| Message ID | 20210504043357.4093409-4-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 to have certificate appended to the private key of `--key' > specified (PEM) file (for v2 signing) to facilitate reading of keyid > from the associated cert. This will allow users to have private and > public key as a single file. There is no check that public key form the > cert matches associated private key. > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org> > --- > README | 2 ++ > src/libimaevm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 49 insertions(+), 3 deletions(-) > > diff --git a/README b/README > index 0e1f6ba..2c21ba6 100644 > --- a/README > +++ b/README > @@ -127,6 +127,8 @@ for signing and importing the key. > Second key format uses X509 DER encoded public key certificates and uses asymmetric key support > in the kernel (since kernel 3.9). CONFIG_INTEGRITY_ASYMMETRIC_KEYS must be enabled (default). > > +For v2 signatures x509 certificate with the public key could be appended to the private > +key (both are in PEM format) to properly determine its Subject Key Identifier SKID. > > Integrity keyrings > ---------------- > diff --git a/src/libimaevm.c b/src/libimaevm.c > index 481d29d..3607a76 100644 > --- a/src/libimaevm.c > +++ b/src/libimaevm.c > @@ -57,6 +57,7 @@ > #include <openssl/pem.h> > #include <openssl/evp.h> > #include <openssl/x509.h> > +#include <openssl/x509v3.h> > #include <openssl/err.h> > > #include "imaevm.h" > @@ -748,6 +749,47 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey) > X509_PUBKEY_free(pk); > } > > +/* Try to read keyid from key file (in case it have appended cert). */ > +static int read_keyid(const char *keyfile, uint32_t *keyid) > +{ So the private key is assumed to be in PEM format. I suppose if there's an appended X509 in the private key file as well then only one function should be necessary to extract the x509 cert from the files. That function should be able to handle PEM and DER format at the same time. Have you tried extracting the x509 cert from the private key file using that other function in 2/3 yet?
Stefan, On Tue, May 04, 2021 at 09:38:06AM -0400, Stefan Berger wrote: > On 5/4/21 12:33 AM, Vitaly Chikunov wrote: > > Allow to have certificate appended to the private key of `--key' > > specified (PEM) file (for v2 signing) to facilitate reading of keyid > > from the associated cert. This will allow users to have private and > > public key as a single file. There is no check that public key form the > > cert matches associated private key. > > > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org> > > --- > > README | 2 ++ > > src/libimaevm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- > > 2 files changed, 49 insertions(+), 3 deletions(-) > > > > diff --git a/README b/README > > index 0e1f6ba..2c21ba6 100644 > > --- a/README > > +++ b/README > > @@ -127,6 +127,8 @@ for signing and importing the key. > > Second key format uses X509 DER encoded public key certificates and uses asymmetric key support > > in the kernel (since kernel 3.9). CONFIG_INTEGRITY_ASYMMETRIC_KEYS must be enabled (default). > > +For v2 signatures x509 certificate with the public key could be appended to the private > > +key (both are in PEM format) to properly determine its Subject Key Identifier SKID. > > Integrity keyrings > > ---------------- > > diff --git a/src/libimaevm.c b/src/libimaevm.c > > index 481d29d..3607a76 100644 > > --- a/src/libimaevm.c > > +++ b/src/libimaevm.c > > @@ -57,6 +57,7 @@ > > #include <openssl/pem.h> > > #include <openssl/evp.h> > > #include <openssl/x509.h> > > +#include <openssl/x509v3.h> > > #include <openssl/err.h> > > #include "imaevm.h" > > @@ -748,6 +749,47 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey) > > X509_PUBKEY_free(pk); > > } > > +/* Try to read keyid from key file (in case it have appended cert). */ > > +static int read_keyid(const char *keyfile, uint32_t *keyid) > > +{ > > So the private key is assumed to be in PEM format. Yes, even though README says something different. > I suppose if there's an > appended X509 in the private key file as well then only one function should > be necessary to extract the x509 cert from the files. That function should > be able to handle PEM and DER format at the same time. Have you tried > extracting the x509 cert from the private key file using that other function > in 2/3 yet? Excuse me, I don't understand what you talking about in this note. 2/3 does not read private keys. Where and why should be one function? And what other function? Thanks,
On 5/4/21 6:27 PM, Vitaly Chikunov wrote: > Stefan, > > On Tue, May 04, 2021 at 09:38:06AM -0400, Stefan Berger wrote: >> On 5/4/21 12:33 AM, Vitaly Chikunov wrote: >>> Allow to have certificate appended to the private key of `--key' >>> specified (PEM) file (for v2 signing) to facilitate reading of keyid >>> from the associated cert. This will allow users to have private and >>> public key as a single file. There is no check that public key form the >>> cert matches associated private key. >>> >>> Signed-off-by: Vitaly Chikunov <vt@altlinux.org> >>> --- >>> README | 2 ++ >>> src/libimaevm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- >>> 2 files changed, 49 insertions(+), 3 deletions(-) >>> >>> diff --git a/README b/README >>> index 0e1f6ba..2c21ba6 100644 >>> --- a/README >>> +++ b/README >>> @@ -127,6 +127,8 @@ for signing and importing the key. >>> Second key format uses X509 DER encoded public key certificates and uses asymmetric key support >>> in the kernel (since kernel 3.9). CONFIG_INTEGRITY_ASYMMETRIC_KEYS must be enabled (default). >>> +For v2 signatures x509 certificate with the public key could be appended to the private >>> +key (both are in PEM format) to properly determine its Subject Key Identifier SKID. >>> Integrity keyrings >>> ---------------- >>> diff --git a/src/libimaevm.c b/src/libimaevm.c >>> index 481d29d..3607a76 100644 >>> --- a/src/libimaevm.c >>> +++ b/src/libimaevm.c >>> @@ -57,6 +57,7 @@ >>> #include <openssl/pem.h> >>> #include <openssl/evp.h> >>> #include <openssl/x509.h> >>> +#include <openssl/x509v3.h> >>> #include <openssl/err.h> >>> #include "imaevm.h" >>> @@ -748,6 +749,47 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey) >>> X509_PUBKEY_free(pk); >>> } >>> +/* Try to read keyid from key file (in case it have appended cert). */ >>> +static int read_keyid(const char *keyfile, uint32_t *keyid) >>> +{ >> So the private key is assumed to be in PEM format. > Yes, even though README says something different. > >> I suppose if there's an >> appended X509 in the private key file as well then only one function should >> be necessary to extract the x509 cert from the files. That function should >> be able to handle PEM and DER format at the same time. Have you tried >> extracting the x509 cert from the private key file using that other function >> in 2/3 yet? > Excuse me, I don't understand what you talking about in this note. > 2/3 does not read private keys. Where and why should be one function? > And what other function? It should be possible to combine your functions extract_keyid (2/3) and read_keyid (3/3) into a single function that can handle PEM files containing X509 certs as well as DER files. It's two times very similar code and the function that can handle DER and PEM should be able to handle PEM files with private keys + X509 certs. Stefan > Thanks, >
Stefan, On Tue, May 04, 2021 at 09:04:44PM -0400, Stefan Berger wrote: > On 5/4/21 6:27 PM, Vitaly Chikunov wrote: > > On Tue, May 04, 2021 at 09:38:06AM -0400, Stefan Berger wrote: > > > On 5/4/21 12:33 AM, Vitaly Chikunov wrote: > > > > Allow to have certificate appended to the private key of `--key' > > > > specified (PEM) file (for v2 signing) to facilitate reading of keyid > > > > from the associated cert. This will allow users to have private and > > > > public key as a single file. There is no check that public key form the > > > > cert matches associated private key. > > > > > > > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org> > > > > --- > > > > README | 2 ++ > > > > src/libimaevm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- > > > > 2 files changed, 49 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/README b/README > > > > index 0e1f6ba..2c21ba6 100644 > > > > --- a/README > > > > +++ b/README > > > > @@ -127,6 +127,8 @@ for signing and importing the key. > > > > Second key format uses X509 DER encoded public key certificates and uses asymmetric key support > > > > in the kernel (since kernel 3.9). CONFIG_INTEGRITY_ASYMMETRIC_KEYS must be enabled (default). > > > > +For v2 signatures x509 certificate with the public key could be appended to the private > > > > +key (both are in PEM format) to properly determine its Subject Key Identifier SKID. > > > > Integrity keyrings > > > > ---------------- > > > > diff --git a/src/libimaevm.c b/src/libimaevm.c > > > > index 481d29d..3607a76 100644 > > > > --- a/src/libimaevm.c > > > > +++ b/src/libimaevm.c > > > > @@ -57,6 +57,7 @@ > > > > #include <openssl/pem.h> > > > > #include <openssl/evp.h> > > > > #include <openssl/x509.h> > > > > +#include <openssl/x509v3.h> > > > > #include <openssl/err.h> > > > > #include "imaevm.h" > > > > @@ -748,6 +749,47 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey) > > > > X509_PUBKEY_free(pk); > > > > } > > > > +/* Try to read keyid from key file (in case it have appended cert). */ > > > > +static int read_keyid(const char *keyfile, uint32_t *keyid) > > > > +{ > > > So the private key is assumed to be in PEM format. > > Yes, even though README says something different. > > > > > I suppose if there's an > > > appended X509 in the private key file as well then only one function should > > > be necessary to extract the x509 cert from the files. That function should > > > be able to handle PEM and DER format at the same time. Have you tried > > > extracting the x509 cert from the private key file using that other function > > > in 2/3 yet? > > Excuse me, I don't understand what you talking about in this note. > > 2/3 does not read private keys. Where and why should be one function? > > And what other function? > > It should be possible to combine your functions extract_keyid (2/3) and > read_keyid (3/3) into a single function that can handle PEM files containing > X509 certs as well as DER files. It's two times very similar code and the > function that can handle DER and PEM should be able to handle PEM files with > private keys + X509 certs. I see. There should be very generic function that can read fd, FILE, bio, and memory region, also can parse DER, PEM, and combined PEMs. Thanks,
Stefan, On Wed, May 05, 2021 at 04:15:02AM +0300, Vitaly Chikunov wrote: > On Tue, May 04, 2021 at 09:04:44PM -0400, Stefan Berger wrote: > > On 5/4/21 6:27 PM, Vitaly Chikunov wrote: > > > On Tue, May 04, 2021 at 09:38:06AM -0400, Stefan Berger wrote: > > > > On 5/4/21 12:33 AM, Vitaly Chikunov wrote: > > > > I suppose if there's an > > > > appended X509 in the private key file as well then only one function should > > > > be necessary to extract the x509 cert from the files. That function should > > > > be able to handle PEM and DER format at the same time. Have you tried > > > > extracting the x509 cert from the private key file using that other function > > > > in 2/3 yet? > > > Excuse me, I don't understand what you talking about in this note. > > > 2/3 does not read private keys. Where and why should be one function? > > > And what other function? > > > > It should be possible to combine your functions extract_keyid (2/3) and > > read_keyid (3/3) into a single function that can handle PEM files containing > > X509 certs as well as DER files. It's two times very similar code and the > > function that can handle DER and PEM should be able to handle PEM files with > > private keys + X509 certs. > > I see. There should be very generic function that can read fd, FILE, > bio, and memory region, also can parse DER, PEM, and combined PEMs. Implemented in [PATCH v3 2/3], but now there are some problems. ima_read_keyid() is called with different intentions from evmctl and from libimaevm. Call from evmctl is explicit user intention (to read cert) and should produce error messages for failures. Call from calc_keyid_v2() is best effort (and can be thought as a side effect) and should be as quiet as possible. Also, in the second case it shall not try to load DER certificate. Vitaly,
diff --git a/README b/README index 0e1f6ba..2c21ba6 100644 --- a/README +++ b/README @@ -127,6 +127,8 @@ for signing and importing the key. Second key format uses X509 DER encoded public key certificates and uses asymmetric key support in the kernel (since kernel 3.9). CONFIG_INTEGRITY_ASYMMETRIC_KEYS must be enabled (default). +For v2 signatures x509 certificate with the public key could be appended to the private +key (both are in PEM format) to properly determine its Subject Key Identifier SKID. Integrity keyrings ---------------- diff --git a/src/libimaevm.c b/src/libimaevm.c index 481d29d..3607a76 100644 --- a/src/libimaevm.c +++ b/src/libimaevm.c @@ -57,6 +57,7 @@ #include <openssl/pem.h> #include <openssl/evp.h> #include <openssl/x509.h> +#include <openssl/x509v3.h> #include <openssl/err.h> #include "imaevm.h" @@ -748,6 +749,47 @@ void calc_keyid_v2(uint32_t *keyid, char *str, EVP_PKEY *pkey) X509_PUBKEY_free(pk); } +/* Try to read keyid from key file (in case it have appended cert). */ +static int read_keyid(const char *keyfile, uint32_t *keyid) +{ + int skid_len; + const ASN1_OCTET_STRING *skid; + X509 *x = NULL; + FILE *fp; + + fp = fopen(keyfile, "r"); + if (!fp) { + log_err("Failed to open keyfile: %s\n", keyfile); + return 0; + } + if (!PEM_read_X509(fp, &x, NULL, NULL)) { + long error = ERR_GET_REASON(ERR_peek_last_error()); + + if (error == PEM_R_NO_START_LINE) { + log_debug("No cert in keyfile %s\n", keyfile); + ERR_clear_error(); + } else { + log_err("Error reading cert from keyfile %s: %s\n", + keyfile, ERR_reason_error_string(error)); + } + fclose(fp); + return 0; + } + fclose(fp); + if (!(skid = X509_get0_subject_key_id(x))) + return 0; + skid_len = ASN1_STRING_length(skid); + if (skid_len < sizeof(keyid)) + return 0; + /* keyid is the last 4 bytes of SKID. */ + memcpy(keyid, ASN1_STRING_get0_data(skid) + skid_len - sizeof(*keyid), + sizeof(*keyid)); + log_debug("keyid: "); + log_debug_dump(keyid, 4); + return 1; + +} + static EVP_PKEY *read_priv_pkey(const char *keyfile, const char *keypass) { FILE *fp; @@ -932,10 +974,12 @@ static int sign_hash_v2(const char *algo, const unsigned char *hash, return -1; } - if (imaevm_params.keyid) + if (imaevm_params.keyid) { hdr->keyid = htonl(imaevm_params.keyid); - else - calc_keyid_v2(&hdr->keyid, name, pkey); + } else { + if (!read_keyid(keyfile, &hdr->keyid)) + calc_keyid_v2(&hdr->keyid, name, pkey); + } st = "EVP_PKEY_CTX_new"; if (!(ctx = EVP_PKEY_CTX_new(pkey, NULL)))
Allow to have certificate appended to the private key of `--key' specified (PEM) file (for v2 signing) to facilitate reading of keyid from the associated cert. This will allow users to have private and public key as a single file. There is no check that public key form the cert matches associated private key. Signed-off-by: Vitaly Chikunov <vt@altlinux.org> --- README | 2 ++ src/libimaevm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 49 insertions(+), 3 deletions(-)