From 34996e42f82bfd60bc2c191e5cae3c6ab233ec6c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 7 Aug 2024 15:11:27 +0200 Subject: Merging upstream version 6.9.7. Signed-off-by: Daniel Baumann --- security/integrity/evm/Kconfig | 1 + security/integrity/evm/evm.h | 19 ++++ security/integrity/evm/evm_crypto.c | 4 +- security/integrity/evm/evm_main.c | 195 +++++++++++++++++++++++++++++------- 4 files changed, 183 insertions(+), 36 deletions(-) (limited to 'security/integrity/evm') 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; @@ -779,6 +795,21 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); } +/** + * 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 @@ -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); -- cgit v1.2.3