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@xxxxxxxxxxxxx> --- .../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... ?
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