diff options
| author | Jeff Layton <jlayton@kernel.org> | 2023-04-17 12:55:51 -0400 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.ibm.com> | 2023-05-23 18:07:34 -0400 |
| commit | db1d1e8b9867aae5c3e61ad7859abfcc4a6fd6c7 (patch) | |
| tree | e8383eaf530258062aa0aa585adef06b5f9c3f38 /security | |
| parent | f1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6 (diff) | |
| download | lwn-db1d1e8b9867aae5c3e61ad7859abfcc4a6fd6c7.tar.gz lwn-db1d1e8b9867aae5c3e61ad7859abfcc4a6fd6c7.zip | |
IMA: use vfs_getattr_nosec to get the i_version
IMA currently accesses the i_version out of the inode directly when it
does a measurement. This is fine for most simple filesystems, but can be
problematic with more complex setups (e.g. overlayfs).
Make IMA instead call vfs_getattr_nosec to get this info. This allows
the filesystem to determine whether and how to report the i_version, and
should allow IMA to work properly with a broader class of filesystems in
the future.
Reported-and-Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/ima/ima_api.c | 9 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 12 |
2 files changed, 14 insertions, 7 deletions
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index d3662f4acadc..c45902e72044 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -13,7 +13,6 @@ #include <linux/fs.h> #include <linux/xattr.h> #include <linux/evm.h> -#include <linux/iversion.h> #include <linux/fsverity.h> #include "ima.h" @@ -246,10 +245,11 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, struct inode *inode = file_inode(file); const char *filename = file->f_path.dentry->d_name.name; struct ima_max_digest_data hash; + struct kstat stat; int result = 0; int length; void *tmpbuf; - u64 i_version; + u64 i_version = 0; /* * Always collect the modsig, because IMA might have already collected @@ -268,7 +268,10 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, * to an initial measurement/appraisal/audit, but was modified to * assume the file changed. */ - i_version = inode_query_iversion(inode); + 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; 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 d66a0a36415e..365db0e43d7c 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -24,7 +24,6 @@ #include <linux/slab.h> #include <linux/xattr.h> #include <linux/ima.h> -#include <linux/iversion.h> #include <linux/fs.h> #include "ima.h" @@ -164,11 +163,16 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint, mutex_lock(&iint->mutex); if (atomic_read(&inode->i_writecount) == 1) { + struct kstat stat; + update = test_and_clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); - if (!IS_I_VERSION(inode) || - !inode_eq_iversion(inode, iint->version) || - (iint->flags & IMA_NEW_FILE)) { + 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->version) { iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE); iint->measured_pcrs = 0; if (update) |