Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
ima: fallback to using i_version to detect file change
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.
Reported-by: Frederick Lawler <fred@cloudflare.com>
Fixes: db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get the i_version")
Cc: stable@vger.kernel.org
Reviewed-by: Frederick Lawler <fred@cloudflare.com>
Tested-by: Frederick Lawler <fred@cloudflare.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
+35
-12
+9
-4
security/integrity/ima/ima_api.c
+9
-4
security/integrity/ima/ima_api.c
···
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goto out;
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/*
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* Detecting file change is based on i_version. On filesystems
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* which do not support i_version, support was originally limited
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* to an initial measurement/appraisal/audit, but was modified to
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-
* assume the file changed.
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+
* Detect file change based on STATX_CHANGE_COOKIE, when supported,
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* and fallback to detecting file change based on i_version.
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*
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* On filesystems which did not support i_version, support was
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* originally limited to an initial measurement/appraisal/audit,
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* but was later modified to assume the file changed.
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*/
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result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE,
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AT_STATX_SYNC_AS_STAT);
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if (!result && (stat.result_mask & STATX_CHANGE_COOKIE))
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i_version = stat.change_cookie;
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+
else if (IS_I_VERSION(real_inode))
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i_version = inode_peek_iversion(real_inode);
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+
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hash.hdr.algo = algo;
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hash.hdr.length = hash_digest_size[algo];
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+26
-8
security/integrity/ima/ima_main.c
+26
-8
security/integrity/ima/ima_main.c
···
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"invalid_pcr", "open_writers");
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}
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/*
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* Detect file change based on STATX_CHANGE_COOKIE, when supported, and
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* fallback to detecting file change based on i_version. On filesystems
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* which do not support either, assume the file changed.
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*/
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+
static bool ima_detect_file_change(struct ima_iint_cache *iint,
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struct inode *inode, struct file *file)
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{
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struct kstat stat;
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int result;
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+
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result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE,
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AT_STATX_SYNC_AS_STAT);
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+
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if (!result && stat.result_mask & STATX_CHANGE_COOKIE)
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return stat.change_cookie != iint->real_inode.version;
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+
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if (IS_I_VERSION(inode))
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return !inode_eq_iversion(inode, iint->real_inode.version);
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+
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return true;
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}
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+
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static void ima_check_last_writer(struct ima_iint_cache *iint,
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struct inode *inode, struct file *file)
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{
···
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mutex_lock(&iint->mutex);
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if (atomic_read(&inode->i_writecount) == 1) {
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struct kstat stat;
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-
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clear_bit(IMA_EMITTED_OPENWRITERS, &iint->atomic_flags);
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update = test_and_clear_bit(IMA_UPDATE_XATTR,
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&iint->atomic_flags);
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if ((iint->flags & IMA_NEW_FILE) ||
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vfs_getattr_nosec(&file->f_path, &stat,
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-
STATX_CHANGE_COOKIE,
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AT_STATX_SYNC_AS_STAT) ||
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-
!(stat.result_mask & STATX_CHANGE_COOKIE) ||
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stat.change_cookie != iint->real_inode.version) {
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+
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+
if (iint->flags & IMA_NEW_FILE ||
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ima_detect_file_change(iint, inode, file)) {
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iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
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iint->measured_pcrs = 0;
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if (update)