From: Roberto Sassu roberto.sassu@huawei.com
euleros inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I7QZ2M CVE: NA
-------------------------------------------------
IMA-Measure creates a new measurement entry every time a file is measured, unless the same entry is already in the measurement list.
This patch introduces a new type of measurement list, recognizable by the PCR number specified with the new ima_digest_list_pcr= kernel option. This type of measurement list includes measurements of digest lists and files not found in those lists.
The benefit of this patch is the availability of a predictable PCR that can be used to seal data or TPM keys to the OS software. Unlike standard measurements, digest list measurements only indicate that files with a digest in those lists could have been accessed, but not if and when. With standard measurements, however, the chosen PCR is unlikely predictable.
Both standard and digest list measurements can be generated at the same time by adding '+' as a prefix to the value of ima_digest_list_pcr= (example: with ima_digest_list_pcr=+11, IMA generates standard measurements with PCR 10 and digest list measurements with PCR 11).
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com Signed-off-by: Tianxing Zhang zhangtianxing3@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Signed-off-by: zhoushuiqing zhoushuiqing2@huawei.com --- .../admin-guide/kernel-parameters.txt | 9 ++++ security/integrity/ima/ima.h | 9 ++-- security/integrity/ima/ima_api.c | 42 +++++++++++++++---- security/integrity/ima/ima_digest_list.c | 25 +++++++++++ security/integrity/ima/ima_init.c | 2 +- security/integrity/ima/ima_main.c | 18 +++++++- security/integrity/ima/ima_policy.c | 3 +- security/integrity/integrity.h | 1 + 8 files changed, 95 insertions(+), 14 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ee50a3b91d73..b1e74fa1431a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1953,6 +1953,15 @@ Use the canonical format for the binary runtime measurements, instead of host native format.
+ ima_digest_list_pcr= + [IMA] + Specify which PCR is extended when file digests are + not found in the loaded digest lists. If '+' is not + specified, no measurement entry is created if the + digest is found. Otherwise, IMA creates also entries + with PCR 10, according to the existing behavior. + Format: { [+]<unsigned int> } + ima_hash= [IMA] Format: { md5 | sha1 | rmd160 | sha256 | sha384 | sha512 | ... } diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 6df0cd6cdd6b..8030bd78e4c2 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -56,6 +56,8 @@ extern int ima_hash_algo_idx __ro_after_init; extern int ima_extra_slots __ro_after_init; extern int ima_appraise; extern struct tpm_chip *ima_tpm_chip; +extern int ima_digest_list_pcr; +extern bool ima_plus_standard_pcr; extern const char boot_aggregate_name[]; extern int ima_digest_list_actions;
@@ -270,7 +272,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, const unsigned char *filename, struct evm_ima_xattr_data *xattr_value, int xattr_len, const struct modsig *modsig, int pcr, - struct ima_template_desc *template_desc); + struct ima_template_desc *template_desc, + struct ima_digest *digest); int process_buffer_measurement(struct mnt_idmap *idmap, struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, @@ -282,8 +285,8 @@ int ima_alloc_init_template(struct ima_event_data *event_data, struct ima_template_entry **entry, struct ima_template_desc *template_desc); int ima_store_template(struct ima_template_entry *entry, int violation, - struct inode *inode, - const unsigned char *filename, int pcr); + struct inode *inode, const unsigned char *filename, + int pcr, struct ima_digest *digest); void ima_free_template_entry(struct ima_template_entry *entry); const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index d3662f4acadc..c5b92b99a4b4 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -102,11 +102,13 @@ int ima_alloc_init_template(struct ima_event_data *event_data, */ int ima_store_template(struct ima_template_entry *entry, int violation, struct inode *inode, - const unsigned char *filename, int pcr) + const unsigned char *filename, int pcr, + struct ima_digest *digest) { static const char op[] = "add_template_measure"; static const char audit_cause[] = "hashing_error"; char *template_name = entry->template_desc->name; + struct ima_template_entry *duplicated_entry = NULL; int result;
if (!violation) { @@ -119,8 +121,26 @@ int ima_store_template(struct ima_template_entry *entry, return result; } } + + if (ima_plus_standard_pcr && !digest) { + duplicated_entry = kmemdup(entry, + sizeof(*entry) + entry->template_desc->num_fields * + sizeof(struct ima_field_data), GFP_KERNEL); + if (duplicated_entry) + duplicated_entry->pcr = ima_digest_list_pcr; + } else if (!ima_plus_standard_pcr && ima_digest_list_pcr >= 0) { + pcr = ima_digest_list_pcr; + } + entry->pcr = pcr; result = ima_add_template_entry(entry, violation, op, inode, filename); + if (!result && duplicated_entry) { + result = ima_add_template_entry(duplicated_entry, violation, op, + inode, filename); + if (result < 0) + kfree(duplicated_entry); + } + return result; }
@@ -152,8 +172,8 @@ void ima_add_violation(struct file *file, const unsigned char *filename, result = -ENOMEM; goto err_out; } - result = ima_store_template(entry, violation, inode, - filename, CONFIG_IMA_MEASURE_PCR_IDX); + result = ima_store_template(entry, violation, inode, filename, + CONFIG_IMA_MEASURE_PCR_IDX, NULL); if (result < 0) ima_free_template_entry(entry); err_out: @@ -341,13 +361,14 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, const unsigned char *filename, struct evm_ima_xattr_data *xattr_value, int xattr_len, const struct modsig *modsig, int pcr, - struct ima_template_desc *template_desc) + struct ima_template_desc *template_desc, + struct ima_digest *digest) { static const char op[] = "add_template_measure"; static const char audit_cause[] = "ENOMEM"; int result = -ENOMEM; struct inode *inode = file_inode(file); - struct ima_template_entry *entry; + struct ima_template_entry *entry = NULL; struct ima_event_data event_data = { .iint = iint, .file = file, .filename = filename, @@ -365,6 +386,11 @@ void ima_store_measurement(struct integrity_iint_cache *iint, if (iint->measured_pcrs & (0x1 << pcr) && !modsig) return;
+ if (digest && !ima_plus_standard_pcr && ima_digest_list_pcr >= 0) { + result = -EEXIST; + goto out; + } + result = ima_alloc_init_template(&event_data, &entry, template_desc); if (result < 0) { integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename, @@ -372,12 +398,14 @@ void ima_store_measurement(struct integrity_iint_cache *iint, return; }
- result = ima_store_template(entry, violation, inode, filename, pcr); + result = ima_store_template(entry, violation, inode, filename, pcr, + digest); +out: if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) { iint->flags |= IMA_MEASURED; iint->measured_pcrs |= (0x1 << pcr); } - if (result < 0) + if (result < 0 && entry) ima_free_template_entry(entry); }
diff --git a/security/integrity/ima/ima_digest_list.c b/security/integrity/ima/ima_digest_list.c index 91c70562aa86..42b2306e43cc 100644 --- a/security/integrity/ima/ima_digest_list.c +++ b/security/integrity/ima/ima_digest_list.c @@ -29,6 +29,31 @@ struct ima_h_table ima_digests_htable = { .queue[0 ... IMA_MEASURE_HTABLE_SIZE - 1] = HLIST_HEAD_INIT };
+static int __init digest_list_pcr_setup(char *str) +{ + int pcr, ret; + + ret = kstrtouint(str, 10, &pcr); + if (ret) { + pr_err("Invalid PCR number %s\n", str); + return 1; + } + + if (pcr == CONFIG_IMA_MEASURE_PCR_IDX) { + pr_err("Default PCR cannot be used for digest lists\n"); + return 1; + } + + ima_digest_list_pcr = pcr; + ima_digest_list_actions |= IMA_MEASURE; + + if (*str == '+') + ima_plus_standard_pcr = true; + + return 1; +} +__setup("ima_digest_list_pcr=", digest_list_pcr_setup); + /************************* * Get/add/del functions * *************************/ diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 63979aefc95f..be2aab51c220 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -85,7 +85,7 @@ static int __init ima_add_boot_aggregate(void)
result = ima_store_template(entry, violation, NULL, boot_aggregate_name, - CONFIG_IMA_MEASURE_PCR_IDX); + CONFIG_IMA_MEASURE_PCR_IDX, NULL); if (result < 0) { ima_free_template_entry(entry); audit_cause = "store_entry"; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index eac731e326f5..4d50c764af7f 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -28,6 +28,7 @@ #include <linux/fs.h>
#include "ima.h" +#include "ima_digest_list.h"
#ifdef CONFIG_IMA_APPRAISE int ima_appraise = IMA_APPRAISE_ENFORCE; @@ -39,6 +40,10 @@ int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1;
/* Actions (measure/appraisal) for which digest lists can be used */ int ima_digest_list_actions; +/* PCR used for digest list measurements */ +int ima_digest_list_pcr = -1; +/* Flag to include standard measurement if digest list PCR is specified */ +bool ima_plus_standard_pcr;
static int hash_setup_done;
@@ -180,6 +185,8 @@ static enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_v || sig->hash_algo >= HASH_ALGO__LAST) return ima_hash_algo; return sig->hash_algo; + case EVM_IMA_XATTR_DIGEST_LIST: + fallthrough; case IMA_XATTR_DIGEST_NG: /* first byte contains algorithm id */ ret = xattr_value->data[0]; @@ -273,6 +280,7 @@ static int process_measurement(struct file *file, const struct cred *cred, const char *pathname = NULL; int rc = 0, action, must_appraise = 0; int pcr = CONFIG_IMA_MEASURE_PCR_IDX; + struct ima_digest *found_digest; struct evm_ima_xattr_data *xattr_value = NULL; struct modsig *modsig = NULL; int xattr_len = 0; @@ -407,10 +415,16 @@ static int process_measurement(struct file *file, const struct cred *cred, if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ pathname = ima_d_path(&file->f_path, &pathbuf, filename);
+ found_digest = ima_lookup_digest(iint->ima_hash->digest, hash_algo, + COMPACT_FILE); + if (action & IMA_MEASURE) ima_store_measurement(iint, file, pathname, xattr_value, xattr_len, modsig, pcr, - template_desc); + template_desc, + ima_digest_allow(found_digest, + IMA_MEASURE)); + if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) { rc = ima_check_blacklist(iint, modsig, pcr); if (rc != -EPERM) { @@ -1060,7 +1074,7 @@ int process_buffer_measurement(struct mnt_idmap *idmap, goto out; }
- ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr); + ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr, NULL); if (ret < 0) { audit_cause = "store_entry"; ima_free_template_entry(entry); diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index cae4d1cebfd7..0c7f135bb556 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -1862,7 +1862,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) ima_log_string(ab, "pcr", args[0].from);
result = kstrtoint(args[0].from, 10, &entry->pcr); - if (result || INVALID_PCR(entry->pcr)) + if (result || INVALID_PCR(entry->pcr) || + entry->pcr == ima_digest_list_pcr) result = -EINVAL; else entry->flags |= IMA_PCR; diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 9b9c669634a9..538090a5f259 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -82,6 +82,7 @@ enum evm_ima_xattr_type { IMA_XATTR_DIGEST_NG, EVM_XATTR_PORTABLE_DIGSIG, IMA_VERITY_DIGSIG, + EVM_IMA_XATTR_DIGEST_LIST, IMA_XATTR_LAST };