;
@ -837,6 +911,42 @@ out:
return err;
}
static int setxattr_ima(const char *file, char *sig_file)
{
unsigned char *sig;
int len, err;
if (sig_file)
sig = file2bin(sig_file, NULL, &len);
else
sig = file2bin(file, "sig", &len);
if (!sig)
return 0;
err = lsetxattr(file, "security.ima", sig, len, 0);
if (err < 0)
log_err("setxattr failed: %s\n", file);
free(sig);
return err;
}
static int cmd_setxattr_ima(struct command *cmd)
{
char *file, *sig = NULL;
if (sigfile)
sig = g_argv[optind++];
file = g_argv[optind++];
if (!file) {
log_err("Parameters missing\n");
print_usage(cmd);
return -1;
}
return setxattr_ima(file, sig);
}
#define MAX_KEY_SIZE 128
static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *hash)
@ -887,6 +997,7 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
}
if (ioctl(fd, FS_IOC_GETVERSION, &generation)) {
log_err("ioctl() failed\n");
close(fd);
goto out;
}
close(fd);
@ -1143,6 +1254,7 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
{
FILE *fp;
char *p, pcr_str[7], buf[70]; /* length of the TPM string */
int result = -1;
sprintf(pcr_str, "PCR-%d", idx);
@ -1158,11 +1270,12 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
break;
if (!strncmp(p, pcr_str, 6)) {
hex2bin(pcr, p + 7, len);
return 0;
result = 0;
break;
}
}
fclose(fp);
return -1;
return result;
}
#define TCG_EVENT_NAME_LEN_MAX 255
@ -1450,6 +1563,7 @@ static void usage(void)
" -f, --sigfile store IMA signature in .sig file instead of xattr\n"
" --rsa use RSA key type and signing scheme v1\n"
" -k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem)\n"
" -o, --portable generate portable EVM signatures\n"
" -p, --pass password for encrypted signing key\n"
" -r, --recursive recurse into directories (sign)\n"
" -t, --type file types to fix 'fdsxm' (f: file, d: directory, s: block/char/symlink)\n"
@ -1460,6 +1574,14 @@ static void usage(void)
" --smack use extra SMACK xattrs for EVM\n"
" --m32 force EVM hmac/signature for 32 bit target system\n"
" --m64 force EVM hmac/signature for 64 bit target system\n"
" --ino use custom inode for EVM\n"
" --uid use custom UID for EVM\n"
" --gid use custom GID for EVM\n"
" --mode use custom Mode for EVM\n"
" --generation use custom Generation for EVM(unspecified: from FS, empty: use 0)\n"
" --ima use custom IMA signature for EVM\n"
" --selinux use custom Selinux label for EVM\n"
" --caps use custom Capabilities for EVM(unspecified: from FS, empty: do not use)\n"
" -v increase verbosity level\n"
" -h, --help display this help and exit\n"
"\n");
@ -1469,10 +1591,12 @@ struct command cmds[] = {
{"--version", NULL, 0, ""},
{"help", cmd_help, 0, "<command>"},
{"import", cmd_import, 0, "[--rsa] pubkey keyring", "Import public key into the keyring.\n"},
{"convert", cmd_convert, 0, "key", "convert public key into the keyring.\n"},
{"sign", cmd_sign_evm, 0, "[-r] [--imahash | --imasig ] [--key key] [--pass [password] file", "Sign file metadata.\n"},
{"verify", cmd_verify_evm, 0, "file", "Verify EVM signature (for debugging).\n"},
{"ima_sign", cmd_sign_ima, 0, "[--sigfile] [--key key] [--pass [password] file", "Make file content signature.\n"},
{"ima_verify", cmd_verify_ima, 0, "file", "Verify IMA signature (for debugging).\n"},
{"ima_setxattr", cmd_setxattr_ima, 0, "[--sigfile file]", "Set IMA signature from sigfile\n"},
{"ima_hash", cmd_hash_ima, 0, "file", "Make file content hash.\n"},
{"ima_measurement", cmd_ima_measurement, 0, "file", "Verify measurement list (experimental).\n"},
{"ima_fix", cmd_ima_fix, 0, "[-t fdsxm] path", "Recursively fix IMA/EVM xattrs in fix mode.\n"},
@ -1498,8 +1622,17 @@ static struct option opts[] = {
{"recursive", 0, 0, 'r'},
{"m32", 0, 0, '3'},
{"m64", 0, 0, '6'},
{"smack", 0, 0, 256},
{"version", 0, 0, 257},
{"portable", 0, 0, 'o'},
{"smack", 0, 0, 128},
{"version", 0, 0, 129},
{"inode", 1, 0, 130},
{"uid", 1, 0, 131},
{"gid", 1, 0, 132},
{"mode", 1, 0, 133},
{"generation", 1, 0, 134},
{"ima", 1, 0, 135},
{"selinux", 1, 0, 136},
{"caps", 2, 0, 137},
{}
};
@ -1546,7 +1679,7 @@ int main(int argc, char *argv[])
g_argc = argc;
while (1) {
c = getopt_long(argc, argv, "hvnsda:p::fu::k:t:ri", opts, &lind);
c = getopt_long(argc, argv, "hvnsda:op::fu::k:t:ri", opts, &lind);
if (c == -1)
break;
@ -1580,14 +1713,11 @@ int main(int argc, char *argv[])
break;
case 'f':
sigfile = 1;
xattr = 0;
break;
case 'u':
uuid_str = optarg;
if (uuid_str)
hmac_flags |= HMAC_FLAG_UUID_SET;
else
hmac_flags &= ~HMAC_FLAG_UUID;
if (!uuid_str)
hmac_flags |= HMAC_FLAG_NO_UUID;
break;
case '1':
params.x509 = 0;
@ -1596,8 +1726,17 @@ int main(int argc, char *argv[])
params.keyfile = optarg;
break;
case 'i':
if (evm_portable)
log_err("Portable and immutable options are exclusive, ignoring immutable option.");
else
evm_immutable = true;
break;
case 'o':
if (evm_immutable)
log_err("Portable and immutable options are exclusive, ignoring portable option.");
else
evm_portable = true;
break;
case 't':
search_type = optarg;
break;
@ -1610,13 +1749,38 @@ int main(int argc, char *argv[])
case '6':
msize = 64;
break;
case 256:
case 128:
evm_config_xattrnames = evm_extra_smack_xattrs;
break;
case 257:
case 129:
printf("evmctl %s\n", VERSION);
exit(0);
break;
case 130:
ino_str = optarg;
break;
case 131:
uid_str = optarg;
break;
case 132:
gid_str = optarg;
break;
case 133:
mode_str = optarg;
break;
case 134:
generation_str = optarg;
break;
case 135:
ima_str = optarg;
break;
case 136:
selinux_str = optarg;
break;
case 137:
caps_str = optarg;
hmac_flags |= HMAC_FLAG_CAPS_SET;
break;
case '?':
exit(1);
break;

View File

@ -82,6 +82,7 @@ enum evm_ima_xattr_type {
EVM_XATTR_HMAC,
EVM_IMA_XATTR_DIGSIG,
IMA_XATTR_DIGEST_NG,
EVM_XATTR_PORTABLE_DIGSIG,
};
struct h_misc {

View File

@ -214,6 +214,7 @@ static int add_dir_hash(const char *file, EVP_MD_CTX *ctx)
DIR *dir;
unsigned long long ino, off;
unsigned int type;
int result = 0;
dir = opendir(file);
if (!dir) {
@ -233,13 +234,14 @@ static int add_dir_hash(const char *file, EVP_MD_CTX *ctx)
err |= EVP_DigestUpdate(ctx, &type, sizeof(type));
if (!err) {
log_err("EVP_DigestUpdate() failed\n");
return 1;
result = 1;
break;
}
}
closedir(dir);
return 0;
return result;
}
static int add_link_hash(const char *path, EVP_MD_CTX *ctx)
@ -373,7 +375,7 @@ int verify_hash_v1(const unsigned char *hash, int size, unsigned char *sig, int
unsigned char sighash[20];
struct signature_hdr *hdr = (struct signature_hdr *)sig;
log_info("hash: ");
log_info("hash-v1: ");
log_dump(hash, size);
key = read_pub_key(keyfile, 0);
@ -587,7 +589,7 @@ void calc_keyid_v1(uint8_t *keyid, char *str, const unsigned char *pkey, int len
id = __be64_to_cpup((__be64 *) keyid);
sprintf(str, "%llX", (unsigned long long)id);
log_info("keyid: %s\n", str);
log_info("keyid-v1: %s\n", str);
}
void calc_keyid_v2(uint32_t *keyid, char *str, RSA *key)
@ -719,7 +721,7 @@ int sign_hash_v1(const char *hashalgo, const unsigned char *hash, int size, cons
blen = (uint16_t *) (sig + sizeof(*hdr));
*blen = __cpu_to_be16(len << 3);
len += sizeof(*hdr) + 2;
log_info("evm/ima signature: %d bytes\n", len);
log_info("evm/ima signature-v1: %d bytes\n", len);
out:
RSA_free(key);
return len;