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(-) diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h index 190c37854870..f78f83d7663f 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 ed0faea60b82..466cbadbd1ef 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 9fcb53a11f87..25b103190364 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 4f3ab476937f..5c700e1a4fd3 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 3bb90b6f1dd3..51bd0fd9c9f0 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 aad71b2ca195..24e060be9fa5 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 a29d6612a328..c96d63ec4753 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 v1.2.2