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authorMimi Zohar <zohar@linux.vnet.ibm.com>2018-01-15 11:20:36 -0500
committerMimi Zohar <zohar@linux.vnet.ibm.com>2018-05-22 07:33:53 -0400
commitf1b08bbcbdaf3160fa95ec95a760a49adf312b67 (patch)
tree8eca8887dda0382e801a69102d6c2cce36616d61
parentfa516b66a1bfce1d72f1620c54bdfebc493000d1 (diff)
downloadlinux-stericsson-f1b08bbcbdaf3160fa95ec95a760a49adf312b67.tar.gz
ima: define a new policy condition based on the filesystem name
If/when file data signatures are distributed with the file data, this patch will not be needed. In the current environment where only some files are signed, the ability to differentiate between file systems is needed. Some file systems consider the file system magic number internal to the file system. This patch defines a new IMA policy condition named "fsname", based on the superblock's file_system_type (sb->s_type) name. This allows policy rules to be expressed in terms of the filesystem name. The following sample rules require file signatures on rootfs files executed or mmap'ed. appraise func=BPRM_CHECK fsname=rootfs appraise_type=imasig appraise func=FILE_MMAP fsname=rootfs appraise_type=imasig Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu>
-rw-r--r--Documentation/ABI/testing/ima_policy2
-rw-r--r--security/integrity/ima/ima_policy.c25
2 files changed, 25 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index b8465e00ba5f..74c6702de74e 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -21,7 +21,7 @@ Description:
audit | hash | dont_hash
condition:= base | lsm [option]
base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
- [euid=] [fowner=]]
+ [euid=] [fowner=] [fsname=]]
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [permit_directio]
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index d89bebf85421..03cbba423e59 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -33,6 +33,7 @@
#define IMA_INMASK 0x0040
#define IMA_EUID 0x0080
#define IMA_PCR 0x0100
+#define IMA_FSNAME 0x0200
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -74,6 +75,7 @@ struct ima_rule_entry {
void *args_p; /* audit value */
int type; /* audit type */
} lsm[MAX_LSM_RULES];
+ char *fsname;
};
/*
@@ -273,6 +275,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
if ((rule->flags & IMA_FSMAGIC)
&& rule->fsmagic != inode->i_sb->s_magic)
return false;
+ if ((rule->flags & IMA_FSNAME)
+ && strcmp(rule->fsname, inode->i_sb->s_type->name))
+ return false;
if ((rule->flags & IMA_FSUUID) &&
!uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
return false;
@@ -540,7 +545,7 @@ enum {
Opt_audit, Opt_hash, Opt_dont_hash,
Opt_obj_user, Opt_obj_role, Opt_obj_type,
Opt_subj_user, Opt_subj_role, Opt_subj_type,
- Opt_func, Opt_mask, Opt_fsmagic,
+ Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
@@ -565,6 +570,7 @@ static match_table_t policy_tokens = {
{Opt_func, "func=%s"},
{Opt_mask, "mask=%s"},
{Opt_fsmagic, "fsmagic=%s"},
+ {Opt_fsname, "fsname=%s"},
{Opt_fsuuid, "fsuuid=%s"},
{Opt_uid_eq, "uid=%s"},
{Opt_euid_eq, "euid=%s"},
@@ -776,6 +782,17 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
if (!result)
entry->flags |= IMA_FSMAGIC;
break;
+ case Opt_fsname:
+ ima_log_string(ab, "fsname", args[0].from);
+
+ entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
+ if (!entry->fsname) {
+ result = -ENOMEM;
+ break;
+ }
+ result = 0;
+ entry->flags |= IMA_FSNAME;
+ break;
case Opt_fsuuid:
ima_log_string(ab, "fsuuid", args[0].from);
@@ -1104,6 +1121,12 @@ int ima_policy_show(struct seq_file *m, void *v)
seq_puts(m, " ");
}
+ if (entry->flags & IMA_FSNAME) {
+ snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
+ seq_printf(m, pt(Opt_fsname), tbuf);
+ seq_puts(m, " ");
+ }
+
if (entry->flags & IMA_PCR) {
snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
seq_printf(m, pt(Opt_pcr), tbuf);