From 4849cd6fa33a23c787d7b807fb40fb43ba268869 Mon Sep 17 00:00:00 2001 From: Lokesh Gidra Date: Fri, 8 Jan 2021 14:22:20 -0800 Subject: [PATCH] BACKPORT: security: add inode_init_security_anon() LSM hook This change adds a new LSM hook, inode_init_security_anon(), that will be used while creating secure anonymous inodes. The hook allows/denies its creation and assigns a security context to the inode. The new hook accepts an optional context_inode parameter that callers can use to provide additional contextual information to security modules for granting/denying permission to create an anon-inode of the same type. This context_inode's security_context can also be used to initialize the newly created anon-inode's security_context. Signed-off-by: Lokesh Gidra Reviewed-by: Eric Biggers Signed-off-by: Paul Moore (cherry picked from commit 215b674b84dd052098fe6389e32a5afaff8b4d56) Conflicts: include/linux/lsm_hook_defs.h (1. Added LSM hook in lsm_hook.h and removd lsm_hook_defs.h as per 98e828a0650f348be85728c69875260cf78069e6, which is not merged here) Signed-off-by: Lokesh Gidra Bug: 160737021 Bug: 169683130 Change-Id: I83fe318c891f034b4dd7f3f357cc74964b55ffc8 --- include/linux/lsm_hooks.h | 13 +++++++++++++ include/linux/security.h | 10 ++++++++++ security/security.c | 8 ++++++++ 3 files changed, 31 insertions(+) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index ae2e9b409186..1412eec56327 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -215,6 +215,15 @@ * Returns 0 if @name and @value have been successfully set, * -EOPNOTSUPP if no security attribute is needed, or * -ENOMEM on memory allocation failure. + * @inode_init_security_anon: + * Set up the incore security field for the new anonymous inode + * and return whether the inode creation is permitted by the security + * module or not. + * @inode contains the inode structure + * @name name of the anonymous inode class + * @context_inode optional related inode + * Returns 0 on success, -EACCES if the security module denies the + * creation of this inode, or another -errno upon other errors. * @inode_create: * Check permission to create a regular file. * @dir contains inode structure of the parent of the new file. @@ -1558,6 +1567,9 @@ union security_list_options { const struct qstr *qstr, const char **name, void **value, size_t *len); + int (*inode_init_security_anon)(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode); int (*inode_create)(struct inode *dir, struct dentry *dentry, umode_t mode); int (*inode_link)(struct dentry *old_dentry, struct inode *dir, @@ -1892,6 +1904,7 @@ struct security_hook_heads { struct hlist_head inode_alloc_security; struct hlist_head inode_free_security; struct hlist_head inode_init_security; + struct hlist_head inode_init_security_anon; struct hlist_head inode_create; struct hlist_head inode_link; struct hlist_head inode_unlink; diff --git a/include/linux/security.h b/include/linux/security.h index 66c49a244fd7..a8c99a229795 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -320,6 +320,9 @@ void security_inode_free(struct inode *inode); int security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, initxattrs initxattrs, void *fs_data); +int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode); int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len); @@ -724,6 +727,13 @@ static inline int security_inode_init_security(struct inode *inode, return 0; } +static inline int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + return 0; +} + static inline int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, diff --git a/security/security.c b/security/security.c index 96c26192d84c..fa2982105e4c 100644 --- a/security/security.c +++ b/security/security.c @@ -1014,6 +1014,14 @@ out: } EXPORT_SYMBOL(security_inode_init_security); +int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + return call_int_hook(inode_init_security_anon, 0, inode, name, + context_inode); +} + int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len)