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-rw-r--r--security/integrity/evm/Kconfig1
-rw-r--r--security/integrity/evm/evm.h19
-rw-r--r--security/integrity/evm/evm_crypto.c4
-rw-r--r--security/integrity/evm/evm_main.c195
4 files changed, 183 insertions, 36 deletions
diff --git a/security/integrity/evm/Kconfig b/security/integrity/evm/Kconfig
index fba9ee359b..861b3bacab 100644
--- a/security/integrity/evm/Kconfig
+++ b/security/integrity/evm/Kconfig
@@ -6,6 +6,7 @@ config EVM
select CRYPTO_HMAC
select CRYPTO_SHA1
select CRYPTO_HASH_INFO
+ select SECURITY_PATH
default n
help
EVM protects a file's security extended attributes against
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 53bd7fec93..eb1a2c343b 100644
--- a/security/integrity/evm/evm.h
+++ b/security/integrity/evm/evm.h
@@ -32,6 +32,25 @@ struct xattr_list {
bool enabled;
};
+#define EVM_NEW_FILE 0x00000001
+#define EVM_IMMUTABLE_DIGSIG 0x00000002
+
+/* EVM integrity metadata associated with an inode */
+struct evm_iint_cache {
+ unsigned long flags;
+ enum integrity_status evm_status:4;
+};
+
+extern struct lsm_blob_sizes evm_blob_sizes;
+
+static inline struct evm_iint_cache *evm_iint_inode(const struct inode *inode)
+{
+ if (unlikely(!inode->i_security))
+ return NULL;
+
+ return inode->i_security + evm_blob_sizes.lbs_inode;
+}
+
extern int evm_initialized;
#define EVM_ATTR_FSUUID 0x0001
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index b1ffd4cc0b..7552d49d07 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -322,10 +322,10 @@ int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
{
const struct evm_ima_xattr_data *xattr_data = NULL;
- struct integrity_iint_cache *iint;
+ struct evm_iint_cache *iint;
int rc = 0;
- iint = integrity_iint_find(inode);
+ iint = evm_iint_inode(inode);
if (iint && (iint->flags & EVM_IMMUTABLE_DIGSIG))
return 1;
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index cc7956d787..81dbade5b9 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -178,14 +178,14 @@ static int is_unsupported_fs(struct dentry *dentry)
static enum integrity_status evm_verify_hmac(struct dentry *dentry,
const char *xattr_name,
char *xattr_value,
- size_t xattr_value_len,
- struct integrity_iint_cache *iint)
+ size_t xattr_value_len)
{
struct evm_ima_xattr_data *xattr_data = NULL;
struct signature_v2_hdr *hdr;
enum integrity_status evm_status = INTEGRITY_PASS;
struct evm_digest digest;
- struct inode *inode;
+ struct inode *inode = d_backing_inode(dentry);
+ struct evm_iint_cache *iint = evm_iint_inode(inode);
int rc, xattr_len, evm_immutable = 0;
if (iint && (iint->evm_status == INTEGRITY_PASS ||
@@ -254,8 +254,6 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
(const char *)xattr_data, xattr_len,
digest.digest, digest.hdr.length);
if (!rc) {
- inode = d_backing_inode(dentry);
-
if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG) {
if (iint)
iint->flags |= EVM_IMMUTABLE_DIGSIG;
@@ -403,7 +401,6 @@ int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
* @xattr_name: requested xattr
* @xattr_value: requested xattr value
* @xattr_value_len: requested xattr value length
- * @iint: inode integrity metadata
*
* Calculate the HMAC for the given dentry and verify it against the stored
* security.evm xattr. For performance, use the xattr value and length
@@ -416,8 +413,7 @@ int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
*/
enum integrity_status evm_verifyxattr(struct dentry *dentry,
const char *xattr_name,
- void *xattr_value, size_t xattr_value_len,
- struct integrity_iint_cache *iint)
+ void *xattr_value, size_t xattr_value_len)
{
if (!evm_key_loaded() || !evm_protected_xattr(xattr_name))
return INTEGRITY_UNKNOWN;
@@ -425,13 +421,8 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry,
if (is_unsupported_fs(dentry))
return INTEGRITY_UNKNOWN;
- if (!iint) {
- iint = integrity_iint_find(d_backing_inode(dentry));
- if (!iint)
- return INTEGRITY_UNKNOWN;
- }
return evm_verify_hmac(dentry, xattr_name, xattr_value,
- xattr_value_len, iint);
+ xattr_value_len);
}
EXPORT_SYMBOL_GPL(evm_verifyxattr);
@@ -448,7 +439,7 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry)
if (!evm_key_loaded() || !S_ISREG(inode->i_mode) || evm_fixmode)
return INTEGRITY_PASS;
- return evm_verify_hmac(dentry, NULL, NULL, 0, NULL);
+ return evm_verify_hmac(dentry, NULL, NULL, 0);
}
/*
@@ -526,14 +517,14 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
evm_status = evm_verify_current_integrity(dentry);
if (evm_status == INTEGRITY_NOXATTRS) {
- struct integrity_iint_cache *iint;
+ struct evm_iint_cache *iint;
/* Exception if the HMAC is not going to be calculated. */
if (evm_hmac_disabled())
return 0;
- iint = integrity_iint_find(d_backing_inode(dentry));
- if (iint && (iint->flags & IMA_NEW_FILE))
+ iint = evm_iint_inode(d_backing_inode(dentry));
+ if (iint && (iint->flags & EVM_NEW_FILE))
return 0;
/* exception for pseudo filesystems */
@@ -581,6 +572,7 @@ out:
* @xattr_name: pointer to the affected extended attribute name
* @xattr_value: pointer to the new extended attribute value
* @xattr_value_len: pointer to the new extended attribute value length
+ * @flags: flags to pass into filesystem operations
*
* Before allowing the 'security.evm' protected xattr to be updated,
* verify the existing value is valid. As only the kernel should have
@@ -588,9 +580,9 @@ out:
* userspace from writing HMAC value. Writing 'security.evm' requires
* requires CAP_SYS_ADMIN privileges.
*/
-int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *xattr_name, const void *xattr_value,
- size_t xattr_value_len)
+static int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name, const void *xattr_value,
+ size_t xattr_value_len, int flags)
{
const struct evm_ima_xattr_data *xattr_data = xattr_value;
@@ -620,8 +612,8 @@ int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
* Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that
* the current value is valid.
*/
-int evm_inode_removexattr(struct mnt_idmap *idmap,
- struct dentry *dentry, const char *xattr_name)
+static int evm_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *xattr_name)
{
/* Policy permits modification of the protected xattrs even though
* there's no HMAC key loaded
@@ -671,9 +663,11 @@ static inline int evm_inode_set_acl_change(struct mnt_idmap *idmap,
* Prevent modifying posix acls causing the EVM HMAC to be re-calculated
* and 'security.evm' xattr updated, unless the existing 'security.evm' is
* valid.
+ *
+ * Return: zero on success, -EPERM on failure.
*/
-int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
- const char *acl_name, struct posix_acl *kacl)
+static int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name, struct posix_acl *kacl)
{
enum integrity_status evm_status;
@@ -712,11 +706,29 @@ int evm_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
return -EPERM;
}
+/**
+ * evm_inode_remove_acl - Protect the EVM extended attribute from posix acls
+ * @idmap: idmap of the mount
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ *
+ * Prevent removing posix acls causing the EVM HMAC to be re-calculated
+ * and 'security.evm' xattr updated, unless the existing 'security.evm' is
+ * valid.
+ *
+ * Return: zero on success, -EPERM on failure.
+ */
+static int evm_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+ const char *acl_name)
+{
+ return evm_inode_set_acl(idmap, dentry, acl_name, NULL);
+}
+
static void evm_reset_status(struct inode *inode)
{
- struct integrity_iint_cache *iint;
+ struct evm_iint_cache *iint;
- iint = integrity_iint_find(inode);
+ iint = evm_iint_inode(inode);
if (iint)
iint->evm_status = INTEGRITY_UNKNOWN;
}
@@ -752,6 +764,7 @@ bool evm_revalidate_status(const char *xattr_name)
* @xattr_name: pointer to the affected extended attribute name
* @xattr_value: pointer to the new extended attribute value
* @xattr_value_len: pointer to the new extended attribute value length
+ * @flags: flags to pass into filesystem operations
*
* Update the HMAC stored in 'security.evm' to reflect the change.
*
@@ -759,8 +772,11 @@ bool evm_revalidate_status(const char *xattr_name)
* __vfs_setxattr_noperm(). The caller of which has taken the inode's
* i_mutex lock.
*/
-void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
- const void *xattr_value, size_t xattr_value_len)
+static void evm_inode_post_setxattr(struct dentry *dentry,
+ const char *xattr_name,
+ const void *xattr_value,
+ size_t xattr_value_len,
+ int flags)
{
if (!evm_revalidate_status(xattr_name))
return;
@@ -780,6 +796,21 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
}
/**
+ * evm_inode_post_set_acl - Update the EVM extended attribute from posix acls
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ * @kacl: pointer to the posix acls
+ *
+ * Update the 'security.evm' xattr with the EVM HMAC re-calculated after setting
+ * posix acls.
+ */
+static void evm_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
+ struct posix_acl *kacl)
+{
+ return evm_inode_post_setxattr(dentry, acl_name, NULL, 0, 0);
+}
+
+/**
* evm_inode_post_removexattr - update 'security.evm' after removing the xattr
* @dentry: pointer to the affected dentry
* @xattr_name: pointer to the affected extended attribute name
@@ -789,7 +820,8 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
* No need to take the i_mutex lock here, as this function is called from
* vfs_removexattr() which takes the i_mutex.
*/
-void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
+static void evm_inode_post_removexattr(struct dentry *dentry,
+ const char *xattr_name)
{
if (!evm_revalidate_status(xattr_name))
return;
@@ -805,6 +837,22 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
evm_update_evmxattr(dentry, xattr_name, NULL, 0);
}
+/**
+ * evm_inode_post_remove_acl - Update the EVM extended attribute from posix acls
+ * @idmap: idmap of the mount
+ * @dentry: pointer to the affected dentry
+ * @acl_name: name of the posix acl
+ *
+ * Update the 'security.evm' xattr with the EVM HMAC re-calculated after
+ * removing posix acls.
+ */
+static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap,
+ struct dentry *dentry,
+ const char *acl_name)
+{
+ evm_inode_post_removexattr(dentry, acl_name);
+}
+
static int evm_attr_change(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr)
{
@@ -828,8 +876,8 @@ static int evm_attr_change(struct mnt_idmap *idmap,
* Permit update of file attributes when files have a valid EVM signature,
* except in the case of them having an immutable portable signature.
*/
-int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *attr)
+static int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
enum integrity_status evm_status;
@@ -870,6 +918,7 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
/**
* evm_inode_post_setattr - update 'security.evm' after modifying metadata
+ * @idmap: idmap of the idmapped mount
* @dentry: pointer to the affected dentry
* @ia_valid: for the UID and GID status
*
@@ -879,7 +928,8 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
* This function is called from notify_change(), which expects the caller
* to lock the inode's i_mutex.
*/
-void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
+static void evm_inode_post_setattr(struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
{
if (!evm_revalidate_status(NULL))
return;
@@ -896,7 +946,7 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
evm_update_evmxattr(dentry, NULL, NULL, 0);
}
-int evm_inode_copy_up_xattr(const char *name)
+static int evm_inode_copy_up_xattr(const char *name)
{
if (strcmp(name, XATTR_NAME_EVM) == 0)
return 1; /* Discard */
@@ -960,6 +1010,42 @@ out:
}
EXPORT_SYMBOL_GPL(evm_inode_init_security);
+static int evm_inode_alloc_security(struct inode *inode)
+{
+ struct evm_iint_cache *iint = evm_iint_inode(inode);
+
+ /* Called by security_inode_alloc(), it cannot be NULL. */
+ iint->flags = 0UL;
+ iint->evm_status = INTEGRITY_UNKNOWN;
+
+ return 0;
+}
+
+static void evm_file_release(struct file *file)
+{
+ struct inode *inode = file_inode(file);
+ struct evm_iint_cache *iint = evm_iint_inode(inode);
+ fmode_t mode = file->f_mode;
+
+ if (!S_ISREG(inode->i_mode) || !(mode & FMODE_WRITE))
+ return;
+
+ if (iint && atomic_read(&inode->i_writecount) == 1)
+ iint->flags &= ~EVM_NEW_FILE;
+}
+
+static void evm_post_path_mknod(struct mnt_idmap *idmap, struct dentry *dentry)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct evm_iint_cache *iint = evm_iint_inode(inode);
+
+ if (!S_ISREG(inode->i_mode))
+ return;
+
+ if (iint)
+ iint->flags |= EVM_NEW_FILE;
+}
+
#ifdef CONFIG_EVM_LOAD_X509
void __init evm_load_x509(void)
{
@@ -999,4 +1085,45 @@ error:
return error;
}
+static struct security_hook_list evm_hooks[] __ro_after_init = {
+ LSM_HOOK_INIT(inode_setattr, evm_inode_setattr),
+ LSM_HOOK_INIT(inode_post_setattr, evm_inode_post_setattr),
+ LSM_HOOK_INIT(inode_copy_up_xattr, evm_inode_copy_up_xattr),
+ LSM_HOOK_INIT(inode_setxattr, evm_inode_setxattr),
+ LSM_HOOK_INIT(inode_post_setxattr, evm_inode_post_setxattr),
+ LSM_HOOK_INIT(inode_set_acl, evm_inode_set_acl),
+ LSM_HOOK_INIT(inode_post_set_acl, evm_inode_post_set_acl),
+ LSM_HOOK_INIT(inode_remove_acl, evm_inode_remove_acl),
+ LSM_HOOK_INIT(inode_post_remove_acl, evm_inode_post_remove_acl),
+ LSM_HOOK_INIT(inode_removexattr, evm_inode_removexattr),
+ LSM_HOOK_INIT(inode_post_removexattr, evm_inode_post_removexattr),
+ LSM_HOOK_INIT(inode_init_security, evm_inode_init_security),
+ LSM_HOOK_INIT(inode_alloc_security, evm_inode_alloc_security),
+ LSM_HOOK_INIT(file_release, evm_file_release),
+ LSM_HOOK_INIT(path_post_mknod, evm_post_path_mknod),
+};
+
+static const struct lsm_id evm_lsmid = {
+ .name = "evm",
+ .id = LSM_ID_EVM,
+};
+
+static int __init init_evm_lsm(void)
+{
+ security_add_hooks(evm_hooks, ARRAY_SIZE(evm_hooks), &evm_lsmid);
+ return 0;
+}
+
+struct lsm_blob_sizes evm_blob_sizes __ro_after_init = {
+ .lbs_inode = sizeof(struct evm_iint_cache),
+ .lbs_xattr_count = 1,
+};
+
+DEFINE_LSM(evm) = {
+ .name = "evm",
+ .init = init_evm_lsm,
+ .order = LSM_ORDER_LAST,
+ .blobs = &evm_blob_sizes,
+};
+
late_initcall(init_evm);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 17:17:33 +0000