[PATCH v15 09/23] LSM: Use lsmblob in security_task_getsecid

Casey Schaufler
2020-02-22T00:05:16Z

Change the security_task_getsecid() interface to fill in
a lsmblob structure instead of a u32 secid in support of
LSM stacking. Audit interfaces will need to collect all
possible secids for possible reporting.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: linux-integrity@vger.kernel.org
---
drivers/android/binder.c | 4 +--
include/linux/security.h | 7 +++--
kernel/audit.c | 11 +++----
kernel/auditfilter.c | 4 +--
kernel/auditsc.c | 18 ++++++++----
net/netlabel/netlabel_unlabeled.c | 5 +++-
net/netlabel/netlabel_user.h | 6 +++-
security/integrity/ima/ima_appraise.c | 10 ++++---
security/integrity/ima/ima_main.c | 42 +++++++++++++++------------
security/security.c | 12 ++++++--
10 files changed, 72 insertions(+), 47 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a9d9b69d5596..b133f0af5151 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3106,12 +3106,10 @@ static void binder_transaction(struct binder_proc *proc,
t->priority = task_nice(current);

if (target_node && target_node->txn_security_ctx) {
- u32 secid;
struct lsmblob blob;
size_t added_size;

- security_task_getsecid(proc->tsk, &secid);
- lsmblob_init(&blob, secid);
+ security_task_getsecid(proc->tsk, &blob);
ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
if (ret) {
return_error = BR_FAILED_REPLY;
diff --git a/include/linux/security.h b/include/linux/security.h
index 3ceea6c51bed..b5ffb2286bcf 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -451,7 +451,7 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
int security_task_setpgid(struct task_struct *p, pid_t pgid);
int security_task_getpgid(struct task_struct *p);
int security_task_getsid(struct task_struct *p);
-void security_task_getsecid(struct task_struct *p, u32 *secid);
+void security_task_getsecid(struct task_struct *p, struct lsmblob *blob);
int security_task_setnice(struct task_struct *p, int nice);
int security_task_setioprio(struct task_struct *p, int ioprio);
int security_task_getioprio(struct task_struct *p);
@@ -1103,9 +1103,10 @@ static inline int security_task_getsid(struct task_struct *p)
return 0;
}

-static inline void security_task_getsecid(struct task_struct *p, u32 *secid)
+static inline void security_task_getsecid(struct task_struct *p,
+ struct lsmblob *blob)
{
- *secid = 0;
+ lsmblob_init(blob, 0);
}

static inline int security_task_setnice(struct task_struct *p, int nice)
diff --git a/kernel/audit.c b/kernel/audit.c
index 0fdd51d03598..d7d51ad5d234 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2063,14 +2063,12 @@ int audit_log_task_context(struct audit_buffer *ab)
char *ctx = NULL;
unsigned len;
int error;
- u32 sid;
struct lsmblob blob;

- security_task_getsecid(current, &sid);
- if (!sid)
+ security_task_getsecid(current, &blob);
+ if (!lsmblob_is_set(&blob))
return 0;

- lsmblob_init(&blob, sid);
error = security_secid_to_secctx(&blob, &ctx, &len);
if (error) {
if (error != -EINVAL)
@@ -2278,6 +2276,7 @@ int audit_set_loginuid(kuid_t loginuid)
int audit_signal_info(int sig, struct task_struct *t)
{
kuid_t uid = current_uid(), auid;
+ struct lsmblob blob;

if (auditd_test_task(t) &&
(sig == SIGTERM || sig == SIGHUP ||
@@ -2288,7 +2287,9 @@ int audit_signal_info(int sig, struct task_struct *t)
audit_sig_uid = auid;
else
audit_sig_uid = uid;
- security_task_getsecid(current, &audit_sig_sid);
+ security_task_getsecid(current, &blob);
+ /* scaffolding until audit_sig_sid is converted */
+ audit_sig_sid = blob.secid[0];
}

return audit_signal_info_syscall(t);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 509eb21eff7f..c9a46b78b932 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1326,7 +1326,6 @@ int audit_filter(int msgtype, unsigned int listtype)
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
pid_t pid;
- u32 sid;
struct lsmblob blob;

switch (f->type) {
@@ -1357,8 +1356,7 @@ int audit_filter(int msgtype, unsigned int listtype)
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
if (f->lsm_isset) {
- security_task_getsecid(current, &sid);
- lsmblob_init(&blob, sid);
+ security_task_getsecid(current, &blob);
result = security_audit_rule_match(
&blob, f->type, f->op,
f->lsm_rules);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 032cdb603ac0..3e5ccb7a46d1 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -444,7 +444,6 @@ static int audit_filter_rules(struct task_struct *tsk,
{
const struct cred *cred;
int i, need_sid = 1;
- u32 sid;
struct lsmblob blob;
unsigned int sessionid;

@@ -641,10 +640,9 @@ static int audit_filter_rules(struct task_struct *tsk,
logged upon error */
if (f->lsm_isset) {
if (need_sid) {
- security_task_getsecid(tsk, &sid);
+ security_task_getsecid(tsk, &blob);
need_sid = 0;
}
- lsmblob_init(&blob, sid);
result = security_audit_rule_match(&blob,
f->type,
f->op,
@@ -2382,12 +2380,15 @@ int __audit_sockaddr(int len, void *a)
void __audit_ptrace(struct task_struct *t)
{
struct audit_context *context = audit_context();
+ struct lsmblob blob;

context->target_pid = task_tgid_nr(t);
context->target_auid = audit_get_loginuid(t);
context->target_uid = task_uid(t);
context->target_sessionid = audit_get_sessionid(t);
- security_task_getsecid(t, &context->target_sid);
+ security_task_getsecid(t, &blob);
+ /* scaffolding - until target_sid is converted */
+ context->target_sid = blob.secid[0];
memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
}

@@ -2403,6 +2404,7 @@ int audit_signal_info_syscall(struct task_struct *t)
struct audit_aux_data_pids *axp;
struct audit_context *ctx = audit_context();
kuid_t t_uid = task_uid(t);
+ struct lsmblob blob;

if (!audit_signals || audit_dummy_context())
return 0;
@@ -2414,7 +2416,9 @@ int audit_signal_info_syscall(struct task_struct *t)
ctx->target_auid = audit_get_loginuid(t);
ctx->target_uid = t_uid;
ctx->target_sessionid = audit_get_sessionid(t);
- security_task_getsecid(t, &ctx->target_sid);
+ security_task_getsecid(t, &blob);
+ /* scaffolding until target_sid is converted */
+ ctx->target_sid = blob.secid[0];
memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
return 0;
}
@@ -2435,7 +2439,9 @@ int audit_signal_info_syscall(struct task_struct *t)
axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
axp->target_uid[axp->pid_count] = t_uid;
axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
- security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
+ security_task_getsecid(t, &blob);
+ /* scaffolding until target_sid is converted */
+ axp->target_sid[axp->pid_count] = blob.secid[0];
memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
axp->pid_count++;

diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index 0cda17cb44a0..e279b81d9545 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -1539,11 +1539,14 @@ int __init netlbl_unlabel_defconf(void)
int ret_val;
struct netlbl_dom_map *entry;
struct netlbl_audit audit_info;
+ struct lsmblob blob;

/* Only the kernel is allowed to call this function and the only time
* it is called is at bootup before the audit subsystem is reporting
* messages so don't worry to much about these values. */
- security_task_getsecid(current, &audit_info.secid);
+ security_task_getsecid(current, &blob);
+ /* scaffolding until audit_info.secid is converted */
+ audit_info.secid = blob.secid[0];
audit_info.loginuid = GLOBAL_ROOT_UID;
audit_info.sessionid = 0;

diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
index 3c67afce64f1..438b5db6c714 100644
--- a/net/netlabel/netlabel_user.h
+++ b/net/netlabel/netlabel_user.h
@@ -34,7 +34,11 @@
static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
struct netlbl_audit *audit_info)
{
- security_task_getsecid(current, &audit_info->secid);
+ struct lsmblob blob;
+
+ security_task_getsecid(current, &blob);
+ /* scaffolding until secid is converted */
+ audit_info->secid = blob.secid[0];
audit_info->loginuid = audit_get_loginuid(current);
audit_info->sessionid = audit_get_sessionid(current);
}
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index a9649b04b9f1..3dfb573c7171 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -48,14 +48,16 @@ bool is_ima_appraise_enabled(void)
*/
int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
{
- u32 secid;
+ struct lsmblob blob;

if (!ima_appraise)
return 0;

- security_task_getsecid(current, &secid);
- return ima_match_policy(inode, current_cred(), secid, func, mask,
- IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
+ security_task_getsecid(current, &blob);
+ /* scaffolding the .secid[0] */
+ return ima_match_policy(inode, current_cred(), blob.secid[0], func,
+ mask, IMA_APPRAISE | IMA_HASH, NULL, NULL,
+ NULL);
}

static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9fe949c6a530..1f50f68a6f5b 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -384,12 +384,13 @@ static int process_measurement(struct file *file, const struct cred *cred,
*/
int ima_file_mmap(struct file *file, unsigned long prot)
{
- u32 secid;
+ struct lsmblob blob;

if (file && (prot & PROT_EXEC)) {
- security_task_getsecid(current, &secid);
- return process_measurement(file, current_cred(), secid, NULL,
- 0, MAY_EXEC, MMAP_CHECK);
+ security_task_getsecid(current, &blob);
+ /* scaffolding - until process_measurement changes */
+ return process_measurement(file, current_cred(), blob.secid[0],
+ NULL, 0, MAY_EXEC, MMAP_CHECK);
}

return 0;
@@ -412,10 +413,12 @@ int ima_bprm_check(struct linux_binprm *bprm)
{
int ret;
u32 secid;
+ struct lsmblob blob;

- security_task_getsecid(current, &secid);
- ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
- MAY_EXEC, BPRM_CHECK);
+ security_task_getsecid(current, &blob);
+ /* scaffolding until process_measurement changes */
+ ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
+ NULL, 0, MAY_EXEC, BPRM_CHECK);
if (ret)
return ret;

@@ -436,10 +439,11 @@ int ima_bprm_check(struct linux_binprm *bprm)
*/
int ima_file_check(struct file *file, int mask)
{
- u32 secid;
+ struct lsmblob blob;

- security_task_getsecid(current, &secid);
- return process_measurement(file, current_cred(), secid, NULL, 0,
+ security_task_getsecid(current, &blob);
+ /* scaffolding until process_measurement changes */
+ return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
MAY_APPEND), FILE_CHECK);
}
@@ -597,7 +601,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
enum kernel_read_file_id read_id)
{
enum ima_hooks func;
- u32 secid;
+ struct lsmblob blob;

if (!file && read_id == READING_FIRMWARE) {
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
@@ -619,9 +623,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
}

func = read_idmap[read_id] ?: FILE_CHECK;
- security_task_getsecid(current, &secid);
- return process_measurement(file, current_cred(), secid, buf, size,
- MAY_READ, func);
+ security_task_getsecid(current, &blob);
+ /* scaffolding until process_measurement changes */
+ return process_measurement(file, current_cred(), blob.secid[0], buf,
+ size, MAY_READ, func);
}

/**
@@ -703,7 +708,7 @@ void process_buffer_measurement(const void *buf, int size,
} hash = {};
int violation = 0;
int action = 0;
- u32 secid;
+ struct lsmblob blob;

if (!ima_policy_flag)
return;
@@ -716,9 +721,10 @@ void process_buffer_measurement(const void *buf, int size,
* buffer measurements.
*/
if (func) {
- security_task_getsecid(current, &secid);
- action = ima_get_action(NULL, current_cred(), secid, 0, func,
- &pcr, &template, keyring);
+ security_task_getsecid(current, &blob);
+ /* scaffolding */
+ action = ima_get_action(NULL, current_cred(), blob.secid[0], 0,
+ func, &pcr, &template, keyring);
if (!(action & IMA_MEASURE))
return;
}
diff --git a/security/security.c b/security/security.c
index 9d67db68f6f2..85cdd24abcd6 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1732,10 +1732,16 @@ int security_task_getsid(struct task_struct *p)
return call_int_hook(task_getsid, 0, p);
}

-void security_task_getsecid(struct task_struct *p, u32 *secid)
+void security_task_getsecid(struct task_struct *p, struct lsmblob *blob)
{
- *secid = 0;
- call_void_hook(task_getsecid, p, secid);
+ struct security_hook_list *hp;
+
+ lsmblob_init(blob, 0);
+ hlist_for_each_entry(hp, &security_hook_heads.task_getsecid, list) {
+ if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+ continue;
+ hp->hook.task_getsecid(p, &blob->secid[hp->lsmid->slot]);
+ }
}
EXPORT_SYMBOL(security_task_getsecid);

--
2.24.1