On Fri, Feb 13, 2026 at 12:49:47PM -0500, Mimi Zohar wrote:
> Commit db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get the i_version")
> replaced detecting file change based on i_version with
> STATX_CHANGE_COOKIE.
>
> On filesystems without STATX_CHANGE_COOKIE enabled, revert back to
> detecting file change based on i_version.
>
> On filesystems which do not support either, assume the file changed.
>
Tested-by: Frederick Lawler <[email protected]>
> Reported-by: Roberto Sassu <[email protected]>
> Fixes: db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get the i_version")
> Signed-off-by: Mimi Zohar <[email protected]>
> ---
> Changelog v2:
> - Use the real_inode's iversion to detect file change on overlayfs
> - Add Roberto's Reported-by tag
>
> security/integrity/ima/ima_api.c | 13 +++++++----
> security/integrity/ima/ima_main.c | 39 ++++++++++++++++++++++++-------
> 2 files changed, 40 insertions(+), 12 deletions(-)
>
> diff --git a/security/integrity/ima/ima_api.c
> b/security/integrity/ima/ima_api.c
> index c35ea613c9f8..28cf1fe07f8f 100644
> --- a/security/integrity/ima/ima_api.c
> +++ b/security/integrity/ima/ima_api.c
> @@ -267,15 +267,20 @@ int ima_collect_measurement(struct ima_iint_cache
> *iint, struct file *file,
> goto out;
>
> /*
> - * Detecting file change is based on i_version. On filesystems
> - * which do not support i_version, support was originally limited
> - * to an initial measurement/appraisal/audit, but was modified to
> - * assume the file changed.
> + * Detect file change based on STATX_CHANGE_COOKIE, when supported,
> + * and fallback to detecting file change based on i_version.
> + *
> + * On filesystems which did not support i_version, support was
> + * originally limited to an initial measurement/appraisal/audit,
> + * but was later modified to assume the file changed.
> */
> result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE,
> AT_STATX_SYNC_AS_STAT);
> if (!result && (stat.result_mask & STATX_CHANGE_COOKIE))
> i_version = stat.change_cookie;
> + else if (IS_I_VERSION(real_inode))
> + i_version = inode_peek_iversion(real_inode);
> +
> hash.hdr.algo = algo;
> hash.hdr.length = hash_digest_size[algo];
>
> diff --git a/security/integrity/ima/ima_main.c
> b/security/integrity/ima/ima_main.c
> index 1d6229b156fb..4fc383479847 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -180,6 +180,34 @@ static void ima_rdwr_violation_check(struct file *file,
> "invalid_pcr", "open_writers");
> }
>
> +/*
> + * Detect file change based on STATX_CHANGE_COOKIE, when supported, and
> + * fallback to detecting file change based on i_version. On filesystems
> + * which do not support either, assume the file changed.
> + */
> +static bool ima_detect_file_change(struct ima_iint_cache *iint,
> + struct inode *inode, struct file *file)
> +{
> + struct kstat stat;
> + int result;
> +
> + result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE,
> + AT_STATX_SYNC_AS_STAT);
> +
> + if (!result && stat.result_mask & STATX_CHANGE_COOKIE &&
> + stat.change_cookie != iint->real_inode.version)
> + return true;
> + else if (!(stat.result_mask & STATX_CHANGE_COOKIE) &&
> + IS_I_VERSION(inode) &&
> + !(inode_eq_iversion(inode, iint->real_inode.version)))
> + return true;
> + else if (!(stat.result_mask & STATX_CHANGE_COOKIE) &&
> + !(IS_I_VERSION(inode)))
> + return true;
> +
> + return false;
> +}
> +
> static void ima_check_last_writer(struct ima_iint_cache *iint,
> struct inode *inode, struct file *file)
> {
> @@ -191,18 +219,13 @@ static void ima_check_last_writer(struct ima_iint_cache
> *iint,
>
> mutex_lock(&iint->mutex);
> if (atomic_read(&inode->i_writecount) == 1) {
> - struct kstat stat;
> -
> clear_bit(IMA_EMITTED_OPENWRITERS, &iint->atomic_flags);
>
> update = test_and_clear_bit(IMA_UPDATE_XATTR,
> &iint->atomic_flags);
> - if ((iint->flags & IMA_NEW_FILE) ||
> - vfs_getattr_nosec(&file->f_path, &stat,
> - STATX_CHANGE_COOKIE,
> - AT_STATX_SYNC_AS_STAT) ||
> - !(stat.result_mask & STATX_CHANGE_COOKIE) ||
> - stat.change_cookie != iint->real_inode.version) {
> +
> + if (iint->flags & IMA_NEW_FILE ||
> + ima_detect_file_change(iint, inode, file)) {
> iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
> iint->measured_pcrs = 0;
> if (update)
> --
> 2.53.0
>
