| Message ID | 20220429112601.1421947-5-zohar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima: support fs-verity digests and signatures | expand |
On 4/29/22 07:25, Mimi Zohar wrote: > In preparation to differentiate between unsigned regular IMA file > hashes and fs-verity's file digests in the IMA measurement list, > define a new template field named 'd-ngv2'. > > Also define two new templates named 'ima-ngv2' and 'ima-sigv2', which > include the new 'd-ngv2' field. > > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> > --- > .../admin-guide/kernel-parameters.txt | 3 +- > Documentation/security/IMA-templates.rst | 4 + > security/integrity/ima/ima_template.c | 4 + > security/integrity/ima/ima_template_lib.c | 79 ++++++++++++++++--- > security/integrity/ima/ima_template_lib.h | 4 + > 5 files changed, 82 insertions(+), 12 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 3f1cc5e317ed..5e866be89f5d 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1903,7 +1903,8 @@ > > ima_template= [IMA] > Select one of defined IMA measurements template formats. > - Formats: { "ima" | "ima-ng" | "ima-sig" } > + Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" | > + "ima-sigv2" } > Default: "ima-ng" > > ima_template_fmt= > diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst > index cab97f49971d..eafc4e34f890 100644 > --- a/Documentation/security/IMA-templates.rst > +++ b/Documentation/security/IMA-templates.rst > @@ -67,6 +67,8 @@ descriptors by adding their identifier to the format string > - 'n': the name of the event (i.e. the file name), with size up to 255 bytes; > - 'd-ng': the digest of the event, calculated with an arbitrary hash > algorithm (field format: <hash algo>:digest); > + - 'd-ngv2': same as d-ng, but prefixed with the "ima" digest type > + (field format: <digest type>:<hash algo>:digest); > - 'd-modsig': the digest of the event without the appended modsig; > - 'n-ng': the name of the event, without size limitations; > - 'sig': the file signature, or the EVM portable signature if the file > @@ -87,7 +89,9 @@ Below, there is the list of defined template descriptors: > > - "ima": its format is ``d|n``; > - "ima-ng" (default): its format is ``d-ng|n-ng``; > + - "ima-ngv2": its format is ``d-ngv2|n-ng``; > - "ima-sig": its format is ``d-ng|n-ng|sig``; > + - "ima-sigv2": its format is ``d-ngv2|n-ng|sig``; > - "ima-buf": its format is ``d-ng|n-ng|buf``; > - "ima-modsig": its format is ``d-ng|n-ng|sig|d-modsig|modsig``; > - "evm-sig": its format is ``d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode``; > diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c > index db1ad6d7a57f..c25079faa208 100644 > --- a/security/integrity/ima/ima_template.c > +++ b/security/integrity/ima/ima_template.c > @@ -20,6 +20,8 @@ static struct ima_template_desc builtin_templates[] = { > {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT}, > {.name = "ima-ng", .fmt = "d-ng|n-ng"}, > {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"}, > + {.name = "ima-ngv2", .fmt = "d-ngv2|n-ng"}, > + {.name = "ima-sigv2", .fmt = "d-ngv2|n-ng|sig"}, > {.name = "ima-buf", .fmt = "d-ng|n-ng|buf"}, > {.name = "ima-modsig", .fmt = "d-ng|n-ng|sig|d-modsig|modsig"}, > {.name = "evm-sig", > @@ -38,6 +40,8 @@ static const struct ima_template_field supported_fields[] = { > .field_show = ima_show_template_string}, > {.field_id = "d-ng", .field_init = ima_eventdigest_ng_init, > .field_show = ima_show_template_digest_ng}, > + {.field_id = "d-ngv2", .field_init = ima_eventdigest_ngv2_init, > + .field_show = ima_show_template_digest_ngv2}, > {.field_id = "n-ng", .field_init = ima_eventname_ng_init, > .field_show = ima_show_template_string}, > {.field_id = "sig", .field_init = ima_eventsig_init, > diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c > index 4b6706f864d4..ff82e699149c 100644 > --- a/security/integrity/ima/ima_template_lib.c > +++ b/security/integrity/ima/ima_template_lib.c > @@ -24,11 +24,22 @@ static bool ima_template_hash_algo_allowed(u8 algo) > enum data_formats { > DATA_FMT_DIGEST = 0, > DATA_FMT_DIGEST_WITH_ALGO, > + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, > DATA_FMT_STRING, > DATA_FMT_HEX, > DATA_FMT_UINT > }; > > +enum digest_type { > + DIGEST_TYPE_IMA, > + DIGEST_TYPE__LAST > +}; > + > +#define DIGEST_TYPE_NAME_LEN_MAX 4 /* including NULL */ You probably mean 'NUL' ('\0') here: https://man7.org/linux/man-pages/man7/ascii.7.html > +static const char * const digest_type_name[DIGEST_TYPE__LAST] = { > + [DIGEST_TYPE_IMA] = "ima" > +}; > + > static int ima_write_template_field_data(const void *data, const u32 datalen, > enum data_formats datafmt, > struct ima_field_data *field_data) > @@ -72,8 +83,9 @@ static void ima_show_template_data_ascii(struct seq_file *m, > u32 buflen = field_data->len; > > switch (datafmt) { > + case DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: > case DATA_FMT_DIGEST_WITH_ALGO: > - buf_ptr = strnchr(field_data->data, buflen, ':'); > + buf_ptr = strrchr(field_data->data, ':'); > if (buf_ptr != field_data->data) > seq_printf(m, "%s", field_data->data); > > @@ -178,6 +190,14 @@ void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show, > field_data); > } > > +void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show, > + struct ima_field_data *field_data) > +{ > + ima_show_template_field_data(m, show, > + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, > + field_data); > +} > + > void ima_show_template_string(struct seq_file *m, enum ima_show_type show, > struct ima_field_data *field_data) > { > @@ -265,28 +285,38 @@ int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp, > } > > static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize, > - u8 hash_algo, > + u8 digest_type, u8 hash_algo, > struct ima_field_data *field_data) > { > /* > * digest formats: > * - DATA_FMT_DIGEST: digest > * - DATA_FMT_DIGEST_WITH_ALGO: <hash algo> + ':' + '\0' + digest, > + * - DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: > + * <digest type> + ':' + <hash algo> + ':' + '\0' + digest, > * > * where 'DATA_FMT_DIGEST' is the original digest format ('d') > * with a hash size limitation of 20 bytes, > + * where <digest type> is "ima", > * where <hash algo> is the hash_algo_name[] string. > */ > - u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 }; > + u8 buffer[DIGEST_TYPE_NAME_LEN_MAX + CRYPTO_MAX_ALG_NAME + 2 + > + IMA_MAX_DIGEST_SIZE] = { 0 }; > enum data_formats fmt = DATA_FMT_DIGEST; > u32 offset = 0; > > - if (hash_algo < HASH_ALGO__LAST) { > + if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) { > + fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO; > + offset += 1 + sprintf(buffer, "%*s:%*s:", > + (int)strlen(digest_type_name[digest_type]), > + digest_type_name[digest_type], > + (int)strlen(hash_algo_name[hash_algo]), > + hash_algo_name[hash_algo]); '%*s' seems to be for right-alignment but only makes sense if the length indicator is different than then following string. sprintf(buffer, "|%*s|",5,"test") prints | test|. Otherwise it seems to behave like plain '%s' in this case... ?
On Fri, 2022-04-29 at 11:09 -0400, Stefan Berger wrote: > > - if (hash_algo < HASH_ALGO__LAST) { > > + if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) { > > + fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO; > > + offset += 1 + sprintf(buffer, "%*s:%*s:", > > + (int)strlen(digest_type_name[digest_type]), > > + digest_type_name[digest_type], > > + (int)strlen(hash_algo_name[hash_algo]), > > + hash_algo_name[hash_algo]); > > '%*s' seems to be for right-alignment but only makes sense if the length > indicator is different than then following string. sprintf(buffer, > "|%*s|",5,"test") prints | test|. Otherwise it seems to behave like > plain '%s' in this case... ? Re-testing now, it works properly without the length. thanks, Mimi
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3f1cc5e317ed..5e866be89f5d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1903,7 +1903,8 @@ ima_template= [IMA] Select one of defined IMA measurements template formats. - Formats: { "ima" | "ima-ng" | "ima-sig" } + Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" | + "ima-sigv2" } Default: "ima-ng" ima_template_fmt= diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst index cab97f49971d..eafc4e34f890 100644 --- a/Documentation/security/IMA-templates.rst +++ b/Documentation/security/IMA-templates.rst @@ -67,6 +67,8 @@ descriptors by adding their identifier to the format string - 'n': the name of the event (i.e. the file name), with size up to 255 bytes; - 'd-ng': the digest of the event, calculated with an arbitrary hash algorithm (field format: <hash algo>:digest); + - 'd-ngv2': same as d-ng, but prefixed with the "ima" digest type + (field format: <digest type>:<hash algo>:digest); - 'd-modsig': the digest of the event without the appended modsig; - 'n-ng': the name of the event, without size limitations; - 'sig': the file signature, or the EVM portable signature if the file @@ -87,7 +89,9 @@ Below, there is the list of defined template descriptors: - "ima": its format is ``d|n``; - "ima-ng" (default): its format is ``d-ng|n-ng``; + - "ima-ngv2": its format is ``d-ngv2|n-ng``; - "ima-sig": its format is ``d-ng|n-ng|sig``; + - "ima-sigv2": its format is ``d-ngv2|n-ng|sig``; - "ima-buf": its format is ``d-ng|n-ng|buf``; - "ima-modsig": its format is ``d-ng|n-ng|sig|d-modsig|modsig``; - "evm-sig": its format is ``d-ng|n-ng|evmsig|xattrnames|xattrlengths|xattrvalues|iuid|igid|imode``; diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index db1ad6d7a57f..c25079faa208 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -20,6 +20,8 @@ static struct ima_template_desc builtin_templates[] = { {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT}, {.name = "ima-ng", .fmt = "d-ng|n-ng"}, {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"}, + {.name = "ima-ngv2", .fmt = "d-ngv2|n-ng"}, + {.name = "ima-sigv2", .fmt = "d-ngv2|n-ng|sig"}, {.name = "ima-buf", .fmt = "d-ng|n-ng|buf"}, {.name = "ima-modsig", .fmt = "d-ng|n-ng|sig|d-modsig|modsig"}, {.name = "evm-sig", @@ -38,6 +40,8 @@ static const struct ima_template_field supported_fields[] = { .field_show = ima_show_template_string}, {.field_id = "d-ng", .field_init = ima_eventdigest_ng_init, .field_show = ima_show_template_digest_ng}, + {.field_id = "d-ngv2", .field_init = ima_eventdigest_ngv2_init, + .field_show = ima_show_template_digest_ngv2}, {.field_id = "n-ng", .field_init = ima_eventname_ng_init, .field_show = ima_show_template_string}, {.field_id = "sig", .field_init = ima_eventsig_init, diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c index 4b6706f864d4..ff82e699149c 100644 --- a/security/integrity/ima/ima_template_lib.c +++ b/security/integrity/ima/ima_template_lib.c @@ -24,11 +24,22 @@ static bool ima_template_hash_algo_allowed(u8 algo) enum data_formats { DATA_FMT_DIGEST = 0, DATA_FMT_DIGEST_WITH_ALGO, + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, DATA_FMT_STRING, DATA_FMT_HEX, DATA_FMT_UINT }; +enum digest_type { + DIGEST_TYPE_IMA, + DIGEST_TYPE__LAST +}; + +#define DIGEST_TYPE_NAME_LEN_MAX 4 /* including NULL */ +static const char * const digest_type_name[DIGEST_TYPE__LAST] = { + [DIGEST_TYPE_IMA] = "ima" +}; + static int ima_write_template_field_data(const void *data, const u32 datalen, enum data_formats datafmt, struct ima_field_data *field_data) @@ -72,8 +83,9 @@ static void ima_show_template_data_ascii(struct seq_file *m, u32 buflen = field_data->len; switch (datafmt) { + case DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: case DATA_FMT_DIGEST_WITH_ALGO: - buf_ptr = strnchr(field_data->data, buflen, ':'); + buf_ptr = strrchr(field_data->data, ':'); if (buf_ptr != field_data->data) seq_printf(m, "%s", field_data->data); @@ -178,6 +190,14 @@ void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show, field_data); } +void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data) +{ + ima_show_template_field_data(m, show, + DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO, + field_data); +} + void ima_show_template_string(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data) { @@ -265,28 +285,38 @@ int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp, } static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize, - u8 hash_algo, + u8 digest_type, u8 hash_algo, struct ima_field_data *field_data) { /* * digest formats: * - DATA_FMT_DIGEST: digest * - DATA_FMT_DIGEST_WITH_ALGO: <hash algo> + ':' + '\0' + digest, + * - DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO: + * <digest type> + ':' + <hash algo> + ':' + '\0' + digest, * * where 'DATA_FMT_DIGEST' is the original digest format ('d') * with a hash size limitation of 20 bytes, + * where <digest type> is "ima", * where <hash algo> is the hash_algo_name[] string. */ - u8 buffer[CRYPTO_MAX_ALG_NAME + 2 + IMA_MAX_DIGEST_SIZE] = { 0 }; + u8 buffer[DIGEST_TYPE_NAME_LEN_MAX + CRYPTO_MAX_ALG_NAME + 2 + + IMA_MAX_DIGEST_SIZE] = { 0 }; enum data_formats fmt = DATA_FMT_DIGEST; u32 offset = 0; - if (hash_algo < HASH_ALGO__LAST) { + if (digest_type < DIGEST_TYPE__LAST && hash_algo < HASH_ALGO__LAST) { + fmt = DATA_FMT_DIGEST_WITH_TYPE_AND_ALGO; + offset += 1 + sprintf(buffer, "%*s:%*s:", + (int)strlen(digest_type_name[digest_type]), + digest_type_name[digest_type], + (int)strlen(hash_algo_name[hash_algo]), + hash_algo_name[hash_algo]); + } else if (hash_algo < HASH_ALGO__LAST) { fmt = DATA_FMT_DIGEST_WITH_ALGO; - offset += snprintf(buffer, CRYPTO_MAX_ALG_NAME + 1, "%s", - hash_algo_name[hash_algo]); - buffer[offset] = ':'; - offset += 2; + offset += 1 + sprintf(buffer, "%*s:", + (int)strlen(hash_algo_name[hash_algo]), + hash_algo_name[hash_algo]); } if (digest) @@ -361,7 +391,8 @@ int ima_eventdigest_init(struct ima_event_data *event_data, cur_digestsize = hash.hdr.length; out: return ima_eventdigest_init_common(cur_digest, cur_digestsize, - HASH_ALGO__LAST, field_data); + DIGEST_TYPE__LAST, HASH_ALGO__LAST, + field_data); } /* @@ -382,7 +413,32 @@ int ima_eventdigest_ng_init(struct ima_event_data *event_data, hash_algo = event_data->iint->ima_hash->algo; out: return ima_eventdigest_init_common(cur_digest, cur_digestsize, - hash_algo, field_data); + DIGEST_TYPE__LAST, hash_algo, + field_data); +} + +/* + * This function writes the digest of an event (without size limit), + * prefixed with both the digest type and hash algorithm. + */ +int ima_eventdigest_ngv2_init(struct ima_event_data *event_data, + struct ima_field_data *field_data) +{ + u8 *cur_digest = NULL, hash_algo = ima_hash_algo; + u32 cur_digestsize = 0; + u8 digest_type = DIGEST_TYPE_IMA; + + if (event_data->violation) /* recording a violation. */ + goto out; + + cur_digest = event_data->iint->ima_hash->digest; + cur_digestsize = event_data->iint->ima_hash->length; + + hash_algo = event_data->iint->ima_hash->algo; +out: + return ima_eventdigest_init_common(cur_digest, cur_digestsize, + digest_type, hash_algo, + field_data); } /* @@ -417,7 +473,8 @@ int ima_eventdigest_modsig_init(struct ima_event_data *event_data, } return ima_eventdigest_init_common(cur_digest, cur_digestsize, - hash_algo, field_data); + DIGEST_TYPE__LAST, hash_algo, + field_data); } static int ima_eventname_init_common(struct ima_event_data *event_data, diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h index c71f1de95753..9f7c335f304f 100644 --- a/security/integrity/ima/ima_template_lib.h +++ b/security/integrity/ima/ima_template_lib.h @@ -21,6 +21,8 @@ void ima_show_template_digest(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data); void ima_show_template_digest_ng(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data); +void ima_show_template_digest_ngv2(struct seq_file *m, enum ima_show_type show, + struct ima_field_data *field_data); void ima_show_template_string(struct seq_file *m, enum ima_show_type show, struct ima_field_data *field_data); void ima_show_template_sig(struct seq_file *m, enum ima_show_type show, @@ -38,6 +40,8 @@ int ima_eventname_init(struct ima_event_data *event_data, struct ima_field_data *field_data); int ima_eventdigest_ng_init(struct ima_event_data *event_data, struct ima_field_data *field_data); +int ima_eventdigest_ngv2_init(struct ima_event_data *event_data, + struct ima_field_data *field_data); int ima_eventdigest_modsig_init(struct ima_event_data *event_data, struct ima_field_data *field_data); int ima_eventname_ng_init(struct ima_event_data *event_data,
In preparation to differentiate between unsigned regular IMA file hashes and fs-verity's file digests in the IMA measurement list, define a new template field named 'd-ngv2'. Also define two new templates named 'ima-ngv2' and 'ima-sigv2', which include the new 'd-ngv2' field. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> --- .../admin-guide/kernel-parameters.txt | 3 +- Documentation/security/IMA-templates.rst | 4 + security/integrity/ima/ima_template.c | 4 + security/integrity/ima/ima_template_lib.c | 79 ++++++++++++++++--- security/integrity/ima/ima_template_lib.h | 4 + 5 files changed, 82 insertions(+), 12 deletions(-)