From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f67.google.com ([209.85.160.67]:41552 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753099AbeGBSpr (ORCPT ); Mon, 2 Jul 2018 14:45:47 -0400 Subject: Re: [PATCH v5 1/8] security: define new LSM hook named security_kernel_load_data To: Mimi Zohar , linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, David Howells , "Luis R . Rodriguez" , Eric Biederman , kexec@lists.infradead.org, Andres Rodriguez , Greg Kroah-Hartman , Ard Biesheuvel , Kees Cook , Casey Schaufler References: <1530542283-26145-1-git-send-email-zohar@linux.vnet.ibm.com> <1530542283-26145-2-git-send-email-zohar@linux.vnet.ibm.com> From: J Freyensee Message-ID: <64f467a5-e907-ee3e-495b-b2c731715037@gmail.com> Date: Mon, 2 Jul 2018 11:45:44 -0700 MIME-Version: 1.0 In-Reply-To: <1530542283-26145-2-git-send-email-zohar@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-integrity-owner@vger.kernel.org List-ID: On 7/2/18 7:37 AM, Mimi Zohar wrote: > Differentiate between the kernel reading a file from the kernel loading > data provided by userspace. This patch defines a new LSM hook named > security_kernel_load_data. If this patch series is re-done, can we tweak the description here please? From what I understood of the code in this patch, I'd tweak it as: "Differentiate between the kernel reading a file specified by userspace and the kernel loading a block of data provided by userspace. This patch defines a new LSM hook named security_kernel_load_data()." From the description, I got a tad confused if the the kernel reading a file was also provided by userspace (I know it may be 2nd-nature to people on this list, I'm still learning this kernel module). Thanks, Jay > Signed-off-by: Mimi Zohar > Cc: Eric Biederman > Cc: Luis R. Rodriguez > Cc: Kees Cook > Cc: David Howells > Cc: Casey Schaufler > Acked-by: Serge Hallyn > > --- > Changelog v5: > - Share the kernel_load_data_id and kernel_read_file_id values, > simplifying Loadpin's and other LSMs calling one LSM hook from the > other. > > Changelog v4: > - Define new LSM hook named security_kernel_load_data. > > Changelog v3: > - Rename security_kernel_read_file to security_kernel_read_data(). > > Changelog v2: > - Define a generic wrapper named security_kernel_read_blob() for > security_kernel_read_file(). > > Changelog v1: > - Define and call security_kexec_load(), a wrapper for > security_kernel_read_file(). > > include/linux/lsm_hooks.h | 6 ++++++ > include/linux/security.h | 27 +++++++++++++++++++++++++++ > security/security.c | 5 +++++ > 3 files changed, 38 insertions(+) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index 8f1131c8dd54..a08bc2587b96 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -576,6 +576,10 @@ > * userspace to load a kernel module with the given name. > * @kmod_name name of the module requested by the kernel > * Return 0 if successful. > + * @kernel_load_data: > + * Load data provided by userspace. > + * @id kernel load data identifier > + * Return 0 if permission is granted. > * @kernel_read_file: > * Read a file specified by userspace. > * @file contains the file structure pointing to the file being read > @@ -1582,6 +1586,7 @@ union security_list_options { > int (*kernel_act_as)(struct cred *new, u32 secid); > int (*kernel_create_files_as)(struct cred *new, struct inode *inode); > int (*kernel_module_request)(char *kmod_name); > + int (*kernel_load_data)(enum kernel_load_data_id id); > int (*kernel_read_file)(struct file *file, enum kernel_read_file_id id); > int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size, > enum kernel_read_file_id id); > @@ -1872,6 +1877,7 @@ struct security_hook_heads { > struct hlist_head cred_getsecid; > struct hlist_head kernel_act_as; > struct hlist_head kernel_create_files_as; > + struct hlist_head kernel_load_data; > struct hlist_head kernel_read_file; > struct hlist_head kernel_post_read_file; > struct hlist_head kernel_module_request; > diff --git a/include/linux/security.h b/include/linux/security.h > index 63030c85ee19..3410acfe139c 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -159,6 +159,27 @@ extern int mmap_min_addr_handler(struct ctl_table *table, int write, > typedef int (*initxattrs) (struct inode *inode, > const struct xattr *xattr_array, void *fs_data); > > + > +/* Keep the kernel_load_data_id enum in sync with kernel_read_file_id */ > +#define __data_id_enumify(ENUM, dummy) LOADING_ ## ENUM, > +#define __data_id_stringify(dummy, str) #str, > + > +enum kernel_load_data_id { > + __kernel_read_file_id(__data_id_enumify) > +}; > + > +static const char * const kernel_load_data_str[] = { > + __kernel_read_file_id(__data_id_stringify) > +}; > + > +static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id) > +{ > + if ((unsigned)id >= LOADING_MAX_ID) > + return kernel_load_data_str[LOADING_UNKNOWN]; > + > + return kernel_load_data_str[id]; > +} > + > #ifdef CONFIG_SECURITY > > struct security_mnt_opts { > @@ -320,6 +341,7 @@ void security_cred_getsecid(const struct cred *c, u32 *secid); > int security_kernel_act_as(struct cred *new, u32 secid); > int security_kernel_create_files_as(struct cred *new, struct inode *inode); > int security_kernel_module_request(char *kmod_name); > +int security_kernel_load_data(enum kernel_load_data_id id); > int security_kernel_read_file(struct file *file, enum kernel_read_file_id id); > int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, > enum kernel_read_file_id id); > @@ -909,6 +931,11 @@ static inline int security_kernel_module_request(char *kmod_name) > return 0; > } > > +static inline int security_kernel_load_data(enum kernel_load_data_id id) > +{ > + return 0; > +} > + > static inline int security_kernel_read_file(struct file *file, > enum kernel_read_file_id id) > { > diff --git a/security/security.c b/security/security.c > index e7d76a8000a5..05fe5b1932d7 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1061,6 +1061,11 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, > } > EXPORT_SYMBOL_GPL(security_kernel_post_read_file); > > +int security_kernel_load_data(enum kernel_load_data_id id) > +{ > + return call_int_hook(kernel_load_data, 0, id); > +} > + > int security_task_fix_setuid(struct cred *new, const struct cred *old, > int flags) > {