From 89eda06837094ce9f34fae269b8773fcfd70f046 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sun, 4 Oct 2009 21:49:47 +0900 Subject: LSM: Add security_path_chmod() and security_path_chown(). This patch allows pathname based LSM modules to check chmod()/chown() operations. Since notify_change() does not receive "struct vfsmount *", we add security_path_chmod() and security_path_chown() to the caller of notify_change(). These hooks are used by TOMOYO. Signed-off-by: Tetsuo Handa Signed-off-by: James Morris --- include/linux/security.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'include/linux/security.h') diff --git a/include/linux/security.h b/include/linux/security.h index 239e40d0450..c8a584c26f7 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -447,6 +447,18 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @new_dir contains the path structure for parent of the new link. * @new_dentry contains the dentry structure of the new link. * Return 0 if permission is granted. + * @path_chmod: + * Check for permission to change DAC's permission of a file or directory. + * @dentry contains the dentry structure. + * @mnt contains the vfsmnt structure. + * @mode contains DAC's mode. + * Return 0 if permission is granted. + * @path_chown: + * Check for permission to change owner/group of a file or directory. + * @path contains the path structure. + * @uid contains new owner's ID. + * @gid contains new group's ID. + * Return 0 if permission is granted. * @inode_readlink: * Check the permission to read the symbolic link. * @dentry contains the dentry structure for the file link. @@ -1488,6 +1500,9 @@ struct security_operations { struct dentry *new_dentry); int (*path_rename) (struct path *old_dir, struct dentry *old_dentry, struct path *new_dir, struct dentry *new_dentry); + int (*path_chmod) (struct dentry *dentry, struct vfsmount *mnt, + mode_t mode); + int (*path_chown) (struct path *path, uid_t uid, gid_t gid); #endif int (*inode_alloc_security) (struct inode *inode); @@ -2952,6 +2967,9 @@ int security_path_link(struct dentry *old_dentry, struct path *new_dir, struct dentry *new_dentry); int security_path_rename(struct path *old_dir, struct dentry *old_dentry, struct path *new_dir, struct dentry *new_dentry); +int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt, + mode_t mode); +int security_path_chown(struct path *path, uid_t uid, gid_t gid); #else /* CONFIG_SECURITY_PATH */ static inline int security_path_unlink(struct path *dir, struct dentry *dentry) { @@ -3001,6 +3019,18 @@ static inline int security_path_rename(struct path *old_dir, { return 0; } + +static inline int security_path_chmod(struct dentry *dentry, + struct vfsmount *mnt, + mode_t mode) +{ + return 0; +} + +static inline int security_path_chown(struct path *path, uid_t uid, gid_t gid) +{ + return 0; +} #endif /* CONFIG_SECURITY_PATH */ #ifdef CONFIG_KEYS -- cgit v1.2.3-70-g09d2 From 8b8efb44033c7e86b3dc76f825c693ec92ae30e9 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sun, 4 Oct 2009 21:49:48 +0900 Subject: LSM: Add security_path_chroot(). This patch allows pathname based LSM modules to check chroot() operations. This hook is used by TOMOYO. Signed-off-by: Tetsuo Handa Signed-off-by: James Morris --- fs/open.c | 3 +++ include/linux/security.h | 11 +++++++++++ security/capability.c | 6 ++++++ security/security.c | 5 +++++ 4 files changed, 25 insertions(+) (limited to 'include/linux/security.h') diff --git a/fs/open.c b/fs/open.c index b5c294d35bd..201041dfca5 100644 --- a/fs/open.c +++ b/fs/open.c @@ -587,6 +587,9 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename) error = -EPERM; if (!capable(CAP_SYS_CHROOT)) goto dput_and_out; + error = security_path_chroot(&path); + if (error) + goto dput_and_out; set_fs_root(current->fs, &path); error = 0; diff --git a/include/linux/security.h b/include/linux/security.h index c8a584c26f7..ed0faea60b8 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -459,6 +459,10 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @uid contains new owner's ID. * @gid contains new group's ID. * Return 0 if permission is granted. + * @path_chroot: + * Check for permission to change root directory. + * @path contains the path structure. + * Return 0 if permission is granted. * @inode_readlink: * Check the permission to read the symbolic link. * @dentry contains the dentry structure for the file link. @@ -1503,6 +1507,7 @@ struct security_operations { int (*path_chmod) (struct dentry *dentry, struct vfsmount *mnt, mode_t mode); int (*path_chown) (struct path *path, uid_t uid, gid_t gid); + int (*path_chroot) (struct path *path); #endif int (*inode_alloc_security) (struct inode *inode); @@ -2970,6 +2975,7 @@ int security_path_rename(struct path *old_dir, struct dentry *old_dentry, int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt, mode_t mode); int security_path_chown(struct path *path, uid_t uid, gid_t gid); +int security_path_chroot(struct path *path); #else /* CONFIG_SECURITY_PATH */ static inline int security_path_unlink(struct path *dir, struct dentry *dentry) { @@ -3031,6 +3037,11 @@ static inline int security_path_chown(struct path *path, uid_t uid, gid_t gid) { return 0; } + +static inline int security_path_chroot(struct path *path) +{ + return 0; +} #endif /* CONFIG_SECURITY_PATH */ #ifdef CONFIG_KEYS diff --git a/security/capability.c b/security/capability.c index 09279a8d4a1..4f3ab476937 100644 --- a/security/capability.c +++ b/security/capability.c @@ -319,6 +319,11 @@ static int cap_path_chown(struct path *path, uid_t uid, gid_t gid) { return 0; } + +static int cap_path_chroot(struct path *root) +{ + return 0; +} #endif static int cap_file_permission(struct file *file, int mask) @@ -990,6 +995,7 @@ void security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, path_truncate); set_to_cap_if_null(ops, path_chmod); set_to_cap_if_null(ops, path_chown); + set_to_cap_if_null(ops, path_chroot); #endif set_to_cap_if_null(ops, file_permission); set_to_cap_if_null(ops, file_alloc_security); diff --git a/security/security.c b/security/security.c index 5259270e558..279757314a0 100644 --- a/security/security.c +++ b/security/security.c @@ -449,6 +449,11 @@ int security_path_chown(struct path *path, uid_t uid, gid_t gid) return 0; return security_ops->path_chown(path, uid, gid); } + +int security_path_chroot(struct path *path) +{ + return security_ops->path_chroot(path); +} #endif int security_inode_create(struct inode *dir, struct dentry *dentry, int mode) -- cgit v1.2.3-70-g09d2 From dd8dbf2e6880e30c00b18600c962d0cb5a03c555 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Nov 2009 16:35:32 +1100 Subject: security: report the module name to security_module_request For SELinux to do better filtering in userspace we send the name of the module along with the AVC denial when a program is denied module_request. Example output: type=SYSCALL msg=audit(11/03/2009 10:59:43.510:9) : arch=x86_64 syscall=write success=yes exit=2 a0=3 a1=7fc28c0d56c0 a2=2 a3=7fffca0d7440 items=0 ppid=1727 pid=1729 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.nfsd exe=/usr/sbin/rpc.nfsd subj=system_u:system_r:nfsd_t:s0 key=(null) type=AVC msg=audit(11/03/2009 10:59:43.510:9) : avc: denied { module_request } for pid=1729 comm=rpc.nfsd kmod="net-pf-10" scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system Signed-off-by: Eric Paris Signed-off-by: James Morris --- include/linux/lsm_audit.h | 18 ++++++++++-------- include/linux/security.h | 7 ++++--- kernel/kmod.c | 8 ++++---- security/capability.c | 2 +- security/lsm_audit.c | 4 ++++ security/security.c | 4 ++-- security/selinux/hooks.c | 13 +++++++++++-- 7 files changed, 36 insertions(+), 20 deletions(-) (limited to 'include/linux/security.h') diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h index 190c3785487..f78f83d7663 100644 --- a/include/linux/lsm_audit.h +++ b/include/linux/lsm_audit.h @@ -26,14 +26,15 @@ /* Auxiliary data to use in generating the audit record. */ struct common_audit_data { - char type; -#define LSM_AUDIT_DATA_FS 1 -#define LSM_AUDIT_DATA_NET 2 -#define LSM_AUDIT_DATA_CAP 3 -#define LSM_AUDIT_DATA_IPC 4 -#define LSM_AUDIT_DATA_TASK 5 -#define LSM_AUDIT_DATA_KEY 6 -#define LSM_AUDIT_NO_AUDIT 7 + char type; +#define LSM_AUDIT_DATA_FS 1 +#define LSM_AUDIT_DATA_NET 2 +#define LSM_AUDIT_DATA_CAP 3 +#define LSM_AUDIT_DATA_IPC 4 +#define LSM_AUDIT_DATA_TASK 5 +#define LSM_AUDIT_DATA_KEY 6 +#define LSM_AUDIT_NO_AUDIT 7 +#define LSM_AUDIT_DATA_KMOD 8 struct task_struct *tsk; union { struct { @@ -66,6 +67,7 @@ struct common_audit_data { char *key_desc; } key_struct; #endif + char *kmod_name; } u; /* this union contains LSM specific data */ union { diff --git a/include/linux/security.h b/include/linux/security.h index ed0faea60b8..466cbadbd1e 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -706,6 +706,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @kernel_module_request: * Ability to trigger the kernel to automatically upcall to userspace for * userspace to load a kernel module with the given name. + * @kmod_name name of the module requested by the kernel * Return 0 if successful. * @task_setuid: * Check permission before setting one or more of the user identity @@ -1577,7 +1578,7 @@ struct security_operations { void (*cred_transfer)(struct cred *new, const struct cred *old); int (*kernel_act_as)(struct cred *new, u32 secid); int (*kernel_create_files_as)(struct cred *new, struct inode *inode); - int (*kernel_module_request)(void); + int (*kernel_module_request)(char *kmod_name); int (*task_setuid) (uid_t id0, uid_t id1, uid_t id2, int flags); int (*task_fix_setuid) (struct cred *new, const struct cred *old, int flags); @@ -1842,7 +1843,7 @@ void security_commit_creds(struct cred *new, const struct cred *old); void security_transfer_creds(struct cred *new, const struct cred *old); 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(void); +int security_kernel_module_request(char *kmod_name); int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags); int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags); @@ -2407,7 +2408,7 @@ static inline int security_kernel_create_files_as(struct cred *cred, return 0; } -static inline int security_kernel_module_request(void) +static inline int security_kernel_module_request(char *kmod_name) { return 0; } diff --git a/kernel/kmod.c b/kernel/kmod.c index 9fcb53a11f8..25b10319036 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -80,16 +80,16 @@ int __request_module(bool wait, const char *fmt, ...) #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; - ret = security_kernel_module_request(); - if (ret) - return ret; - va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; + ret = security_kernel_module_request(module_name); + if (ret) + return ret; + /* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method diff --git a/security/capability.c b/security/capability.c index 4f3ab476937..5c700e1a4fd 100644 --- a/security/capability.c +++ b/security/capability.c @@ -421,7 +421,7 @@ static int cap_kernel_create_files_as(struct cred *new, struct inode *inode) return 0; } -static int cap_kernel_module_request(void) +static int cap_kernel_module_request(char *kmod_name) { return 0; } diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 3bb90b6f1dd..51bd0fd9c9f 100644 --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -354,6 +354,10 @@ static void dump_common_audit_data(struct audit_buffer *ab, } break; #endif + case LSM_AUDIT_DATA_KMOD: + audit_log_format(ab, " kmod="); + audit_log_untrustedstring(ab, a->u.kmod_name); + break; } /* switch (a->type) */ } diff --git a/security/security.c b/security/security.c index aad71b2ca19..24e060be9fa 100644 --- a/security/security.c +++ b/security/security.c @@ -764,9 +764,9 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode) return security_ops->kernel_create_files_as(new, inode); } -int security_kernel_module_request(void) +int security_kernel_module_request(char *kmod_name) { - return security_ops->kernel_module_request(); + return security_ops->kernel_module_request(kmod_name); } int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a29d6612a32..c96d63ec475 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3337,9 +3337,18 @@ static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode) return 0; } -static int selinux_kernel_module_request(void) +static int selinux_kernel_module_request(char *kmod_name) { - return task_has_system(current, SYSTEM__MODULE_REQUEST); + u32 sid; + struct common_audit_data ad; + + sid = task_sid(current); + + COMMON_AUDIT_DATA_INIT(&ad, KMOD); + ad.u.kmod_name = kmod_name; + + return avc_has_perm(sid, SECINITSID_KERNEL, SECCLASS_SYSTEM, + SYSTEM__MODULE_REQUEST, &ad); } static int selinux_task_setpgid(struct task_struct *p, pid_t pgid) -- cgit v1.2.3-70-g09d2 From 6e1415467614e854fee660ff6648bd10fa976e95 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 15 Dec 2009 19:27:45 +0000 Subject: NOMMU: Optimise away the {dac_,}mmap_min_addr tests In NOMMU mode clamp dac_mmap_min_addr to zero to cause the tests on it to be skipped by the compiler. We do this as the minimum mmap address doesn't make any sense in NOMMU mode. mmap_min_addr and round_hint_to_min() can be discarded entirely in NOMMU mode. Signed-off-by: David Howells Acked-by: Eric Paris Signed-off-by: James Morris --- include/linux/security.h | 7 +++++++ kernel/sysctl.c | 2 ++ mm/Kconfig | 1 + security/Makefile | 3 ++- 4 files changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux/security.h') diff --git a/include/linux/security.h b/include/linux/security.h index 466cbadbd1e..2c627d361c0 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -95,8 +95,13 @@ struct seq_file; extern int cap_netlink_send(struct sock *sk, struct sk_buff *skb); extern int cap_netlink_recv(struct sk_buff *skb, int cap); +#ifdef CONFIG_MMU extern unsigned long mmap_min_addr; extern unsigned long dac_mmap_min_addr; +#else +#define dac_mmap_min_addr 0UL +#endif + /* * Values used in the task_security_ops calls */ @@ -121,6 +126,7 @@ struct request_sock; #define LSM_UNSAFE_PTRACE 2 #define LSM_UNSAFE_PTRACE_CAP 4 +#ifdef CONFIG_MMU /* * If a hint addr is less than mmap_min_addr change hint to be as * low as possible but still greater than mmap_min_addr @@ -135,6 +141,7 @@ static inline unsigned long round_hint_to_min(unsigned long hint) } extern int mmap_min_addr_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +#endif #ifdef CONFIG_SECURITY diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 45e4bef0012..856a24eadf7 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1214,6 +1214,7 @@ static struct ctl_table vm_table[] = { .proc_handler = proc_dointvec_jiffies, }, #endif +#ifdef CONFIG_MMU { .procname = "mmap_min_addr", .data = &dac_mmap_min_addr, @@ -1221,6 +1222,7 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = mmap_min_addr_handler, }, +#endif #ifdef CONFIG_NUMA { .procname = "numa_zonelist_order", diff --git a/mm/Kconfig b/mm/Kconfig index 43ea8c3a2bb..ee9f3e0f2b6 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -221,6 +221,7 @@ config KSM config DEFAULT_MMAP_MIN_ADDR int "Low address space to protect from user allocation" + depends on MMU default 4096 help This is the portion of low virtual memory which should be protected diff --git a/security/Makefile b/security/Makefile index bb44e350c61..da20a193c8d 100644 --- a/security/Makefile +++ b/security/Makefile @@ -8,7 +8,8 @@ subdir-$(CONFIG_SECURITY_SMACK) += smack subdir-$(CONFIG_SECURITY_TOMOYO) += tomoyo # always enable default capabilities -obj-y += commoncap.o min_addr.o +obj-y += commoncap.o +obj-$(CONFIG_MMU) += min_addr.o # Object file lists obj-$(CONFIG_SECURITY) += security.o capability.o -- cgit v1.2.3-70-g09d2