From: Roberto Sassu <roberto.sassu@huawei.com>
To: <zohar@linux.ibm.com>, <mjg59@google.com>
Cc: <linux-integrity@vger.kernel.org>,
<linux-security-module@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Roberto Sassu <roberto.sassu@huawei.com>,
Casey Schaufler <casey@schaufler-ca.com>
Subject: [PATCH v5 04/12] ima: Move ima_reset_appraise_flags() call to post hooks
Date: Wed, 7 Apr 2021 12:52:44 +0200 [thread overview]
Message-ID: <20210407105252.30721-5-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20210407105252.30721-1-roberto.sassu@huawei.com>
ima_inode_setxattr() and ima_inode_removexattr() hooks are called before an
operation is performed. Thus, ima_reset_appraise_flags() should not be
called there, as flags might be unnecessarily reset if the operation is
denied.
This patch introduces the post hooks ima_inode_post_setxattr() and
ima_inode_post_removexattr(), and adds the call to
ima_reset_appraise_flags() in the new functions.
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
fs/xattr.c | 2 ++
include/linux/ima.h | 18 ++++++++++++++++++
security/integrity/ima/ima_appraise.c | 25 ++++++++++++++++++++++---
security/security.c | 1 +
4 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/fs/xattr.c b/fs/xattr.c
index b3444e06cded..81847f132d26 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -16,6 +16,7 @@
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/evm.h>
+#include <linux/ima.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fsnotify.h>
@@ -502,6 +503,7 @@ __vfs_removexattr_locked(struct user_namespace *mnt_userns,
if (!error) {
fsnotify_xattr(dentry);
+ ima_inode_post_removexattr(dentry, name);
evm_inode_post_removexattr(dentry, name);
}
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 61d5723ec303..5e059da43857 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -171,7 +171,13 @@ extern void ima_inode_post_setattr(struct user_namespace *mnt_userns,
struct dentry *dentry);
extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
const void *xattr_value, size_t xattr_value_len);
+extern void ima_inode_post_setxattr(struct dentry *dentry,
+ const char *xattr_name,
+ const void *xattr_value,
+ size_t xattr_value_len);
extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
+extern void ima_inode_post_removexattr(struct dentry *dentry,
+ const char *xattr_name);
#else
static inline bool is_ima_appraise_enabled(void)
{
@@ -192,11 +198,23 @@ static inline int ima_inode_setxattr(struct dentry *dentry,
return 0;
}
+static inline void ima_inode_post_setxattr(struct dentry *dentry,
+ const char *xattr_name,
+ const void *xattr_value,
+ size_t xattr_value_len)
+{
+}
+
static inline int ima_inode_removexattr(struct dentry *dentry,
const char *xattr_name)
{
return 0;
}
+
+static inline void ima_inode_post_removexattr(struct dentry *dentry,
+ const char *xattr_name)
+{
+}
#endif /* CONFIG_IMA_APPRAISE */
#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 565e33ff19d0..1f029e4c8d7f 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -577,21 +577,40 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
if (result == 1) {
if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
return -EINVAL;
- ima_reset_appraise_flags(d_backing_inode(dentry),
- xvalue->type == EVM_IMA_XATTR_DIGSIG);
result = 0;
}
return result;
}
+void ima_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
+ const void *xattr_value, size_t xattr_value_len)
+{
+ const struct evm_ima_xattr_data *xvalue = xattr_value;
+ int result;
+
+ result = ima_protect_xattr(dentry, xattr_name, xattr_value,
+ xattr_value_len);
+ if (result == 1)
+ ima_reset_appraise_flags(d_backing_inode(dentry),
+ xvalue->type == EVM_IMA_XATTR_DIGSIG);
+}
+
int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
{
int result;
result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
if (result == 1) {
- ima_reset_appraise_flags(d_backing_inode(dentry), 0);
result = 0;
}
return result;
}
+
+void ima_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
+{
+ int result;
+
+ result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
+ if (result == 1)
+ ima_reset_appraise_flags(d_backing_inode(dentry), 0);
+}
diff --git a/security/security.c b/security/security.c
index 5ac96b16f8fa..efb1f874dc41 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1319,6 +1319,7 @@ void security_inode_post_setxattr(struct dentry *dentry, const char *name,
if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
return;
call_void_hook(inode_post_setxattr, dentry, name, value, size, flags);
+ ima_inode_post_setxattr(dentry, name, value, size);
evm_inode_post_setxattr(dentry, name, value, size);
}
--
2.26.2
next prev parent reply other threads:[~2021-04-07 10:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 10:52 [PATCH v5 00/12] evm: Improve usability of portable signatures Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 01/12] evm: Execute evm_inode_init_security() only when an HMAC key is loaded Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 02/12] evm: Load EVM key in ima_load_x509() to avoid appraisal Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 03/12] evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded Roberto Sassu
2021-04-30 20:28 ` Mimi Zohar
2021-04-07 10:52 ` Roberto Sassu [this message]
2021-04-07 16:17 ` [PATCH v5 04/12] ima: Move ima_reset_appraise_flags() call to post hooks Casey Schaufler
2021-04-07 16:31 ` Roberto Sassu
2021-04-26 19:49 ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 05/12] evm: Introduce evm_status_revalidate() Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 06/12] evm: Ignore INTEGRITY_NOLABEL/INTEGRITY_NOXATTRS if conditions are safe Roberto Sassu
2021-05-03 0:12 ` Mimi Zohar
2021-05-03 7:55 ` Roberto Sassu
2021-05-03 12:07 ` Mimi Zohar
2021-05-03 14:15 ` Roberto Sassu
2021-05-03 14:34 ` Mimi Zohar
2021-05-04 13:16 ` Roberto Sassu
2021-05-04 13:45 ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 07/12] evm: Allow xattr/attr operations for portable signatures Roberto Sassu
2021-05-03 0:12 ` Mimi Zohar
2021-05-04 14:28 ` Roberto Sassu
2021-05-04 14:49 ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 08/12] evm: Pass user namespace to set/remove xattr hooks Roberto Sassu
2021-04-07 12:06 ` Christian Brauner
2021-04-07 10:52 ` [PATCH v5 09/12] evm: Allow setxattr() and setattr() for unmodified metadata Roberto Sassu
2021-04-07 12:05 ` Christian Brauner
2021-04-07 15:23 ` kernel test robot
2021-04-07 18:14 ` kernel test robot
2021-04-07 19:28 ` [RESEND][PATCH " Roberto Sassu
2021-05-03 13:00 ` [PATCH " Mimi Zohar
2021-05-03 14:48 ` Roberto Sassu
2021-05-03 15:13 ` Mimi Zohar
2021-05-03 15:30 ` Roberto Sassu
2021-05-03 15:11 ` Roberto Sassu
2021-05-03 15:26 ` Mimi Zohar
2021-05-03 15:32 ` Roberto Sassu
2021-05-03 15:48 ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 10/12] ima: Allow imasig requirement to be satisfied by EVM portable signatures Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 11/12] ima: Introduce template field evmsig and write to field sig as fallback Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 12/12] ima: Don't remove security.ima if file must not be appraised Roberto Sassu
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