From: Roberto Sassu <[email protected]>
Change ima_post_path_mknod() definition, so that it can be registered as
implementation of the path_post_mknod hook.
Also, make sure that ima_post_path_mknod() is executed only if
(mode & S_IFMT) is equal to zero or S_IFREG.
Add this check to take into account the different placement of the
path_post_mknod hook (to be introduced) in do_mknodat(). Since the new hook
will be placed after the switch(), the check ensures that
ima_post_path_mknod() is invoked as originally intended when it is
registered as implementation of path_post_mknod.
Signed-off-by: Roberto Sassu <[email protected]>
---
fs/namei.c | 3 ++-
include/linux/ima.h | 7 +++++--
security/integrity/ima/ima_main.c | 10 +++++++++-
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index edfedfbccae..b5a1ec29193 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3966,7 +3966,8 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
error = vfs_create(idmap, path.dentry->d_inode,
dentry, mode, true);
if (!error)
- ima_post_path_mknod(idmap, dentry);
+ ima_post_path_mknod(idmap, &path, dentry, mode,
+ dev);
break;
case S_IFCHR: case S_IFBLK:
error = vfs_mknod(idmap, path.dentry->d_inode,
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 910a2f11a90..179ce52013b 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -32,7 +32,8 @@ extern int ima_read_file(struct file *file, enum kernel_read_file_id id,
extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
enum kernel_read_file_id id);
extern void ima_post_path_mknod(struct mnt_idmap *idmap,
- struct dentry *dentry);
+ const struct path *dir, struct dentry *dentry,
+ umode_t mode, unsigned int dev);
extern int ima_file_hash(struct file *file, char *buf, size_t buf_size);
extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size);
extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size);
@@ -114,7 +115,9 @@ static inline int ima_post_read_file(struct file *file, void *buf, loff_t size,
}
static inline void ima_post_path_mknod(struct mnt_idmap *idmap,
- struct dentry *dentry)
+ const struct path *dir,
+ struct dentry *dentry,
+ umode_t mode, unsigned int dev)
{
return;
}
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index d66a0a36415..8941305376b 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -692,18 +692,26 @@ void ima_post_create_tmpfile(struct mnt_idmap *idmap,
/**
* ima_post_path_mknod - mark as a new inode
* @idmap: idmap of the mount the inode was found from
+ * @dir: path structure of parent of the new file
* @dentry: newly created dentry
+ * @mode: mode of the new file
+ * @dev: undecoded device number
*
* Mark files created via the mknodat syscall as new, so that the
* file data can be written later.
*/
void ima_post_path_mknod(struct mnt_idmap *idmap,
- struct dentry *dentry)
+ const struct path *dir, struct dentry *dentry,
+ umode_t mode, unsigned int dev)
{
struct integrity_iint_cache *iint;
struct inode *inode = dentry->d_inode;
int must_appraise;
+ /* See do_mknodat(), IMA is executed for case 0: and case S_IFREG: */
+ if ((mode & S_IFMT) != 0 && (mode & S_IFMT) != S_IFREG)
+ return;
+
if (!ima_policy_flag || !S_ISREG(inode->i_mode))
return;
--
2.25.1
On 3/3/23 13:18, Roberto Sassu wrote:
> From: Roberto Sassu <[email protected]>
>
> Change ima_post_path_mknod() definition, so that it can be registered as
> implementation of the path_post_mknod hook.
>
> Also, make sure that ima_post_path_mknod() is executed only if
> (mode & S_IFMT) is equal to zero or S_IFREG.
>
> Add this check to take into account the different placement of the
> path_post_mknod hook (to be introduced) in do_mknodat(). Since the new hook
> will be placed after the switch(), the check ensures that
> ima_post_path_mknod() is invoked as originally intended when it is
> registered as implementation of path_post_mknod.
case 0: case S_IFREG: <---- this here
error = vfs_create(mnt_userns, path.dentry->d_inode,
dentry, mode, true);
if (!error)
ima_post_path_mknod(mnt_userns, dentry);
>
> Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>