From a639731ba9d38108bb8b061db42d6694c64bcb37 Mon Sep 17 00:00:00 2001
From: Alan Somers <asomers@FreeBSD.org>
Date: Mon, 3 Jun 2019 23:24:07 +0000
Subject: [PATCH] fusefs: respect RLIMIT_FSIZE

Sponsored by:	The FreeBSD Foundation
---
 sys/fs/fuse/fuse_io.c        |  6 ++++
 tests/sys/fs/fusefs/write.cc | 55 ++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/sys/fs/fuse/fuse_io.c b/sys/fs/fuse/fuse_io.c
index e76ec80584f4..d760a93146ba 100644
--- a/sys/fs/fuse/fuse_io.c
+++ b/sys/fs/fuse/fuse_io.c
@@ -447,6 +447,9 @@ fuse_write_directbackend(struct vnode *vp, struct uio *uio,
 	if (ioflag & IO_APPEND)
 		uio_setoffset(uio, filesize);
 
+	if (vn_rlimit_fsize(vp, uio, uio->uio_td))
+		return (EFBIG);
+
 	fdisp_init(&fdi, 0);
 
 	while (uio->uio_resid > 0) {
@@ -579,6 +582,9 @@ fuse_write_biobackend(struct vnode *vp, struct uio *uio,
 	if (ioflag & IO_APPEND)
 		uio_setoffset(uio, filesize);
 
+	if (vn_rlimit_fsize(vp, uio, uio->uio_td))
+		return (EFBIG);
+
 	/*
          * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
          * would exceed the local maximum per-file write commit size when
diff --git a/tests/sys/fs/fusefs/write.cc b/tests/sys/fs/fusefs/write.cc
index 95ad364edf94..242f442c6a9a 100644
--- a/tests/sys/fs/fusefs/write.cc
+++ b/tests/sys/fs/fusefs/write.cc
@@ -31,12 +31,15 @@
 extern "C" {
 #include <sys/types.h>
 #include <sys/mman.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/sysctl.h>
+#include <sys/time.h>
 #include <sys/uio.h>
 
 #include <aio.h>
 #include <fcntl.h>
+#include <signal.h>
 #include <unistd.h>
 }
 
@@ -48,6 +51,22 @@ using namespace testing;
 class Write: public FuseTest {
 
 public:
+static sig_atomic_t s_sigxfsz;
+
+void SetUp() {
+	s_sigxfsz = 0;
+	FuseTest::SetUp();
+}
+
+void TearDown() {
+	struct sigaction sa;
+
+	bzero(&sa, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+	sigaction(SIGXFSZ, &sa, NULL);
+
+	FuseTest::TearDown();
+}
 
 void expect_lookup(const char *relpath, uint64_t ino, uint64_t size)
 {
@@ -73,6 +92,8 @@ void expect_write(uint64_t ino, uint64_t offset, uint64_t isize,
 
 };
 
+sig_atomic_t Write::s_sigxfsz = 0;
+
 class Write_7_8: public FuseTest {
 
 public:
@@ -158,6 +179,10 @@ void expect_write(uint64_t ino, uint64_t offset, uint64_t isize,
 }
 };
 
+void sigxfsz_handler(int __unused sig) {
+	Write::s_sigxfsz = 1;
+}
+
 /* AIO writes need to set the header's pid field correctly */
 /* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236379 */
 TEST_F(AioWrite, DISABLED_aio_write)
@@ -372,6 +397,36 @@ TEST_F(Write, direct_io_short_write_iov)
 	/* Deliberately leak fd.  close(2) will be tested in release.cc */
 }
 
+/* fusefs should respect RLIMIT_FSIZE */
+TEST_F(Write, rlimit_fsize)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	const char *CONTENTS = "abcdefgh";
+	struct rlimit rl;
+	ssize_t bufsize = strlen(CONTENTS);
+	off_t offset = 1'000'000'000;
+	uint64_t ino = 42;
+	int fd;
+
+	expect_lookup(RELPATH, ino, 0);
+	expect_open(ino, 0, 1);
+
+	rl.rlim_cur = offset;
+	rl.rlim_max = 10 * offset;
+	ASSERT_EQ(0, setrlimit(RLIMIT_FSIZE, &rl)) << strerror(errno);
+	ASSERT_NE(SIG_ERR, signal(SIGXFSZ, sigxfsz_handler)) << strerror(errno);
+
+	fd = open(FULLPATH, O_WRONLY);
+
+	EXPECT_LE(0, fd) << strerror(errno);
+
+	ASSERT_EQ(-1, pwrite(fd, CONTENTS, bufsize, offset));
+	EXPECT_EQ(EFBIG, errno);
+	EXPECT_EQ(1, s_sigxfsz);
+	/* Deliberately leak fd.  close(2) will be tested in release.cc */
+}
+
 /*
  * If the kernel cannot be sure which uid, gid, or pid was responsible for a
  * write, then it must set the FUSE_WRITE_CACHE bit