| Message ID | 1530542283-26145-2-git-send-email-zohar@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <zohar@linux.vnet.ibm.com> > Cc: Eric Biederman <ebiederm@xmission.com> > Cc: Luis R. Rodriguez <mcgrof@kernel.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: David Howells <dhowells@redhat.com> > Cc: Casey Schaufler <casey@schaufler-ca.com> > Acked-by: Serge Hallyn <serge@hallyn.com> > > --- > 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) > {
On Mon, 2018-07-02 at 11:45 -0700, J Freyensee wrote: > > 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). Could we replace "a block of data provided by userspace" with just "data provided by userspace"? Mimi
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) {