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ima: add support for new "euid" policy condition

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The new "euid" policy condition measures files with the specified
effective uid (euid).  In addition, for CAP_SETUID files it measures
files with the specified uid or suid.

Changelog:
- fixed checkpatch.pl warnings
- fixed avc denied {setuid} messages - based on Roberto's feedback

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dr. Greg Wettstein <gw@idfusion.org>
Cc: stable@vger.kernel.org
This commit is contained in:
Mimi Zohar 2014-11-05 07:48:36 -05:00
parent 45b26133b9
commit 139069eff7
2 changed files with 25 additions and 5 deletions
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3
Documentation/ABI/testing/ima_policy
View File

@ -20,7 +20,7 @@ Description:
action: measure | dont_measure | appraise | dont_appraise | audit
condition:= base | lsm [option]
base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
[fowner]]
[euid=] [fowner=]]
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [permit_directio]
@ -31,6 +31,7 @@ Description:
fsmagic:= hex value
fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
uid:= decimal value
euid:= decimal value
fowner:=decimal value
lsm: are LSM specific
option: appraise_type:= [imasig]

27
security/integrity/ima/ima_policy.c
View File

@ -27,6 +27,7 @@
#define IMA_UID 0x0008
#define IMA_FOWNER 0x0010
#define IMA_FSUUID 0x0020
#define IMA_EUID 0x0080
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@ -194,6 +195,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
return false;
if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
return false;
if (rule->flags & IMA_EUID) {
if (has_capability_noaudit(current, CAP_SETUID)) {
if (!uid_eq(rule->uid, cred->euid)
&& !uid_eq(rule->uid, cred->suid)
&& !uid_eq(rule->uid, cred->uid))
return false;
} else if (!uid_eq(rule->uid, cred->euid))
return false;
}
if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
@ -373,7 +384,8 @@ enum {
Opt_audit,
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_uid, Opt_fowner,
Opt_func, Opt_mask, Opt_fsmagic,
Opt_uid, Opt_euid, Opt_fowner,
Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
};
@ -394,6 +406,7 @@ static match_table_t policy_tokens = {
{Opt_fsmagic, "fsmagic=%s"},
{Opt_fsuuid, "fsuuid=%s"},
{Opt_uid, "uid=%s"},
{Opt_euid, "euid=%s"},
{Opt_fowner, "fowner=%s"},
{Opt_appraise_type, "appraise_type=%s"},
{Opt_permit_directio, "permit_directio"},
@ -566,6 +579,9 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
break;
case Opt_uid:
ima_log_string(ab, "uid", args[0].from);
case Opt_euid:
if (token == Opt_euid)
ima_log_string(ab, "euid", args[0].from);
if (uid_valid(entry->uid)) {
result = -EINVAL;
@ -574,11 +590,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
result = kstrtoul(args[0].from, 10, &lnum);
if (!result) {
entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
entry->uid = make_kuid(current_user_ns(),
(uid_t) lnum);
if (!uid_valid(entry->uid) ||
(uid_t)lnum != lnum)
result = -EINVAL;
else
entry->flags |= IMA_UID;
entry->flags |= (token == Opt_uid)
? IMA_UID : IMA_EUID;
}
break;
case Opt_fowner: