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authorTycho Andersen <tycho@docker.com>2017-10-11 09:39:21 -0600
committerKees Cook <keescook@chromium.org>2017-11-28 15:41:01 -0800
commit26500475ac1b499d8636ff281311d633909f5d20 (patch)
treee5b9fbb6661848e22324fc70678bbd432bae2688
parentf06eae831f0c1fc5b982ea200daf552810e1dd55 (diff)
ptrace, seccomp: add support for retrieving seccomp metadata
With the new SECCOMP_FILTER_FLAG_LOG, we need to be able to extract these flags for checkpoint restore, since they describe the state of a filter. So, let's add PTRACE_SECCOMP_GET_METADATA, similar to ..._GET_FILTER, which returns the metadata of the nth filter (right now, just the flags). Hopefully this will be future proof, and new per-filter metadata can be added to this struct. Signed-off-by: Tycho Andersen <tycho@docker.com> CC: Kees Cook <keescook@chromium.org> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
-rw-r--r--include/linux/seccomp.h8
-rw-r--r--include/uapi/linux/ptrace.h6
-rw-r--r--kernel/ptrace.c4
-rw-r--r--kernel/seccomp.c33
4 files changed, 51 insertions, 0 deletions
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index 10f25f7e4304..c723a5c4e3ff 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -95,11 +95,19 @@ static inline void get_seccomp_filter(struct task_struct *tsk)
#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);
+extern long seccomp_get_metadata(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;
}
+static inline long seccomp_get_metadata(struct task_struct *task,
+ unsigned long filter_off,
+ 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 e3939e00980b..e46d82b91166 100644
--- a/include/uapi/linux/ptrace.h
+++ b/include/uapi/linux/ptrace.h
@@ -66,6 +66,12 @@ struct ptrace_peeksiginfo_args {
#define PTRACE_SETSIGMASK 0x420b
#define PTRACE_SECCOMP_GET_FILTER 0x420c
+#define PTRACE_SECCOMP_GET_METADATA 0x420d
+
+struct seccomp_metadata {
+ unsigned long filter_off; /* Input: which filter */
+ unsigned int flags; /* Output: filter's flags */
+};
/* 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 84b1367935e4..58291e9f3276 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1092,6 +1092,10 @@ int ptrace_request(struct task_struct *child, long request,
ret = seccomp_get_filter(child, addr, datavp);
break;
+ case PTRACE_SECCOMP_GET_METADATA:
+ ret = seccomp_get_metadata(child, addr, datavp);
+ break;
+
default:
break;
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 99bddaf79076..61bd9dc260c8 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1061,6 +1061,39 @@ out:
__put_seccomp_filter(filter);
return ret;
}
+
+long seccomp_get_metadata(struct task_struct *task,
+ unsigned long size, void __user *data)
+{
+ long ret;
+ struct seccomp_filter *filter;
+ struct seccomp_metadata kmd = {};
+
+ if (!capable(CAP_SYS_ADMIN) ||
+ current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+ return -EACCES;
+ }
+
+ size = min_t(unsigned long, size, sizeof(kmd));
+
+ if (copy_from_user(&kmd, data, size))
+ return -EFAULT;
+
+ filter = get_nth_filter(task, kmd.filter_off);
+ if (IS_ERR(filter))
+ return PTR_ERR(filter);
+
+ memset(&kmd, 0, sizeof(kmd));
+ if (filter->log)
+ kmd.flags |= SECCOMP_FILTER_FLAG_LOG;
+
+ ret = size;
+ if (copy_to_user(data, &kmd, size))
+ ret = -EFAULT;
+
+ __put_seccomp_filter(filter);
+ return ret;
+}
#endif
#ifdef CONFIG_SYSCTL