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James Morris committed Jun 18, 2015
2 parents 49afd72 + 24fd03c commit b3bddff
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Showing 6 changed files with 112 additions and 25 deletions.
6 changes: 4 additions & 2 deletions Documentation/ABI/testing/ima_policy
Original file line number Diff line number Diff line change
Expand Up @@ -20,17 +20,19 @@ 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]

base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
[[^]MAY_EXEC]
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]
Expand Down
10 changes: 9 additions & 1 deletion Documentation/kernel-parameters.txt
Original file line number Diff line number Diff line change
Expand Up @@ -1398,7 +1398,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
The list of supported hash algorithms is defined
in crypto/hash_info.h.

ima_tcb [IMA]
ima_policy= [IMA]
The builtin measurement policy to load during IMA
setup. Specyfing "tcb" as the value, measures all
programs exec'd, files mmap'd for exec, and all files
opened with the read mode bit set by either the
effective uid (euid=0) or uid=0.
Format: "tcb"

ima_tcb [IMA] Deprecated. Use ima_policy= instead.
Load a policy which meets the needs of the Trusted
Computing Base. This means IMA will measure all
programs exec'd, files mmap'd for exec, and all files
Expand Down
2 changes: 1 addition & 1 deletion security/integrity/ima/ima.h
Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
const char *op, const char *cause);
int ima_init_crypto(void);
void ima_putc(struct seq_file *m, void *data, int datalen);
void ima_print_digest(struct seq_file *m, u8 *digest, int size);
void ima_print_digest(struct seq_file *m, u8 *digest, u32 size);
struct ima_template_desc *ima_template_desc_current(void);
int ima_init_template(void);

Expand Down
4 changes: 2 additions & 2 deletions security/integrity/ima/ima_fs.c
Original file line number Diff line number Diff line change
Expand Up @@ -190,9 +190,9 @@ static const struct file_operations ima_measurements_ops = {
.release = seq_release,
};

void ima_print_digest(struct seq_file *m, u8 *digest, int size)
void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
{
int i;
u32 i;

for (i = 0; i < size; i++)
seq_printf(m, "%02x", *(digest + i));
Expand Down
112 changes: 94 additions & 18 deletions security/integrity/ima/ima_policy.c
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,8 @@
#define IMA_UID 0x0008
#define IMA_FOWNER 0x0010
#define IMA_FSUUID 0x0020
#define IMA_INMASK 0x0040
#define IMA_EUID 0x0080

#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
Expand All @@ -42,6 +44,8 @@ enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
};

enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };

struct ima_rule_entry {
struct list_head list;
int action;
Expand Down Expand Up @@ -70,7 +74,7 @@ struct ima_rule_entry {
* normal users can easily run the machine out of memory simply building
* and running executables.
*/
static struct ima_rule_entry default_rules[] = {
static struct ima_rule_entry dont_measure_rules[] = {
{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
Expand All @@ -81,13 +85,29 @@ static struct ima_rule_entry default_rules[] = {
{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
.flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}
};

static struct ima_rule_entry original_measurement_rules[] = {
{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
.flags = IMA_FUNC | IMA_MASK},
{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
.flags = IMA_FUNC | IMA_MASK},
{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID,
.flags = IMA_FUNC | IMA_MASK | IMA_UID},
{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
.uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_MASK | IMA_UID},
{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
};

static struct ima_rule_entry default_measurement_rules[] = {
{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
.flags = IMA_FUNC | IMA_MASK},
{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
.flags = IMA_FUNC | IMA_MASK},
{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
.uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
.uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
};
Expand Down Expand Up @@ -119,14 +139,29 @@ static struct list_head *ima_rules;

static DEFINE_MUTEX(ima_rules_mutex);

static bool ima_use_tcb __initdata;
static int ima_policy __initdata;
static int __init default_measure_policy_setup(char *str)
{
ima_use_tcb = 1;
if (ima_policy)
return 1;

ima_policy = ORIGINAL_TCB;
return 1;
}
__setup("ima_tcb", default_measure_policy_setup);

static int __init policy_setup(char *str)
{
if (ima_policy)
return 1;

if (strcmp(str, "tcb") == 0)
ima_policy = DEFAULT_TCB;

return 1;
}
__setup("ima_policy=", policy_setup);

static bool ima_use_appraise_tcb __initdata;
static int __init default_appraise_policy_setup(char *str)
{
Expand Down Expand Up @@ -186,6 +221,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
if ((rule->flags & IMA_MASK) &&
(rule->mask != mask && func != POST_SETATTR))
return false;
if ((rule->flags & IMA_INMASK) &&
(!(rule->mask & mask) && func != POST_SETATTR))
return false;
if ((rule->flags & IMA_FSMAGIC)
&& rule->fsmagic != inode->i_sb->s_magic)
return false;
Expand All @@ -194,6 +232,16 @@ 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++) {
Expand Down Expand Up @@ -337,13 +385,27 @@ void __init ima_init_policy(void)
{
int i, measure_entries, appraise_entries;

/* if !ima_use_tcb set entries = 0 so we load NO default rules */
measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
/* if !ima_policy set entries = 0 so we load NO default rules */
measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0;
appraise_entries = ima_use_appraise_tcb ?
ARRAY_SIZE(default_appraise_rules) : 0;

for (i = 0; i < measure_entries; i++)
list_add_tail(&default_rules[i].list, &ima_default_rules);
list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);

switch (ima_policy) {
case ORIGINAL_TCB:
for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++)
list_add_tail(&original_measurement_rules[i].list,
&ima_default_rules);
break;
case DEFAULT_TCB:
for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++)
list_add_tail(&default_measurement_rules[i].list,
&ima_default_rules);
default:
break;
}

for (i = 0; i < appraise_entries; i++) {
list_add_tail(&default_appraise_rules[i].list,
Expand Down Expand Up @@ -373,7 +435,8 @@ 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
};

Expand All @@ -394,6 +457,7 @@ 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"},
Expand Down Expand Up @@ -435,6 +499,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
struct audit_buffer *ab;
char *from;
char *p;
int result = 0;

Expand Down Expand Up @@ -525,18 +590,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
if (entry->mask)
result = -EINVAL;

if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
from = args[0].from;
if (*from == '^')
from++;

if ((strcmp(from, "MAY_EXEC")) == 0)
entry->mask = MAY_EXEC;
else if (strcmp(args[0].from, "MAY_WRITE") == 0)
else if (strcmp(from, "MAY_WRITE") == 0)
entry->mask = MAY_WRITE;
else if (strcmp(args[0].from, "MAY_READ") == 0)
else if (strcmp(from, "MAY_READ") == 0)
entry->mask = MAY_READ;
else if (strcmp(args[0].from, "MAY_APPEND") == 0)
else if (strcmp(from, "MAY_APPEND") == 0)
entry->mask = MAY_APPEND;
else
result = -EINVAL;
if (!result)
entry->flags |= IMA_MASK;
entry->flags |= (*args[0].from == '^')
? IMA_INMASK : IMA_MASK;
break;
case Opt_fsmagic:
ima_log_string(ab, "fsmagic", args[0].from);
Expand Down Expand Up @@ -566,6 +636,9 @@ 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;
Expand All @@ -574,11 +647,14 @@ 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:
Expand Down
3 changes: 2 additions & 1 deletion security/integrity/ima/ima_template_lib.c
Original file line number Diff line number Diff line change
Expand Up @@ -70,7 +70,8 @@ static void ima_show_template_data_ascii(struct seq_file *m,
enum data_formats datafmt,
struct ima_field_data *field_data)
{
u8 *buf_ptr = field_data->data, buflen = field_data->len;
u8 *buf_ptr = field_data->data;
u32 buflen = field_data->len;

switch (datafmt) {
case DATA_FMT_DIGEST_WITH_ALGO:
Expand Down

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