[PATCH 2/2] audit signal recipients (v3)
Amy Griffis
amy.griffis at hp.com
Thu Mar 29 22:01:04 UTC 2007
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 at hp.com>
---
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
More information about the Linux-audit
mailing list