From db1d1e8b9867aae5c3e61ad7859abfcc4a6fd6c7 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 17 Apr 2023 12:55:51 -0400 Subject: [PATCH] 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 Reviewed-by: Christian Brauner Signed-off-by: Jeff Layton Signed-off-by: Mimi Zohar --- security/integrity/ima/ima_api.c | 9 ++++++--- 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 d3662f4..c45902e 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -13,7 +13,6 @@ #include #include #include -#include #include #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 d66a0a3..365db0e 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -24,7 +24,6 @@ #include #include #include -#include #include #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) -- 2.7.4