[PATCH v6 14/17] ima: Tie opened SecurityFS files to the IMA namespace it belongs to
From: Stefan Berger
Date: Fri Dec 10 2021 - 14:48:10 EST
Tie IMA's files in SecurityFS to the IMA namespace they belong to so that
also file descriptor that were passed or inherited to other user/IMA
namespaces will always access the data of the IMA namespace they originally
belonged to.
Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
security/integrity/ima/ima_fs.c | 74 ++++++++++++++++++++++++-----
security/integrity/ima/ima_policy.c | 4 +-
2 files changed, 63 insertions(+), 15 deletions(-)
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 0e582ceecc7f..a136d14f29ec 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -35,6 +35,20 @@ static int __init default_canonical_fmt_setup(char *str)
}
__setup("ima_canonical_fmt", default_canonical_fmt_setup);
+static inline struct user_namespace *ima_user_ns_from_file(struct file *filp)
+{
+ return filp->f_path.mnt->mnt_sb->s_user_ns;
+}
+
+static int ima_open(struct inode *inode, struct file *file)
+{
+ struct user_namespace *user_ns = ima_user_ns_from_file(file);
+ struct ima_namespace *ns = user_ns->ima_ns;
+
+ file->private_data = ns;
+ return 0;
+}
+
static ssize_t ima_show_htable_value(char __user *buf, size_t count,
loff_t *ppos, atomic_long_t *val)
{
@@ -49,12 +63,13 @@ static ssize_t ima_show_htable_violations(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = filp->private_data;
return ima_show_htable_value(buf, count, ppos, &ns->ima_htable.violations);
}
static const struct file_operations ima_htable_violations_ops = {
+ .open = ima_open,
.read = ima_show_htable_violations,
.llseek = generic_file_llseek,
};
@@ -63,12 +78,13 @@ static ssize_t ima_show_measurements_count(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = filp->private_data;
return ima_show_htable_value(buf, count, ppos, &ns->ima_htable.len);
}
static const struct file_operations ima_measurements_count_ops = {
+ .open = ima_open,
.read = ima_show_measurements_count,
.llseek = generic_file_llseek,
};
@@ -76,7 +92,7 @@ static const struct file_operations ima_measurements_count_ops = {
/* returns pointer to hlist_node */
static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = m->private;
loff_t l = *pos;
struct ima_queue_entry *qe;
@@ -94,7 +110,7 @@ static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = m->private;
struct ima_queue_entry *qe = v;
/* lock protects when reading beyond last element
@@ -195,9 +211,26 @@ static const struct seq_operations ima_measurments_seqops = {
.show = ima_measurements_show
};
+static int ima_seq_open(struct file *file, const struct seq_operations *seq_ops)
+{
+ struct user_namespace *user_ns = ima_user_ns_from_file(file);
+ struct ima_namespace *ns = user_ns->ima_ns;
+ struct seq_file *seq;
+ int err;
+
+ err = seq_open(file, seq_ops);
+ if (err)
+ return err;
+
+ seq = file->private_data;
+ seq->private = ns;
+
+ return 0;
+}
+
static int ima_measurements_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &ima_measurments_seqops);
+ return ima_seq_open(file, &ima_measurments_seqops);
}
static const struct file_operations ima_measurements_ops = {
@@ -263,7 +296,7 @@ static const struct seq_operations ima_ascii_measurements_seqops = {
static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
{
- return seq_open(file, &ima_ascii_measurements_seqops);
+ return ima_seq_open(file, &ima_ascii_measurements_seqops);
}
static const struct file_operations ima_ascii_measurements_ops = {
@@ -273,9 +306,8 @@ static const struct file_operations ima_ascii_measurements_ops = {
.release = seq_release,
};
-static ssize_t ima_read_policy(char *path)
+static ssize_t ima_read_policy(struct ima_namespace *ns, char *path)
{
- struct ima_namespace *ns = get_current_ns();
void *data = NULL;
char *datap;
size_t size;
@@ -314,10 +346,23 @@ static ssize_t ima_read_policy(char *path)
return pathlen;
}
+static struct ima_namespace *ima_filp_private(struct file *filp)
+{
+ if (!(filp->f_flags & O_WRONLY)) {
+#ifdef CONFIG_IMA_READ_POLICY
+ struct seq_file *seq;
+
+ seq = filp->private_data;
+ return seq->private;
+#endif
+ }
+ return filp->private_data;
+}
+
static ssize_t ima_write_policy(struct file *file, const char __user *buf,
size_t datalen, loff_t *ppos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = ima_filp_private(file);
char *data;
ssize_t result;
@@ -340,7 +385,7 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
goto out_free;
if (data[0] == '/') {
- result = ima_read_policy(data);
+ result = ima_read_policy(ns, data);
} else if (ima_appraise & IMA_APPRAISE_POLICY) {
pr_err("signed policy file (specified as an absolute pathname) required\n");
integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
@@ -386,7 +431,8 @@ static const struct seq_operations ima_policy_seqops = {
*/
static int ima_open_policy(struct inode *inode, struct file *filp)
{
- struct ima_namespace *ns = get_current_ns();
+ struct user_namespace *user_ns = ima_user_ns_from_file(filp);
+ struct ima_namespace *ns = user_ns->ima_ns;
if (!(filp->f_flags & O_WRONLY)) {
#ifndef CONFIG_IMA_READ_POLICY
@@ -396,11 +442,13 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
return -EACCES;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- return seq_open(filp, &ima_policy_seqops);
+ return ima_seq_open(filp, &ima_policy_seqops);
#endif
}
if (test_and_set_bit(IMA_FS_BUSY, &ns->ima_fs_flags))
return -EBUSY;
+
+ filp->private_data = ns;
return 0;
}
@@ -413,7 +461,7 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
*/
static int ima_release_policy(struct inode *inode, struct file *file)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = ima_filp_private(file);
const char *cause = ns->valid_policy ? "completed" : "failed";
if ((file->f_flags & O_ACCMODE) == O_RDONLY)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 747dca6131d6..c2acd4cf529d 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1908,7 +1908,7 @@ static const char *const mask_tokens[] = {
void *ima_policy_start(struct seq_file *m, loff_t *pos)
{
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = m->private;
loff_t l = *pos;
struct ima_rule_entry *entry;
struct list_head *ima_rules_tmp;
@@ -1928,7 +1928,7 @@ void *ima_policy_start(struct seq_file *m, loff_t *pos)
void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ima_rule_entry *entry = v;
- struct ima_namespace *ns = get_current_ns();
+ struct ima_namespace *ns = m->private;
rcu_read_lock();
entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
--
2.31.1