| Message ID | 20210504043357.4093409-2-vt@altlinux.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima-evm-utils: Add --keyid option | expand |
On 5/4/21 12:33 AM, Vitaly Chikunov wrote: > Allow user to set signature's keyid using `--keyid' option. Keyid should > correspond to SKID in certificate, when keyid is calculated using SHA-1 > in libimaevm it may mismatch keyid extracted by the kernel from SKID of > certificate (the way public key is presented to the kernel), thus making > signatures not verifiable. This may happen when certificate is using non > SHA-1 SKID (see rfc7093) or just 'unique number' (see rfc5280 4.2.1.2). > As a last resort user may specify arbitrary keyid using the new option. > > This commit creates backward compatible ABI change for libimaevm, > because of adding additional parameter to imaevm_params - older > libimaevm can work with newer client. > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org> > Reported-by: Elvira Khabirova <lineprinter0@gmail.com> > --- > README | 1 + > src/evmctl.c | 14 ++++++++++++++ > src/imaevm.h | 1 + > src/libimaevm.c | 8 +++++--- > tests/sign_verify.test | 1 + > 5 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/README b/README > index 321045d..8cd66e0 100644 > --- a/README > +++ b/README > @@ -48,6 +48,7 @@ OPTIONS > --xattr-user store xattrs in user namespace (for testing purposes) > --rsa use RSA key type and signing scheme v1 > -k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem) > + --keyid val overwrite signature keyid with a value (for signing) > -o, --portable generate portable EVM signatures > -p, --pass password for encrypted signing key > -r, --recursive recurse into directories (sign) > diff --git a/src/evmctl.c b/src/evmctl.c > index 1815f55..7983299 100644 > --- a/src/evmctl.c > +++ b/src/evmctl.c > @@ -2446,6 +2446,7 @@ static void usage(void) > " --xattr-user store xattrs in user namespace (for testing purposes)\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" > + " --keyid val overwrite signature keyid with a value (for signing)\n" > " -o, --portable generate portable EVM signatures\n" > " -p, --pass password for encrypted signing key\n" > " -r, --recursive recurse into directories (sign)\n" > @@ -2525,6 +2526,7 @@ static struct option opts[] = { > {"xattr-user", 0, 0, 140}, > {"ignore-violations", 0, 0, 141}, > {"pcrs", 1, 0, 142}, > + {"keyid", 1, 0, 143}, > {} > > }; > @@ -2569,6 +2571,8 @@ int main(int argc, char *argv[]) > { > int err = 0, c, lind; > ENGINE *eng = NULL; > + unsigned long int keyid; > + char *eptr; > > #if !(OPENSSL_VERSION_NUMBER < 0x10100000) > OPENSSL_init_crypto( > @@ -2713,6 +2717,16 @@ int main(int argc, char *argv[]) > } > pcrfile[npcrfile++] = optarg; > break; > + case 143: > + errno = 0; > + keyid = strtoul(optarg, &eptr, 16); > + if (errno || eptr - optarg != strlen(optarg) || > + keyid > UINT_MAX || keyid == 0) { > + log_err("Invalid keyid value.\n"); > + exit(1); > + } > + imaevm_params.keyid = keyid; > + break; > case '?': > exit(1); > break; > diff --git a/src/imaevm.h b/src/imaevm.h > index 4503919..9f38059 100644 > --- a/src/imaevm.h > +++ b/src/imaevm.h > @@ -196,6 +196,7 @@ struct libimaevm_params { > const char *hash_algo; > const char *keyfile; > const char *keypass; > + uint32_t keyid; /* keyid overriding value, unless 0. */ > }; > > struct RSA_ASN1_template { > diff --git a/src/libimaevm.c b/src/libimaevm.c > index fa6c278..481d29d 100644 > --- a/src/libimaevm.c > +++ b/src/libimaevm.c > @@ -45,6 +45,7 @@ > #include <sys/param.h> > #include <sys/stat.h> > #include <asm/byteorder.h> > +#include <arpa/inet.h> > #include <unistd.h> > #include <dirent.h> > #include <string.h> > @@ -894,7 +895,6 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, > const EVP_MD *md; > size_t sigsize; > const char *st; > - uint32_t keyid; > > if (!hash) { > log_err("sign_hash_v2: hash is null\n"); > @@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, > return -1; > } > > - calc_keyid_v2(&keyid, name, pkey); > - hdr->keyid = keyid; > + if (imaevm_params.keyid) > + hdr->keyid = htonl(imaevm_params.keyid); Nit: Since existing code uses __be32_to_cpup I would use __cpu_to_be32 here. > + else > + calc_keyid_v2(&hdr->keyid, name, pkey); > > st = "EVP_PKEY_CTX_new"; > if (!(ctx = EVP_PKEY_CTX_new(pkey, NULL))) > diff --git a/tests/sign_verify.test b/tests/sign_verify.test > index 288e133..2c21812 100755 > --- a/tests/sign_verify.test > +++ b/tests/sign_verify.test > @@ -359,6 +359,7 @@ sign_verify rsa1024 sha256 0x0301 --rsa > sign_verify rsa1024 md5 0x030201:K:0080 > sign_verify rsa1024 sha1 0x030202:K:0080 > sign_verify rsa1024 sha224 0x030207:K:0080 > +expect_pass check_sign TYPE=ima KEY=rsa1024 ALG=sha256 PREFIX=0x030204aabbccdd0080 OPTS=--keyid=aabbccdd > sign_verify rsa1024 sha256 0x030204:K:0080 > try_different_keys > try_different_sigs Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Stefan, On Tue, May 04, 2021 at 08:51:03AM -0400, Stefan Berger wrote: > > @@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, > > return -1; > > } > > - calc_keyid_v2(&keyid, name, pkey); > > - hdr->keyid = keyid; > > + if (imaevm_params.keyid) > > + hdr->keyid = htonl(imaevm_params.keyid); > > > Nit: Since existing code uses __be32_to_cpup I would use __cpu_to_be32 here. That __be32_to_cpup usage is highly dubious. Perhaps, it should be converted to some user-space and standard functions like be32toh(3). Even in the kernel you should use be32_to_cpup, not __be32_to_cpup. The "__" prefix is for a reason. Thanks, > > > > + else > > + calc_keyid_v2(&hdr->keyid, name, pkey); > > st = "EVP_PKEY_CTX_new"; > > if (!(ctx = EVP_PKEY_CTX_new(pkey, NULL))) > > diff --git a/tests/sign_verify.test b/tests/sign_verify.test > > index 288e133..2c21812 100755 > > --- a/tests/sign_verify.test > > +++ b/tests/sign_verify.test > > @@ -359,6 +359,7 @@ sign_verify rsa1024 sha256 0x0301 --rsa > > sign_verify rsa1024 md5 0x030201:K:0080 > > sign_verify rsa1024 sha1 0x030202:K:0080 > > sign_verify rsa1024 sha224 0x030207:K:0080 > > +expect_pass check_sign TYPE=ima KEY=rsa1024 ALG=sha256 PREFIX=0x030204aabbccdd0080 OPTS=--keyid=aabbccdd > > sign_verify rsa1024 sha256 0x030204:K:0080 > > try_different_keys > > try_different_sigs > > > Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
On Wed, May 05, 2021 at 02:18:04AM +0300, Vitaly Chikunov wrote: > Stefan, > > On Tue, May 04, 2021 at 08:51:03AM -0400, Stefan Berger wrote: > > > @@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, > > > return -1; > > > } > > > - calc_keyid_v2(&keyid, name, pkey); > > > - hdr->keyid = keyid; > > > + if (imaevm_params.keyid) > > > + hdr->keyid = htonl(imaevm_params.keyid); > > > > > > Nit: Since existing code uses __be32_to_cpup I would use __cpu_to_be32 here. > > That __be32_to_cpup usage is highly dubious. Perhaps, it should be > converted to some user-space and standard functions like be32toh(3). By the way, be32toh() is identical to ntohl(). I wonder what was the reason for the existing code to use these obscure linux-specific functions instead of posix interface described in byteorder(3)?
Dmitry, On Wed, May 05, 2021 at 02:43:18AM +0300, Dmitry V. Levin wrote: > On Wed, May 05, 2021 at 02:18:04AM +0300, Vitaly Chikunov wrote: > > Stefan, > > > > On Tue, May 04, 2021 at 08:51:03AM -0400, Stefan Berger wrote: > > > > @@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, > > > > return -1; > > > > } > > > > - calc_keyid_v2(&keyid, name, pkey); > > > > - hdr->keyid = keyid; > > > > + if (imaevm_params.keyid) > > > > + hdr->keyid = htonl(imaevm_params.keyid); > > > > > > > > > Nit: Since existing code uses __be32_to_cpup I would use __cpu_to_be32 here. > > > > That __be32_to_cpup usage is highly dubious. Perhaps, it should be > > converted to some user-space and standard functions like be32toh(3). > > By the way, be32toh() is identical to ntohl(). > > I wonder what was the reason for the existing code to use these obscure > linux-specific functions instead of posix interface described in > byteorder(3)? Perhaps, it's to simplify work with unaligned data, since __be32_to_cpup accepts the pointer (without assumption of alignment), where you cannot just call ntohl(*ptr) without possible sigbus on some platforms. linux/byteorder/generic.h: * The "... p" macros, like le64_to_cpup, can be used with pointers * to unaligned data, but there will be a performance penalty on * some architectures. Use get_unaligned for unaligned data. Thanks, > > > -- > ldv
diff --git a/README b/README index 321045d..8cd66e0 100644 --- a/README +++ b/README @@ -48,6 +48,7 @@ OPTIONS --xattr-user store xattrs in user namespace (for testing purposes) --rsa use RSA key type and signing scheme v1 -k, --key path to signing key (default: /etc/keys/{privkey,pubkey}_evm.pem) + --keyid val overwrite signature keyid with a value (for signing) -o, --portable generate portable EVM signatures -p, --pass password for encrypted signing key -r, --recursive recurse into directories (sign) diff --git a/src/evmctl.c b/src/evmctl.c index 1815f55..7983299 100644 --- a/src/evmctl.c +++ b/src/evmctl.c @@ -2446,6 +2446,7 @@ static void usage(void) " --xattr-user store xattrs in user namespace (for testing purposes)\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" + " --keyid val overwrite signature keyid with a value (for signing)\n" " -o, --portable generate portable EVM signatures\n" " -p, --pass password for encrypted signing key\n" " -r, --recursive recurse into directories (sign)\n" @@ -2525,6 +2526,7 @@ static struct option opts[] = { {"xattr-user", 0, 0, 140}, {"ignore-violations", 0, 0, 141}, {"pcrs", 1, 0, 142}, + {"keyid", 1, 0, 143}, {} }; @@ -2569,6 +2571,8 @@ int main(int argc, char *argv[]) { int err = 0, c, lind; ENGINE *eng = NULL; + unsigned long int keyid; + char *eptr; #if !(OPENSSL_VERSION_NUMBER < 0x10100000) OPENSSL_init_crypto( @@ -2713,6 +2717,16 @@ int main(int argc, char *argv[]) } pcrfile[npcrfile++] = optarg; break; + case 143: + errno = 0; + keyid = strtoul(optarg, &eptr, 16); + if (errno || eptr - optarg != strlen(optarg) || + keyid > UINT_MAX || keyid == 0) { + log_err("Invalid keyid value.\n"); + exit(1); + } + imaevm_params.keyid = keyid; + break; case '?': exit(1); break; diff --git a/src/imaevm.h b/src/imaevm.h index 4503919..9f38059 100644 --- a/src/imaevm.h +++ b/src/imaevm.h @@ -196,6 +196,7 @@ struct libimaevm_params { const char *hash_algo; const char *keyfile; const char *keypass; + uint32_t keyid; /* keyid overriding value, unless 0. */ }; struct RSA_ASN1_template { diff --git a/src/libimaevm.c b/src/libimaevm.c index fa6c278..481d29d 100644 --- a/src/libimaevm.c +++ b/src/libimaevm.c @@ -45,6 +45,7 @@ #include <sys/param.h> #include <sys/stat.h> #include <asm/byteorder.h> +#include <arpa/inet.h> #include <unistd.h> #include <dirent.h> #include <string.h> @@ -894,7 +895,6 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, const EVP_MD *md; size_t sigsize; const char *st; - uint32_t keyid; if (!hash) { log_err("sign_hash_v2: hash is null\n"); @@ -932,8 +932,10 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, return -1; } - calc_keyid_v2(&keyid, name, pkey); - hdr->keyid = keyid; + if (imaevm_params.keyid) + hdr->keyid = htonl(imaevm_params.keyid); + else + calc_keyid_v2(&hdr->keyid, name, pkey); st = "EVP_PKEY_CTX_new"; if (!(ctx = EVP_PKEY_CTX_new(pkey, NULL))) diff --git a/tests/sign_verify.test b/tests/sign_verify.test index 288e133..2c21812 100755 --- a/tests/sign_verify.test +++ b/tests/sign_verify.test @@ -359,6 +359,7 @@ sign_verify rsa1024 sha256 0x0301 --rsa sign_verify rsa1024 md5 0x030201:K:0080 sign_verify rsa1024 sha1 0x030202:K:0080 sign_verify rsa1024 sha224 0x030207:K:0080 +expect_pass check_sign TYPE=ima KEY=rsa1024 ALG=sha256 PREFIX=0x030204aabbccdd0080 OPTS=--keyid=aabbccdd sign_verify rsa1024 sha256 0x030204:K:0080 try_different_keys try_different_sigs
Allow user to set signature's keyid using `--keyid' option. Keyid should correspond to SKID in certificate, when keyid is calculated using SHA-1 in libimaevm it may mismatch keyid extracted by the kernel from SKID of certificate (the way public key is presented to the kernel), thus making signatures not verifiable. This may happen when certificate is using non SHA-1 SKID (see rfc7093) or just 'unique number' (see rfc5280 4.2.1.2). As a last resort user may specify arbitrary keyid using the new option. This commit creates backward compatible ABI change for libimaevm, because of adding additional parameter to imaevm_params - older libimaevm can work with newer client. Signed-off-by: Vitaly Chikunov <vt@altlinux.org> Reported-by: Elvira Khabirova <lineprinter0@gmail.com> --- README | 1 + src/evmctl.c | 14 ++++++++++++++ src/imaevm.h | 1 + src/libimaevm.c | 8 +++++--- tests/sign_verify.test | 1 + 5 files changed, 22 insertions(+), 3 deletions(-)