From bad5247a2c4f7eab6fb922af3362740a562dc665 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:30:49 +0100 Subject: ima: Align ima_inode_post_setattr() definition with LSM infrastructure Change ima_inode_post_setattr() definition, so that it can be registered as implementation of the inode_post_setattr hook (to be introduced). Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger Reviewed-by: Casey Schaufler Reviewed-by: Mimi Zohar Acked-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/attr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index 5a13f0c8495f..b53ae408ad4f 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -502,7 +502,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (!error) { fsnotify_change(dentry, ia_valid); - ima_inode_post_setattr(idmap, dentry); + ima_inode_post_setattr(idmap, dentry, ia_valid); evm_inode_post_setattr(dentry, ia_valid); } -- cgit v1.2.3 From 784111d0093e007950cc20033daf3d74ac388821 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:30:54 +0100 Subject: evm: Align evm_inode_post_setattr() definition with LSM infrastructure Change evm_inode_post_setattr() definition, so that it can be registered as implementation of the inode_post_setattr hook (to be introduced). Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger Reviewed-by: Casey Schaufler Reviewed-by: Mimi Zohar Acked-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/attr.c | 2 +- include/linux/evm.h | 6 ++++-- security/integrity/evm/evm_main.c | 4 +++- 3 files changed, 8 insertions(+), 4 deletions(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index b53ae408ad4f..adeba0ec40f1 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -503,7 +503,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (!error) { fsnotify_change(dentry, ia_valid); ima_inode_post_setattr(idmap, dentry, ia_valid); - evm_inode_post_setattr(dentry, ia_valid); + evm_inode_post_setattr(idmap, dentry, ia_valid); } return error; diff --git a/include/linux/evm.h b/include/linux/evm.h index 36ec884320d9..5cc386312b5a 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -23,7 +23,8 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry, struct integrity_iint_cache *iint); extern int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr); -extern void evm_inode_post_setattr(struct dentry *dentry, int ia_valid); +extern void evm_inode_post_setattr(struct mnt_idmap *idmap, + struct dentry *dentry, int ia_valid); extern int evm_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, const void *value, size_t size); @@ -98,7 +99,8 @@ static inline int evm_inode_setattr(struct mnt_idmap *idmap, return 0; } -static inline void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) +static inline void evm_inode_post_setattr(struct mnt_idmap *idmap, + struct dentry *dentry, int ia_valid) { return; } diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index cc7956d7878b..ac34f21122cd 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -870,6 +870,7 @@ 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 +880,8 @@ 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) +void evm_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + int ia_valid) { if (!evm_revalidate_status(NULL)) return; -- cgit v1.2.3 From 77fa6f314f0376176ef6bf3d84403e0d8b54ce28 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:30:58 +0100 Subject: security: Introduce inode_post_setattr hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_setattr hook. At inode_setattr hook, EVM verifies the file's existing HMAC value. At inode_post_setattr, EVM re-calculates the file's HMAC based on the modified file attributes and other file metadata. Other LSMs could similarly take some action after successful file attribute change. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Acked-by: Casey Schaufler Acked-by: Christian Brauner Signed-off-by: Paul Moore --- fs/attr.c | 1 + include/linux/lsm_hook_defs.h | 2 ++ include/linux/security.h | 7 +++++++ security/security.c | 16 ++++++++++++++++ 4 files changed, 26 insertions(+) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index adeba0ec40f1..990e1b3a3c91 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -502,6 +502,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (!error) { fsnotify_change(dentry, ia_valid); + security_inode_post_setattr(idmap, dentry, ia_valid); ima_inode_post_setattr(idmap, dentry, ia_valid); evm_inode_post_setattr(idmap, dentry, ia_valid); } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index b00b16d58413..a0e9e48015a4 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -137,6 +137,8 @@ LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode, LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask) LSM_HOOK(int, 0, inode_setattr, struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr) +LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap, + struct dentry *dentry, int ia_valid) LSM_HOOK(int, 0, inode_getattr, const struct path *path) LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap, struct dentry *dentry, const char *name, const void *value, diff --git a/include/linux/security.h b/include/linux/security.h index d0eb20f90b26..56c841aa3994 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -361,6 +361,8 @@ int security_inode_follow_link(struct dentry *dentry, struct inode *inode, int security_inode_permission(struct inode *inode, int mask); int security_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr); +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + int ia_valid); int security_inode_getattr(const struct path *path); int security_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, @@ -879,6 +881,11 @@ static inline int security_inode_setattr(struct mnt_idmap *idmap, return 0; } +static inline void +security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + int ia_valid) +{ } + static inline int security_inode_getattr(const struct path *path) { return 0; diff --git a/security/security.c b/security/security.c index 9dc601d45960..56527d5415e2 100644 --- a/security/security.c +++ b/security/security.c @@ -2222,6 +2222,22 @@ int security_inode_setattr(struct mnt_idmap *idmap, } EXPORT_SYMBOL_GPL(security_inode_setattr); +/** + * security_inode_post_setattr() - Update the inode after a setattr operation + * @idmap: idmap of the mount + * @dentry: file + * @ia_valid: file attributes set + * + * Update inode security field after successful setting file attributes. + */ +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + int ia_valid) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_setattr, idmap, dentry, ia_valid); +} + /** * security_inode_getattr() - Check if getting file attributes is allowed * @path: file -- cgit v1.2.3 From 84594c9ecdca7ca595bc50e315093cb76921fd8e Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:31:09 +0100 Subject: ima: Move IMA-Appraisal to LSM infrastructure A few additional IMA hooks are needed to reset the cached appraisal status, causing the file's integrity to be re-evaluated on next access. Register these IMA-appraisal only functions separately from the rest of IMA functions, as appraisal is a separate feature not necessarily enabled in the kernel configuration. Reuse the same approach as for other IMA functions, move hardcoded calls from various places in the kernel to the LSM infrastructure. Declare the functions as static and register them as hook implementations in init_ima_appraise_lsm(), called by init_ima_lsm(). Also move the inline function ima_inode_remove_acl() from the public ima.h header to ima_appraise.c. Signed-off-by: Roberto Sassu Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Reviewed-by: Casey Schaufler Acked-by: Christian Brauner Acked-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/attr.c | 2 -- include/linux/ima.h | 55 ----------------------------------- security/integrity/ima/ima.h | 5 ++++ security/integrity/ima/ima_appraise.c | 38 ++++++++++++++++++------ security/integrity/ima/ima_main.c | 1 + security/security.c | 13 --------- 6 files changed, 35 insertions(+), 79 deletions(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index 990e1b3a3c91..7e97313e7f70 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -17,7 +17,6 @@ #include #include #include -#include #include "internal.h" @@ -503,7 +502,6 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (!error) { fsnotify_change(dentry, ia_valid); security_inode_post_setattr(idmap, dentry, ia_valid); - ima_inode_post_setattr(idmap, dentry, ia_valid); evm_inode_post_setattr(idmap, dentry, ia_valid); } diff --git a/include/linux/ima.h b/include/linux/ima.h index 23ae24b60ecf..0bae61a15b60 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -92,66 +92,11 @@ static inline void ima_add_kexec_buffer(struct kimage *image) #ifdef CONFIG_IMA_APPRAISE extern bool is_ima_appraise_enabled(void); -extern void ima_inode_post_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, int ia_valid); -extern int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, - const char *xattr_name, const void *xattr_value, - size_t xattr_value_len, int flags); -extern int ima_inode_set_acl(struct mnt_idmap *idmap, - struct dentry *dentry, const char *acl_name, - struct posix_acl *kacl); -static inline int ima_inode_remove_acl(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *acl_name) -{ - return ima_inode_set_acl(idmap, dentry, acl_name, NULL); -} - -extern int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, - const char *xattr_name); #else static inline bool is_ima_appraise_enabled(void) { return 0; } - -static inline void ima_inode_post_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, int ia_valid) -{ - return; -} - -static inline int ima_inode_setxattr(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *xattr_name, - const void *xattr_value, - size_t xattr_value_len, - int flags) -{ - return 0; -} - -static inline int ima_inode_set_acl(struct mnt_idmap *idmap, - struct dentry *dentry, const char *acl_name, - struct posix_acl *kacl) -{ - - return 0; -} - -static inline int ima_inode_removexattr(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *xattr_name) -{ - return 0; -} - -static inline int ima_inode_remove_acl(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *acl_name) -{ - return 0; -} #endif /* CONFIG_IMA_APPRAISE */ #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c0412100023e..a27fc10f84f7 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -334,6 +334,7 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value, int xattr_len); int ima_read_xattr(struct dentry *dentry, struct evm_ima_xattr_data **xattr_value, int xattr_len); +void __init init_ima_appraise_lsm(const struct lsm_id *lsmid); #else static inline int ima_check_blacklist(struct integrity_iint_cache *iint, @@ -385,6 +386,10 @@ static inline int ima_read_xattr(struct dentry *dentry, return 0; } +static inline void __init init_ima_appraise_lsm(const struct lsm_id *lsmid) +{ +} + #endif /* CONFIG_IMA_APPRAISE */ #ifdef CONFIG_IMA_APPRAISE_MODSIG diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 36abc84ba299..076451109637 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -636,8 +636,8 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) * This function is called from notify_change(), which expects the caller * to lock the inode's i_mutex. */ -void ima_inode_post_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, int ia_valid) +static void ima_inode_post_setattr(struct mnt_idmap *idmap, + struct dentry *dentry, int ia_valid) { struct inode *inode = d_backing_inode(dentry); struct integrity_iint_cache *iint; @@ -750,9 +750,9 @@ static int validate_hash_algo(struct dentry *dentry, return -EACCES; } -int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, - const char *xattr_name, const void *xattr_value, - size_t xattr_value_len, int flags) +static int ima_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 *xvalue = xattr_value; int digsig = 0; @@ -781,8 +781,8 @@ int ima_inode_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, return result; } -int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, - const char *acl_name, struct posix_acl *kacl) +static int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) { if (evm_revalidate_status(acl_name)) ima_reset_appraise_flags(d_backing_inode(dentry), 0); @@ -790,8 +790,8 @@ int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, return 0; } -int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, - const char *xattr_name) +static int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, + const char *xattr_name) { int result; @@ -803,3 +803,23 @@ int ima_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, } return result; } + +static int ima_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, + const char *acl_name) +{ + return ima_inode_set_acl(idmap, dentry, acl_name, NULL); +} + +static struct security_hook_list ima_appraise_hooks[] __ro_after_init = { + LSM_HOOK_INIT(inode_post_setattr, ima_inode_post_setattr), + LSM_HOOK_INIT(inode_setxattr, ima_inode_setxattr), + LSM_HOOK_INIT(inode_set_acl, ima_inode_set_acl), + LSM_HOOK_INIT(inode_removexattr, ima_inode_removexattr), + LSM_HOOK_INIT(inode_remove_acl, ima_inode_remove_acl), +}; + +void __init init_ima_appraise_lsm(const struct lsm_id *lsmid) +{ + security_add_hooks(ima_appraise_hooks, ARRAY_SIZE(ima_appraise_hooks), + lsmid); +} diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index d0826e864c29..b8b8891a9379 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1182,6 +1182,7 @@ static const struct lsm_id ima_lsmid = { static int __init init_ima_lsm(void) { security_add_hooks(ima_hooks, ARRAY_SIZE(ima_hooks), &ima_lsmid); + init_ima_appraise_lsm(&ima_lsmid); return 0; } diff --git a/security/security.c b/security/security.c index 8495890a5a37..bed659b53e59 100644 --- a/security/security.c +++ b/security/security.c @@ -20,7 +20,6 @@ #include #include #include -#include #include #include #include @@ -2308,9 +2307,6 @@ int security_inode_setxattr(struct mnt_idmap *idmap, if (ret == 1) ret = cap_inode_setxattr(dentry, name, value, size, flags); - if (ret) - return ret; - ret = ima_inode_setxattr(idmap, dentry, name, value, size, flags); if (ret) return ret; return evm_inode_setxattr(idmap, dentry, name, value, size, flags); @@ -2338,9 +2334,6 @@ int security_inode_set_acl(struct mnt_idmap *idmap, return 0; ret = call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name, kacl); - if (ret) - return ret; - ret = ima_inode_set_acl(idmap, dentry, acl_name, kacl); if (ret) return ret; return evm_inode_set_acl(idmap, dentry, acl_name, kacl); @@ -2401,9 +2394,6 @@ int security_inode_remove_acl(struct mnt_idmap *idmap, if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; ret = call_int_hook(inode_remove_acl, 0, idmap, dentry, acl_name); - if (ret) - return ret; - ret = ima_inode_remove_acl(idmap, dentry, acl_name); if (ret) return ret; return evm_inode_remove_acl(idmap, dentry, acl_name); @@ -2503,9 +2493,6 @@ int security_inode_removexattr(struct mnt_idmap *idmap, ret = call_int_hook(inode_removexattr, 1, idmap, dentry, name); if (ret == 1) ret = cap_inode_removexattr(idmap, dentry, name); - if (ret) - return ret; - ret = ima_inode_removexattr(idmap, dentry, name); if (ret) return ret; return evm_inode_removexattr(idmap, dentry, name); -- cgit v1.2.3 From 9238311176115aac1b1a86e8e968c04ebec747a1 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:31:10 +0100 Subject: evm: Move to LSM infrastructure As for IMA, move hardcoded EVM function calls from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'evm' (last and always enabled like 'ima'). The order in the Makefile ensures that 'evm' hooks are executed after 'ima' ones. Make EVM functions as static (except for evm_inode_init_security(), which is exported), and register them as hook implementations in init_evm_lsm(). Also move the inline functions evm_inode_remove_acl(), evm_inode_post_remove_acl(), and evm_inode_post_set_acl() from the public evm.h header to evm_main.c. Unlike before (see commit to move IMA to the LSM infrastructure), evm_inode_post_setattr(), evm_inode_post_set_acl(), evm_inode_post_remove_acl(), and evm_inode_post_removexattr() are not executed for private inodes. Finally, add the LSM_ID_EVM case in lsm_list_modules_test.c Signed-off-by: Roberto Sassu Reviewed-by: Casey Schaufler Acked-by: Christian Brauner Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Acked-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/attr.c | 2 - fs/posix_acl.c | 3 - fs/xattr.c | 2 - include/linux/evm.h | 113 -------------------- include/uapi/linux/lsm.h | 1 + security/integrity/evm/evm_main.c | 118 ++++++++++++++++++--- security/security.c | 43 ++------ .../testing/selftests/lsm/lsm_list_modules_test.c | 3 + 8 files changed, 116 insertions(+), 169 deletions(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index 7e97313e7f70..4d0d75953107 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -16,7 +16,6 @@ #include #include #include -#include #include "internal.h" @@ -502,7 +501,6 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (!error) { fsnotify_change(dentry, ia_valid); security_inode_post_setattr(idmap, dentry, ia_valid); - evm_inode_post_setattr(idmap, dentry, ia_valid); } return error; diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 0d2371240c1b..5c90239e3f2b 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -26,7 +26,6 @@ #include #include #include -#include #include #include @@ -1138,7 +1137,6 @@ retry_deleg: if (!error) { fsnotify_xattr(dentry); security_inode_post_set_acl(dentry, acl_name, kacl); - evm_inode_post_set_acl(dentry, acl_name, kacl); } out_inode_unlock: @@ -1247,7 +1245,6 @@ retry_deleg: if (!error) { fsnotify_xattr(dentry); security_inode_post_remove_acl(idmap, dentry, acl_name); - evm_inode_post_remove_acl(idmap, dentry, acl_name); } out_inode_unlock: diff --git a/fs/xattr.c b/fs/xattr.c index f891c260a971..f8b643f91a98 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include #include @@ -557,7 +556,6 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, fsnotify_xattr(dentry); security_inode_post_removexattr(dentry, name); - evm_inode_post_removexattr(dentry, name); out: return error; diff --git a/include/linux/evm.h b/include/linux/evm.h index 3faabdd47852..cb481eccc967 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -21,45 +21,6 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry, void *xattr_value, size_t xattr_value_len, struct integrity_iint_cache *iint); -extern int evm_inode_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, struct iattr *attr); -extern void evm_inode_post_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, int ia_valid); -extern int evm_inode_setxattr(struct mnt_idmap *idmap, - struct dentry *dentry, const char *name, - const void *value, size_t size, int flags); -extern void evm_inode_post_setxattr(struct dentry *dentry, - const char *xattr_name, - const void *xattr_value, - size_t xattr_value_len, - int flags); -extern int evm_inode_copy_up_xattr(const char *name); -extern int evm_inode_removexattr(struct mnt_idmap *idmap, - struct dentry *dentry, const char *xattr_name); -extern void evm_inode_post_removexattr(struct dentry *dentry, - const char *xattr_name); -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); -} -extern int evm_inode_set_acl(struct mnt_idmap *idmap, - struct dentry *dentry, const char *acl_name, - struct posix_acl *kacl); -static inline 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 inline 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); -} - int evm_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count); @@ -94,80 +55,6 @@ static inline enum integrity_status evm_verifyxattr(struct dentry *dentry, } #endif -static inline int evm_inode_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, struct iattr *attr) -{ - return 0; -} - -static inline void evm_inode_post_setattr(struct mnt_idmap *idmap, - struct dentry *dentry, int ia_valid) -{ - return; -} - -static inline int evm_inode_setxattr(struct mnt_idmap *idmap, - struct dentry *dentry, const char *name, - const void *value, size_t size, int flags) -{ - return 0; -} - -static inline void evm_inode_post_setxattr(struct dentry *dentry, - const char *xattr_name, - const void *xattr_value, - size_t xattr_value_len, - int flags) -{ - return; -} - -static inline int evm_inode_copy_up_xattr(const char *name) -{ - return 0; -} - -static inline int evm_inode_removexattr(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *xattr_name) -{ - return 0; -} - -static inline void evm_inode_post_removexattr(struct dentry *dentry, - const char *xattr_name) -{ - return; -} - -static inline void evm_inode_post_remove_acl(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *acl_name) -{ - return; -} - -static inline int evm_inode_set_acl(struct mnt_idmap *idmap, - struct dentry *dentry, const char *acl_name, - struct posix_acl *kacl) -{ - return 0; -} - -static inline int evm_inode_remove_acl(struct mnt_idmap *idmap, - struct dentry *dentry, - const char *acl_name) -{ - return 0; -} - -static inline void evm_inode_post_set_acl(struct dentry *dentry, - const char *acl_name, - struct posix_acl *kacl) -{ - return; -} - static inline int evm_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h index b3b7fd699b63..33d8c9f4aa6b 100644 --- a/include/uapi/linux/lsm.h +++ b/include/uapi/linux/lsm.h @@ -63,6 +63,7 @@ struct lsm_ctx { #define LSM_ID_BPF 109 #define LSM_ID_LANDLOCK 110 #define LSM_ID_IMA 111 +#define LSM_ID_EVM 112 /* * LSM_ATTR_XXX definitions identify different LSM attributes diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index d35143179699..0a089af83a45 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -589,9 +589,9 @@ 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, int flags) +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; @@ -621,8 +621,8 @@ 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 @@ -672,9 +672,11 @@ 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; @@ -713,6 +715,24 @@ 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; @@ -761,9 +781,11 @@ 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, - int flags) +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; @@ -782,6 +804,21 @@ 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 @@ -792,7 +829,8 @@ 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; @@ -808,6 +846,22 @@ 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) { @@ -831,8 +885,8 @@ 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; @@ -883,8 +937,8 @@ 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 mnt_idmap *idmap, 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; @@ -901,7 +955,7 @@ void evm_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 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 */ @@ -1004,4 +1058,36 @@ 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), +}; + +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; +} + +DEFINE_LSM(evm) = { + .name = "evm", + .init = init_evm_lsm, + .order = LSM_ORDER_LAST, +}; + late_initcall(init_evm); diff --git a/security/security.c b/security/security.c index bed659b53e59..59cb0e6cbae3 100644 --- a/security/security.c +++ b/security/security.c @@ -20,13 +20,13 @@ #include #include #include -#include #include #include #include #include #include #include +#include #include #include @@ -50,7 +50,8 @@ (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \ (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \ (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_IMA) ? 1 : 0)) + (IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_EVM) ? 1 : 0)) /* * These are descriptions of the reasons that can be passed to the @@ -1740,10 +1741,6 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, if (!xattr_count) goto out; - ret = evm_inode_init_security(inode, dir, qstr, new_xattrs, - &xattr_count); - if (ret) - goto out; ret = initxattrs(inode, new_xattrs, fs_data); out: for (; xattr_count > 0; xattr_count--) @@ -2235,14 +2232,9 @@ int security_inode_permission(struct inode *inode, int mask) int security_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr) { - int ret; - if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; - ret = call_int_hook(inode_setattr, 0, idmap, dentry, attr); - if (ret) - return ret; - return evm_inode_setattr(idmap, dentry, attr); + return call_int_hook(inode_setattr, 0, idmap, dentry, attr); } EXPORT_SYMBOL_GPL(security_inode_setattr); @@ -2307,9 +2299,7 @@ int security_inode_setxattr(struct mnt_idmap *idmap, if (ret == 1) ret = cap_inode_setxattr(dentry, name, value, size, flags); - if (ret) - return ret; - return evm_inode_setxattr(idmap, dentry, name, value, size, flags); + return ret; } /** @@ -2328,15 +2318,10 @@ int security_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) { - int ret; - if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; - ret = call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name, - kacl); - if (ret) - return ret; - return evm_inode_set_acl(idmap, dentry, acl_name, kacl); + return call_int_hook(inode_set_acl, 0, idmap, dentry, acl_name, + kacl); } /** @@ -2389,14 +2374,9 @@ int security_inode_get_acl(struct mnt_idmap *idmap, int security_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) { - int ret; - if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; - ret = call_int_hook(inode_remove_acl, 0, idmap, dentry, acl_name); - if (ret) - return ret; - return evm_inode_remove_acl(idmap, dentry, acl_name); + return call_int_hook(inode_remove_acl, 0, idmap, dentry, acl_name); } /** @@ -2432,7 +2412,6 @@ 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); - evm_inode_post_setxattr(dentry, name, value, size, flags); } /** @@ -2493,9 +2472,7 @@ int security_inode_removexattr(struct mnt_idmap *idmap, ret = call_int_hook(inode_removexattr, 1, idmap, dentry, name); if (ret == 1) ret = cap_inode_removexattr(idmap, dentry, name); - if (ret) - return ret; - return evm_inode_removexattr(idmap, dentry, name); + return ret; } /** @@ -2699,7 +2676,7 @@ int security_inode_copy_up_xattr(const char *name) return rc; } - return evm_inode_copy_up_xattr(name); + return LSM_RET_DEFAULT(inode_copy_up_xattr); } EXPORT_SYMBOL(security_inode_copy_up_xattr); diff --git a/tools/testing/selftests/lsm/lsm_list_modules_test.c b/tools/testing/selftests/lsm/lsm_list_modules_test.c index 17333787cb2f..4d5d4cee2586 100644 --- a/tools/testing/selftests/lsm/lsm_list_modules_test.c +++ b/tools/testing/selftests/lsm/lsm_list_modules_test.c @@ -125,6 +125,9 @@ TEST(correct_lsm_list_modules) case LSM_ID_IMA: name = "ima"; break; + case LSM_ID_EVM: + name = "evm"; + break; default: name = "INVALID"; break; -- cgit v1.2.3