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 <[email protected]>
---
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
On Fri, Dec 10, 2021 at 02:47:33PM -0500, Stefan Berger wrote:
> 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 <[email protected]>
> ---
> 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;
> +}
I'd probably rewrite this as:
static inline struct user_namespace *ima_user_ns_from_file(const struct file *filp)
{
return file_inode(filp)->i_sb->s_user_ns;
}
as it spares you some pointer chasing and also looks cleaner.
> +
> +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;
> +}
All of that isn't needed with my last proposal. You don't need to stash
anything anywhere. I showed that in my previous patch suggestion. The
original filp is stashed in the seq_file's private member, i.e. taking
ima_measurements_start(struct seq_file *m, loff_t *pos)
you can get at:
const struct file *filp = m->file;
struct user_namespace *user_ns = file_inode(filp)->i_sb->s_user_ns;
struct ima_namespace *ns = user_ns->ima_ns;
On 12/11/21 06:00, Christian Brauner wrote:
> On Fri, Dec 10, 2021 at 02:47:33PM -0500, Stefan Berger wrote:
>> 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 <[email protected]>
>> ---
>> 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;
>> +}
> I'd probably rewrite this as:
>
> static inline struct user_namespace *ima_user_ns_from_file(const struct file *filp)
> {
> return file_inode(filp)->i_sb->s_user_ns;
> }
>
> as it spares you some pointer chasing and also looks cleaner.
Ok. This patch is being absorbed by all the functions currently using
get_current_ns() and should access it via the file instead.
Stefan