diff options
| -rw-r--r-- | include/linux/lsm_hooks.h | 52 | ||||
| -rw-r--r-- | security/security.c | 69 |
2 files changed, 69 insertions, 52 deletions
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 6e156d2acffc..784e19fd665b 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -32,58 +32,6 @@ /** * union security_list_options - Linux Security Module hook function list * - * Security hooks for program execution operations. - * - * @bprm_creds_for_exec: - * If the setup in prepare_exec_creds did not setup @bprm->cred->security - * properly for executing @bprm->file, update the LSM's portion of - * @bprm->cred->security to be what commit_creds needs to install for the - * new program. This hook may also optionally check permissions - * (e.g. for transitions between security domains). - * The hook must set @bprm->secureexec to 1 if AT_SECURE should be set to - * request libc enable secure mode. - * @bprm contains the linux_binprm structure. - * Return 0 if the hook is successful and permission is granted. - * @bprm_creds_from_file: - * If @file is setpcap, suid, sgid or otherwise marked to change - * privilege upon exec, update @bprm->cred to reflect that change. - * This is called after finding the binary that will be executed. - * without an interpreter. This ensures that the credentials will not - * be derived from a script that the binary will need to reopen, which - * when reopend may end up being a completely different file. This - * hook may also optionally check permissions (e.g. for transitions - * between security domains). - * The hook must set @bprm->secureexec to 1 if AT_SECURE should be set to - * request libc enable secure mode. - * The hook must add to @bprm->per_clear any personality flags that - * should be cleared from current->personality. - * @bprm contains the linux_binprm structure. - * Return 0 if the hook is successful and permission is granted. - * @bprm_check_security: - * This hook mediates the point when a search for a binary handler will - * begin. It allows a check against the @bprm->cred->security value - * which was set in the preceding creds_for_exec call. The argv list and - * envp list are reliably available in @bprm. This hook may be called - * multiple times during a single execve. - * @bprm contains the linux_binprm structure. - * Return 0 if the hook is successful and permission is granted. - * @bprm_committing_creds: - * Prepare to install the new security attributes of a process being - * transformed by an execve operation, based on the old credentials - * pointed to by @current->cred and the information set in @bprm->cred by - * the bprm_creds_for_exec hook. @bprm points to the linux_binprm - * structure. This hook is a good place to perform state changes on the - * process such as closing open file descriptors to which access will no - * longer be granted when the attributes are changed. This is called - * immediately before commit_creds(). - * @bprm_committed_creds: - * Tidy up after the installation of the new security attributes of a - * process being transformed by an execve operation. The new credentials - * have, by this point, been set to @current->cred. @bprm points to the - * linux_binprm structure. This hook is a good place to perform state - * changes on the process such as clearing out non-inheritable signal - * state. This is called immediately after commit_creds(). - * * Security hooks for mount using fs_context. * [See also Documentation/filesystems/mount_api.rst] * diff --git a/security/security.c b/security/security.c index cf6cc576736f..1e7dbaf9ad28 100644 --- a/security/security.c +++ b/security/security.c @@ -6,6 +6,7 @@ * Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com> * Copyright (C) 2001 Networks Associates Technology, Inc <ssmalley@nai.com> * Copyright (C) 2016 Mellanox Technologies + * Copyright (C) 2023 Microsoft Corporation <paul@paul-moore.com> */ #define pr_fmt(fmt) "LSM: " fmt @@ -880,16 +881,61 @@ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages) return __vm_enough_memory(mm, pages, cap_sys_admin); } +/** + * security_bprm_creds_for_exec() - Prepare the credentials for exec() + * @bprm: binary program information + * + * If the setup in prepare_exec_creds did not setup @bprm->cred->security + * properly for executing @bprm->file, update the LSM's portion of + * @bprm->cred->security to be what commit_creds needs to install for the new + * program. This hook may also optionally check permissions (e.g. for + * transitions between security domains). The hook must set @bprm->secureexec + * to 1 if AT_SECURE should be set to request libc enable secure mode. @bprm + * contains the linux_binprm structure. + * + * Return: Returns 0 if the hook is successful and permission is granted. + */ int security_bprm_creds_for_exec(struct linux_binprm *bprm) { return call_int_hook(bprm_creds_for_exec, 0, bprm); } +/** + * security_bprm_creds_from_file() - Update linux_binprm creds based on file + * @bprm: binary program information + * @file: associated file + * + * If @file is setpcap, suid, sgid or otherwise marked to change privilege upon + * exec, update @bprm->cred to reflect that change. This is called after + * finding the binary that will be executed without an interpreter. This + * ensures that the credentials will not be derived from a script that the + * binary will need to reopen, which when reopend may end up being a completely + * different file. This hook may also optionally check permissions (e.g. for + * transitions between security domains). The hook must set @bprm->secureexec + * to 1 if AT_SECURE should be set to request libc enable secure mode. The + * hook must add to @bprm->per_clear any personality flags that should be + * cleared from current->personality. @bprm contains the linux_binprm + * structure. + * + * Return: Returns 0 if the hook is successful and permission is granted. + */ int security_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file) { return call_int_hook(bprm_creds_from_file, 0, bprm, file); } +/** + * security_bprm_check() - Mediate binary handler search + * @bprm: binary program information + * + * This hook mediates the point when a search for a binary handler will begin. + * It allows a check against the @bprm->cred->security value which was set in + * the preceding creds_for_exec call. The argv list and envp list are reliably + * available in @bprm. This hook may be called multiple times during a single + * execve. @bprm contains the linux_binprm structure. + * + * Return: Returns 0 if the hook is successful and permission is granted. + */ int security_bprm_check(struct linux_binprm *bprm) { int ret; @@ -900,11 +946,34 @@ int security_bprm_check(struct linux_binprm *bprm) return ima_bprm_check(bprm); } +/** + * security_bprm_committing_creds() - Install creds for a process during exec() + * @bprm: binary program information + * + * Prepare to install the new security attributes of a process being + * transformed by an execve operation, based on the old credentials pointed to + * by @current->cred and the information set in @bprm->cred by the + * bprm_creds_for_exec hook. @bprm points to the linux_binprm structure. This + * hook is a good place to perform state changes on the process such as closing + * open file descriptors to which access will no longer be granted when the + * attributes are changed. This is called immediately before commit_creds(). + */ void security_bprm_committing_creds(struct linux_binprm *bprm) { call_void_hook(bprm_committing_creds, bprm); } +/** + * security_bprm_committed_creds() - Tidy up after cred install during exec() + * @bprm: binary program information + * + * Tidy up after the installation of the new security attributes of a process + * being transformed by an execve operation. The new credentials have, by this + * point, been set to @current->cred. @bprm points to the linux_binprm + * structure. This hook is a good place to perform state changes on the + * process such as clearing out non-inheritable signal state. This is called + * immediately after commit_creds(). + */ void security_bprm_committed_creds(struct linux_binprm *bprm) { call_void_hook(bprm_committed_creds, bprm); |