When auditing syscalls that send signals, log the pid and security context for each target process. Optimize the data collection by adding a counter for signal-related rules, and avoiding allocating an aux struct unless we have more than one target process. For process groups, collect pid/context data in blocks of 16. Move the audit_signal_info() hook up in check_kill_permission() so we audit attempts where permission is denied. Signed-off-by: Amy Griffis <amy.griffis(a)hp.com&gt; --- arch/ia64/kernel/audit.c | 9 +++ arch/powerpc/kernel/audit.c | 9 +++ arch/s390/kernel/audit.c | 9 +++ arch/sparc64/kernel/audit.c | 9 +++ arch/x86_64/kernel/audit.c | 9 +++ include/linux/audit.h | 3 + kernel/audit.h | 13 +++-- kernel/auditfilter.c | 48 +++++++++++++++++- kernel/auditsc.c | 116 ++++++++++++++++++++++++++++++++++-------- kernel/signal.c | 10 ++-- lib/audit.c | 5 ++ 11 files changed, 208 insertions(+), 32 deletions(-) diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c index 538312a..f3802ae 100644 --- a/arch/ia64/kernel/audit.c +++ b/arch/ia64/kernel/audit.c @@ -28,6 +28,15 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ +#ifdef CONFIG_IA32_SUPPORT + if (arch == AUDIT_ARCH_I386) + return 1; +#endif + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { #ifdef CONFIG_IA32_SUPPORT diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c index 66d54ba..a4dab7c 100644 --- a/arch/powerpc/kernel/audit.c +++ b/arch/powerpc/kernel/audit.c @@ -28,6 +28,15 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ +#ifdef CONFIG_PPC64 + if (arch == AUDIT_ARCH_PPC) + return 1; +#endif + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { #ifdef CONFIG_PPC64 diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c index 7affafe..d1c76fe 100644 --- a/arch/s390/kernel/audit.c +++ b/arch/s390/kernel/audit.c @@ -28,6 +28,15 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ +#ifdef CONFIG_COMPAT + if (arch == AUDIT_ARCH_S390) + return 1; +#endif + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { #ifdef CONFIG_COMPAT diff --git a/arch/sparc64/kernel/audit.c b/arch/sparc64/kernel/audit.c index d57a9da..24d7f4b 100644 --- a/arch/sparc64/kernel/audit.c +++ b/arch/sparc64/kernel/audit.c @@ -28,6 +28,15 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ +#ifdef CONFIG_SPARC32_COMPAT + if (arch == AUDIT_ARCH_SPARC) + return 1; +#endif + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { #ifdef CONFIG_SPARC32_COMPAT diff --git a/arch/x86_64/kernel/audit.c b/arch/x86_64/kernel/audit.c index b970de6..06d3e5a 100644 --- a/arch/x86_64/kernel/audit.c +++ b/arch/x86_64/kernel/audit.c @@ -28,6 +28,15 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ +#ifdef CONFIG_IA32_EMULATION + if (arch == AUDIT_ARCH_I386) + return 1; +#endif + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { #ifdef CONFIG_IA32_EMULATION diff --git a/include/linux/audit.h b/include/linux/audit.h index e4bd622..ac84347 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -344,6 +344,7 @@ struct mqstat; #define AUDITSC_RESULT(x) ( ((long)(x))<0?AUDITSC_FAILURE:AUDITSC_SUCCESS ) extern int __init audit_register_class(int class, unsigned *list); extern int audit_classify_syscall(int abi, unsigned syscall); +extern int audit_classify_arch(int arch); #ifdef CONFIG_AUDITSYSCALL /* These are defined in auditsc.c */ /* Public API */ @@ -456,6 +457,7 @@ static inline int audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat) return 0; } extern int audit_n_rules; +extern int audit_signals; #else #define audit_alloc(t) ({ 0; }) #define audit_free(t) do { ; } while (0) @@ -486,6 +488,7 @@ extern int audit_n_rules; #define audit_mq_getsetattr(d,s) ({ 0; }) #define audit_ptrace(t) ((void)0) #define audit_n_rules 0 +#define audit_signals 0 #endif #ifdef CONFIG_AUDIT diff --git a/kernel/audit.h b/kernel/audit.h index a337023..815d6f5 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -83,6 +83,7 @@ struct audit_krule { u32 field_count; char *filterkey; /* ties events to rules */ struct audit_field *fields; + struct audit_field *arch_f; /* quick access to arch field */ struct audit_field *inode_f; /* quick access to an inode field */ struct audit_watch *watch; /* associated watch */ struct list_head rlist; /* entry in audit_watch.rules list */ @@ -131,17 +132,19 @@ extern void audit_handle_ievent(struct inotify_watch *, u32, u32, u32, extern int selinux_audit_rule_update(void); #ifdef CONFIG_AUDITSYSCALL -extern void __audit_signal_info(int sig, struct task_struct *t); -static inline void audit_signal_info(int sig, struct task_struct *t) +extern int __audit_signal_info(int sig, struct task_struct *t); +static inline int audit_signal_info(int sig, struct task_struct *t) { - if (unlikely(audit_pid && t->tgid == audit_pid)) - __audit_signal_info(sig, t); + if (unlikely((audit_pid && t->tgid == audit_pid) || + (audit_signals && !audit_dummy_context()))) + return __audit_signal_info(sig, t); + return 0; } extern enum audit_state audit_filter_inodes(struct task_struct *, struct audit_context *); extern void audit_set_auditable(struct audit_context *); #else -#define audit_signal_info(s,t) +#define audit_signal_info(s,t) AUDIT_DISABLED #define audit_filter_inodes(t,c) AUDIT_DISABLED #define audit_set_auditable(c) #endif diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index 2ddd154..76c9291 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -313,6 +313,43 @@ int audit_match_class(int class, unsigned syscall) return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall); } +static inline int audit_match_class_bits(int class, u32 *mask) +{ + int i; + + if (classes[class]) { + for (i = 0; i < AUDIT_BITMASK_SIZE; i++) + if (mask[i] & classes[class][i]) + return 0; + } + return 1; +} + +static int audit_match_signal(struct audit_entry *entry) +{ + struct audit_field *arch = entry->rule.arch_f; + + if (!arch) { + /* When arch is unspecified, we must check both masks on biarch + * as syscall number alone is ambiguous. */ + return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, + entry->rule.mask) && + audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, + entry->rule.mask)); + } + + switch(audit_classify_arch(arch->val)) { + case 0: /* native */ + return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, + entry->rule.mask)); + case 1: /* 32bit on biarch */ + return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, + entry->rule.mask)); + default: + return 1; + } +} + /* Common user-space to kernel rule translation. */ static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) { @@ -438,6 +475,7 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) err = -EINVAL; goto exit_free; } + entry->rule.arch_f = f; break; case AUDIT_PERM: if (f->val & ~15) @@ -528,7 +566,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, case AUDIT_FSGID: case AUDIT_LOGINUID: case AUDIT_PERS: - case AUDIT_ARCH: case AUDIT_MSGTYPE: case AUDIT_PPID: case AUDIT_DEVMAJOR: @@ -540,6 +577,9 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, case AUDIT_ARG2: case AUDIT_ARG3: break; + case AUDIT_ARCH: + entry->rule.arch_f = f; + break; case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: @@ -1237,6 +1277,9 @@ static inline int audit_add_rule(struct audit_entry *entry, #ifdef CONFIG_AUDITSYSCALL if (!dont_count) audit_n_rules++; + + if (!audit_match_signal(entry)) + audit_signals++; #endif mutex_unlock(&audit_filter_mutex); @@ -1310,6 +1353,9 @@ static inline int audit_del_rule(struct audit_entry *entry, #ifdef CONFIG_AUDITSYSCALL if (!dont_count) audit_n_rules--; + + if (!audit_match_signal(entry)) + audit_signals--; #endif mutex_unlock(&audit_filter_mutex); diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 64ff43b..2e0f79f 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -84,6 +84,9 @@ extern int audit_enabled; /* number of audit rules */ int audit_n_rules; +/* determines whether we collect data for signals sent */ +int audit_signals; + /* When fs/namei.c:getname() is called, we store the pointer in name and * we don't let putname() free it (instead we free all of the saved * pointers at syscall exit time). @@ -109,6 +112,9 @@ struct audit_aux_data { #define AUDIT_AUX_IPCPERM 0 +/* Number of target pids per aux struct. */ +#define AUDIT_AUX_PIDS 16 + struct audit_aux_data_mq_open { struct audit_aux_data d; int oflag; @@ -176,6 +182,13 @@ struct audit_aux_data_path { struct vfsmount *mnt; }; +struct audit_aux_data_pids { + struct audit_aux_data d; + pid_t target_pid[AUDIT_AUX_PIDS]; + u32 target_sid[AUDIT_AUX_PIDS]; + int pid_count; +}; + /* The per-task audit context. */ struct audit_context { int dummy; /* must be the first element */ @@ -196,6 +209,7 @@ struct audit_context { struct vfsmount * pwdmnt; struct audit_context *previous; /* For nested syscalls */ struct audit_aux_data *aux; + struct audit_aux_data *aux_pids; /* Save things to print about task_struct */ pid_t pid, ppid; @@ -205,7 +219,7 @@ struct audit_context { int arch; pid_t target_pid; - char * obj_ctx; + u32 target_sid; #if AUDIT_DEBUG int put_count; @@ -652,6 +666,10 @@ static inline void audit_free_aux(struct audit_context *context) context->aux = aux->next; kfree(aux); } + while ((aux = context->aux_pids)) { + context->aux_pids = aux->next; + kfree(aux); + } } static inline void audit_zero_context(struct audit_context *context, @@ -727,7 +745,6 @@ static inline void audit_free_context(struct audit_context *context) audit_free_names(context); audit_free_aux(context); kfree(context->filterkey); - kfree(context->obj_ctx); kfree(context); context = previous; } while (context); @@ -794,6 +811,29 @@ static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk audit_log_task_context(ab); } +static int audit_log_pid_context(struct audit_context *context, pid_t pid, + u32 sid) +{ + struct audit_buffer *ab; + char *s = NULL; + u32 len; + int rc = 0; + + ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID); + if (!ab) + return 1; + + if (selinux_sid_to_string(sid, &s, &len)) { + audit_log_format(ab, "opid=%d obj=(none)", pid); + rc = 1; + } else + audit_log_format(ab, "opid=%d obj=%s", pid, s); + audit_log_end(ab); + kfree(s); + + return rc; +} + static void audit_log_exit(struct audit_context *context, struct task_struct *tsk) { int i, call_panic = 0; @@ -972,16 +1012,21 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts audit_log_end(ab); } - if (context->target_pid) { - char *s = context->obj_ctx ? context->obj_ctx : "(none)"; - ab =audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID); - if (ab) { - audit_log_format(ab, "opid=%d obj=%s", - context->target_pid, s); - audit_log_end(ab); - } + for (aux = context->aux_pids; aux; aux = aux->next) { + struct audit_aux_data_pids *axs = (void *)aux; + int i; + + for (i = 0; i < axs->pid_count; i++) + if (audit_log_pid_context(context, axs->target_pid[i], + axs->target_sid[i])) + call_panic = 1; } + if (context->target_pid && + audit_log_pid_context(context, context->target_pid, + context->target_sid)) + call_panic = 1; + if (context->pwd && context->pwdmnt) { ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD); if (ab) { @@ -1202,9 +1247,10 @@ void audit_syscall_exit(int valid, long return_code) } else { audit_free_names(context); audit_free_aux(context); - kfree(context->obj_ctx); - context->obj_ctx = NULL; + context->aux = NULL; + context->aux_pids = NULL; context->target_pid = 0; + context->target_sid = 0; kfree(context->filterkey); context->filterkey = NULL; tsk->audit_context = context; @@ -1899,14 +1945,9 @@ int audit_sockaddr(int len, void *a) void __audit_ptrace(struct task_struct *t) { struct audit_context *context = current->audit_context; - unsigned len; - u32 sid; context->target_pid = t->pid; - - selinux_get_task_sid(t, &sid); - if (sid) - selinux_sid_to_string(sid, &context->obj_ctx, &len); + selinux_get_task_sid(t, &context->target_sid); } /** @@ -1947,15 +1988,17 @@ int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt) * If the audit subsystem is being terminated, record the task (pid) * and uid that is doing that. */ -void __audit_signal_info(int sig, struct task_struct *t) +int __audit_signal_info(int sig, struct task_struct *t) { + struct audit_aux_data_pids *axp; + struct task_struct *tsk = current; + struct audit_context *ctx = tsk->audit_context; extern pid_t audit_sig_pid; extern uid_t audit_sig_uid; extern u32 audit_sig_sid; - if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1) { - struct task_struct *tsk = current; - struct audit_context *ctx = tsk->audit_context; + if (audit_pid && t->tgid == audit_pid && + (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1)) { audit_sig_pid = tsk->pid; if (ctx) audit_sig_uid = ctx->loginuid; @@ -1963,4 +2006,33 @@ void __audit_signal_info(int sig, struct task_struct *t) audit_sig_uid = tsk->uid; selinux_get_task_sid(tsk, &audit_sig_sid); } + + if (!audit_signals) /* audit_context checked in wrapper */ + return 0; + + /* optimize the common case by putting first signal recipient directly + * in audit_context */ + if (!ctx->target_pid) { + ctx->target_pid = t->tgid; + selinux_get_task_sid(t, &ctx->target_sid); + return 0; + } + + axp = (void *)ctx->aux_pids; + if (!axp || axp->pid_count == AUDIT_AUX_PIDS) { + axp = kzalloc(sizeof(*axp), GFP_ATOMIC); + if (!axp) + return -ENOMEM; + + axp->d.type = AUDIT_OBJ_PID; + axp->d.next = ctx->aux_pids; + ctx->aux_pids = (void *)axp; + } + BUG_ON(axp->pid_count > AUDIT_AUX_PIDS); + + axp->target_pid[axp->pid_count] = t->tgid; + selinux_get_task_sid(t, &axp->target_sid[axp->pid_count]); + axp->pid_count++; + + return 0; } diff --git a/kernel/signal.c b/kernel/signal.c index 3670225..91d88eb 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -607,6 +607,11 @@ static int check_kill_permission(int sig, struct siginfo *info, int error = -EINVAL; if (!valid_signal(sig)) return error; + + error = audit_signal_info(sig, t); /* Let audit system see the signal */ + if (error) + return error; + error = -EPERM; if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) && ((sig != SIGCONT) || @@ -616,10 +621,7 @@ static int check_kill_permission(int sig, struct siginfo *info, && !capable(CAP_KILL)) return error; - error = security_task_kill(t, info, sig, 0); - if (!error) - audit_signal_info(sig, t); /* Let audit system see the signal */ - return error; + return security_task_kill(t, info, sig, 0); } /* forward decl */ diff --git a/lib/audit.c b/lib/audit.c index 50e9152..8e7dc1c 100644 --- a/lib/audit.c +++ b/lib/audit.c @@ -28,6 +28,11 @@ static unsigned signal_class[] = { ~0U }; +int audit_classify_arch(int arch) +{ + return 0; +} + int audit_classify_syscall(int abi, unsigned syscall) { switch(syscall) { -- 1.4.4.4