From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Mon, 2 Nov 2020 15:44:05 +0000 (+0100)
Subject: seccomp: make seccomp notifier fd non-blocking
X-Git-Tag: lxc-5.0.0~343^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a60c98aaf637f3cb8ef6b054cceab666d2317615;p=thirdparty%2Flxc.git

seccomp: make seccomp notifier fd non-blocking

Suggested-by: Jann Horn <jann@thejh.net>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/file_utils.c b/src/lxc/file_utils.c
index 4a8c7a8d9..fafaba354 100644
--- a/src/lxc/file_utils.c
+++ b/src/lxc/file_utils.c
@@ -577,3 +577,15 @@ int open_beneath(int dir_fd, const char *path, unsigned int flags)
 
 	return openat(dir_fd, path, O_NOFOLLOW | flags);
 }
+
+int fd_make_nonblocking(int fd)
+{
+	int flags;
+
+	flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -1;
+
+	flags &= ~O_NONBLOCK;
+	return fcntl(fd, F_SETFL, flags);
+}
diff --git a/src/lxc/file_utils.h b/src/lxc/file_utils.h
index df3a00d4d..ea9570dd1 100644
--- a/src/lxc/file_utils.h
+++ b/src/lxc/file_utils.h
@@ -76,5 +76,6 @@ __hidden extern int timens_offset_write(clockid_t clk_id, int64_t s_offset, int6
 __hidden extern bool exists_dir_at(int dir_fd, const char *path);
 __hidden extern bool exists_file_at(int dir_fd, const char *path);
 __hidden extern int open_beneath(int dir_fd, const char *path, unsigned int flags);
+__hidden int fd_make_nonblocking(int fd);
 
 #endif /* __LXC_FILE_UTILS_H */
diff --git a/src/lxc/seccomp.c b/src/lxc/seccomp.c
index 4faf693f6..e303561bf 100644
--- a/src/lxc/seccomp.c
+++ b/src/lxc/seccomp.c
@@ -1280,6 +1280,9 @@ int lxc_seccomp_load(struct lxc_conf *conf)
 			return -1;
 		}
 
+		if (fd_make_nonblocking(ret))
+			return log_error_errno(-1, errno, "Failed to make seccomp listener fd non-blocking");;
+
 		conf->seccomp.notifier.notify_fd = ret;
 		TRACE("Retrieved new seccomp listener fd %d", ret);
 	}