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authorTushar Sugandhi <tusharsu@linux.microsoft.com>2021-01-08 07:07:05 +0300
committerMimi Zohar <zohar@linux.ibm.com>2021-01-15 07:41:34 +0300
commit47d76a4840501c1cefb3fbce777a86c58b02532b (patch)
treed16d7373c43b3fb57e59b25c6461909517861ec1 /security
parentc4e43aa2eeb0cffcf0b17e0a60a9d212de9c49df (diff)
downloadlinux-47d76a4840501c1cefb3fbce777a86c58b02532b.tar.xz
IMA: limit critical data measurement based on a label
Integrity critical data may belong to a single subsystem or it may arise from cross subsystem interaction. Currently there is no mechanism to group or limit the data based on certain label. Limiting and grouping critical data based on a label would make it flexible and configurable to measure. Define "label:=", a new IMA policy condition, for the IMA func CRITICAL_DATA to allow grouping and limiting measurement of integrity critical data. Limit the measurement to the labels that are specified in the IMA policy - CRITICAL_DATA+"label:=". If "label:=" is not provided with the func CRITICAL_DATA, measure all the input integrity critical data. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/ima/ima_policy.c37
1 files changed, 34 insertions, 3 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 96ba4273c4d0..2c9db2d0b434 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -34,6 +34,7 @@
#define IMA_PCR 0x0100
#define IMA_FSNAME 0x0200
#define IMA_KEYRINGS 0x0400
+#define IMA_LABEL 0x0800
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -85,6 +86,7 @@ struct ima_rule_entry {
} lsm[MAX_LSM_RULES];
char *fsname;
struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
+ struct ima_rule_opt_list *label; /* Measure data grouped under this label */
struct ima_template_desc *template;
};
@@ -479,7 +481,11 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule,
opt_list = rule->keyrings;
break;
case CRITICAL_DATA:
- return true;
+ if (!rule->label)
+ return true;
+
+ opt_list = rule->label;
+ break;
default:
return false;
}
@@ -924,7 +930,7 @@ enum {
Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
Opt_appraise_type, Opt_appraise_flag,
Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
- Opt_err
+ Opt_label, Opt_err
};
static const match_table_t policy_tokens = {
@@ -961,6 +967,7 @@ static const match_table_t policy_tokens = {
{Opt_pcr, "pcr=%s"},
{Opt_template, "template=%s"},
{Opt_keyrings, "keyrings=%s"},
+ {Opt_label, "label=%s"},
{Opt_err, NULL}
};
@@ -1128,7 +1135,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
if (entry->action & ~(MEASURE | DONT_MEASURE))
return false;
- if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR))
+ if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
+ IMA_LABEL))
return false;
if (ima_rule_contains_lsm_cond(entry))
@@ -1338,6 +1346,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
entry->flags |= IMA_KEYRINGS;
break;
+ case Opt_label:
+ ima_log_string(ab, "label", args[0].from);
+
+ if (entry->label) {
+ result = -EINVAL;
+ break;
+ }
+
+ entry->label = ima_alloc_rule_opt_list(args);
+ if (IS_ERR(entry->label)) {
+ result = PTR_ERR(entry->label);
+ entry->label = NULL;
+ break;
+ }
+
+ entry->flags |= IMA_LABEL;
+ break;
case Opt_fsuuid:
ima_log_string(ab, "fsuuid", args[0].from);
@@ -1718,6 +1743,12 @@ int ima_policy_show(struct seq_file *m, void *v)
seq_puts(m, " ");
}
+ if (entry->flags & IMA_LABEL) {
+ seq_puts(m, "label=");
+ ima_show_rule_opt_list(m, entry->label);
+ seq_puts(m, " ");
+ }
+
if (entry->flags & IMA_PCR) {
snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
seq_printf(m, pt(Opt_pcr), tbuf);