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-rw-r--r--include/linux/seccomp.h11
-rw-r--r--include/uapi/linux/ptrace.h2
-rw-r--r--kernel/ptrace.c5
-rw-r--r--kernel/seccomp.c76
4 files changed, 93 insertions, 1 deletions
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index f426503..2296e6b 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -95,4 +95,15 @@ static inline void get_seccomp_filter(struct task_struct *tsk)
return;
}
#endif /* CONFIG_SECCOMP_FILTER */
+
+#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
+extern long seccomp_get_filter(struct task_struct *task,
+ unsigned long filter_off, void __user *data);
+#else
+static inline long seccomp_get_filter(struct task_struct *task,
+ unsigned long n, void __user *data)
+{
+ return -EINVAL;
+}
+#endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */
#endif /* _LINUX_SECCOMP_H */
diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h
index a7a6979..fb81065 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -64,6 +64,8 @@ struct ptrace_peeksiginfo_args {
#define PTRACE_GETSIGMASK 0x420a
#define PTRACE_SETSIGMASK 0x420b
+#define PTRACE_SECCOMP_GET_FILTER 0x420c
+
/* Read signals from a shared (process wide) queue */
#define PTRACE_PEEKSIGINFO_SHARED (1 << 0)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 787320d..b760bae 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1016,6 +1016,11 @@ int ptrace_request(struct task_struct *child, long request,
break;
}
#endif
+
+ case PTRACE_SECCOMP_GET_FILTER:
+ ret = seccomp_get_filter(child, addr, datavp);
+ break;
+
default:
break;
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 06858a7..580ac2d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -347,6 +347,7 @@ static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
{
struct seccomp_filter *sfilter;
int ret;
+ const bool save_orig = config_enabled(CONFIG_CHECKPOINT_RESTORE);
if (fprog->len == 0 || fprog->len > BPF_MAXINSNS)
return ERR_PTR(-EINVAL);
@@ -370,7 +371,7 @@ static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
return ERR_PTR(-ENOMEM);
ret = bpf_prog_create_from_user(&sfilter->prog, fprog,
- seccomp_check_filter, false);
+ seccomp_check_filter, save_orig);
if (ret < 0) {
kfree(sfilter);
return ERR_PTR(ret);
@@ -867,3 +868,76 @@ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
/* prctl interface doesn't have flags, so they are always zero. */
return do_seccomp(op, 0, uargs);
}
+
+#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
+long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
+ void __user *data)
+{
+ struct seccomp_filter *filter;
+ struct sock_fprog_kern *fprog;
+ long ret;
+ unsigned long count = 0;
+
+ if (!capable(CAP_SYS_ADMIN) ||
+ current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+ return -EACCES;
+ }
+
+ spin_lock_irq(&task->sighand->siglock);
+ if (task->seccomp.mode != SECCOMP_MODE_FILTER) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ filter = task->seccomp.filter;
+ while (filter) {
+ filter = filter->prev;
+ count++;
+ }
+
+ if (filter_off >= count) {
+ ret = -ENOENT;
+ goto out;
+ }
+ count -= filter_off;
+
+ filter = task->seccomp.filter;
+ while (filter && count > 1) {
+ filter = filter->prev;
+ count--;
+ }
+
+ if (WARN_ON(count != 1 || !filter)) {
+ /* The filter tree shouldn't shrink while we're using it. */
+ ret = -ENOENT;
+ goto out;
+ }
+
+ fprog = filter->prog->orig_prog;
+ if (!fprog) {
+ /* This must be a new non-cBPF filter, since we save every
+ * every cBPF filter's orig_prog above when
+ * CONFIG_CHECKPOINT_RESTORE is enabled.
+ */
+ ret = -EMEDIUMTYPE;
+ goto out;
+ }
+
+ ret = fprog->len;
+ if (!data)
+ goto out;
+
+ get_seccomp_filter(task);
+ spin_unlock_irq(&task->sighand->siglock);
+
+ if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
+ ret = -EFAULT;
+
+ put_seccomp_filter(task);
+ return ret;
+
+out:
+ spin_unlock_irq(&task->sighand->siglock);
+ return ret;
+}
+#endif
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