From 6ccd045630054c99ba1bb35673db12cfcf1eea58 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 20 Apr 2010 10:20:54 -0400 Subject: ima: handle multiple rules per write Currently IMA will only accept one rule per write(). This patch allows IMA to accept writes which contain multiple rules but only processes one rule per write. \n is used as the delimiter between rules. IMA will return a short write indicating that it only accepted up to the first \n. This allows simple userspace utilities like cat to be used to load an IMA policy instead of needing a special userspace utility that understood 'one write per rule' Signed-off-by: Eric Paris Acked-by: Mimi Zohar Signed-off-by: James Morris --- security/integrity/ima/ima.h | 2 +- security/integrity/ima/ima_fs.c | 38 +++++++++++++++++++------------------ security/integrity/ima/ima_policy.c | 18 +++++++++++------- 3 files changed, 32 insertions(+), 26 deletions(-) (limited to 'security') diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 47fb65d1fcb..16d100d3fc3 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -135,7 +135,7 @@ enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK }; int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask); void ima_init_policy(void); void ima_update_policy(void); -int ima_parse_add_rule(char *); +ssize_t ima_parse_add_rule(char *); void ima_delete_rules(void); /* LSM based policy rules require audit */ diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 0c72c9c3895..3674a52e1cf 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -243,32 +243,34 @@ static const struct file_operations ima_ascii_measurements_ops = { static ssize_t ima_write_policy(struct file *file, const char __user *buf, size_t datalen, loff_t *ppos) { - char *data; - int rc; + char *data = NULL; + ssize_t result; if (datalen >= PAGE_SIZE) - return -ENOMEM; - if (*ppos != 0) { - /* No partial writes. */ - return -EINVAL; - } + datalen = PAGE_SIZE - 1; + + /* No partial writes. */ + result = -EINVAL; + if (*ppos != 0) + goto out; + + result = -ENOMEM; data = kmalloc(datalen + 1, GFP_KERNEL); if (!data) - return -ENOMEM; + goto out; - if (copy_from_user(data, buf, datalen)) { - kfree(data); - return -EFAULT; - } *(data + datalen) = '\0'; - rc = ima_parse_add_rule(data); - if (rc < 0) { - datalen = -EINVAL; - valid_policy = 0; - } + result = -EFAULT; + if (copy_from_user(data, buf, datalen)) + goto out; + + result = ima_parse_add_rule(data); +out: + if (result < 0) + valid_policy = 0; kfree(data); - return datalen; + return result; } static struct dentry *ima_dir; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 4759d0f9933..49998f90e44 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -261,7 +261,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); entry->action = -1; - while ((p = strsep(&rule, " \n")) != NULL) { + while ((p = strsep(&rule, " ")) != NULL) { substring_t args[MAX_OPT_ARGS]; int token; unsigned long lnum; @@ -269,7 +269,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) if (result < 0) break; if (!*p) - continue; + break; token = match_token(p, policy_tokens, args); switch (token) { case Opt_measure: @@ -373,7 +373,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) if (entry->action == UNKNOWN) result = -EINVAL; - audit_log_format(ab, "res=%d", !result ? 0 : 1); + audit_log_format(ab, "res=%d", !!result); audit_log_end(ab); return result; } @@ -383,13 +383,14 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) * @rule - ima measurement policy rule * * Uses a mutex to protect the policy list from multiple concurrent writers. - * Returns 0 on success, an error code on failure. + * Returns the length of the rule parsed, an error code on failure */ -int ima_parse_add_rule(char *rule) +ssize_t ima_parse_add_rule(char *rule) { const char *op = "update_policy"; + char *p; struct ima_measure_rule_entry *entry; - int result = 0; + ssize_t result, len; int audit_info = 0; /* Prevent installed policy from changing */ @@ -409,8 +410,11 @@ int ima_parse_add_rule(char *rule) INIT_LIST_HEAD(&entry->list); - result = ima_parse_rule(rule, entry); + p = strsep(&rule, "\n"); + len = strlen(p) + 1; + result = ima_parse_rule(p, entry); if (!result) { + result = len; mutex_lock(&ima_measure_mutex); list_add_tail(&entry->list, &measure_policy_rules); mutex_unlock(&ima_measure_mutex); -- cgit v1.2.3-18-g5258