qemu-kvm/SOURCES/kvm-virtiofsd-validate-path-components.patch

165 lines
4.9 KiB
Diff

From 69ac47502848c37ca3ede00f432c0675d9eef42c Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Date: Mon, 27 Jan 2020 19:01:18 +0100
Subject: [PATCH 047/116] virtiofsd: validate path components
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: <20200127190227.40942-44-dgilbert@redhat.com>
Patchwork-id: 93498
O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 043/112] virtiofsd: validate path components
Bugzilla: 1694164
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
From: Stefan Hajnoczi <stefanha@redhat.com>
Several FUSE requests contain single path components. A correct FUSE
client sends well-formed path components but there is currently no input
validation in case something went wrong or the client is malicious.
Refuse ".", "..", and paths containing '/' when we expect a path
component.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit 25dae28c58d7e706b5d5db99042c9db3cef2e657)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 59 ++++++++++++++++++++++++++++++++++++----
1 file changed, 53 insertions(+), 6 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index ac380ef..e375406 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -133,6 +133,21 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n);
static struct lo_inode *lo_find(struct lo_data *lo, struct stat *st);
+static int is_dot_or_dotdot(const char *name)
+{
+ return name[0] == '.' &&
+ (name[1] == '\0' || (name[1] == '.' && name[2] == '\0'));
+}
+
+/* Is `path` a single path component that is not "." or ".."? */
+static int is_safe_path_component(const char *path)
+{
+ if (strchr(path, '/')) {
+ return 0;
+ }
+
+ return !is_dot_or_dotdot(path);
+}
static struct lo_data *lo_data(fuse_req_t req)
{
@@ -681,6 +696,15 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
parent, name);
}
+ /*
+ * Don't use is_safe_path_component(), allow "." and ".." for NFS export
+ * support.
+ */
+ if (strchr(name, '/')) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
err = lo_do_lookup(req, parent, name, &e);
if (err) {
fuse_reply_err(req, err);
@@ -762,6 +786,11 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent,
struct fuse_entry_param e;
struct lo_cred old = {};
+ if (!is_safe_path_component(name)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
dir = lo_inode(req, parent);
if (!dir) {
fuse_reply_err(req, EBADF);
@@ -863,6 +892,11 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent,
struct fuse_entry_param e;
int saverr;
+ if (!is_safe_path_component(name)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
inode = lo_inode(req, ino);
if (!inode) {
fuse_reply_err(req, EBADF);
@@ -904,6 +938,10 @@ out_err:
static void lo_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name)
{
int res;
+ if (!is_safe_path_component(name)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
res = unlinkat(lo_fd(req, parent), name, AT_REMOVEDIR);
@@ -916,6 +954,11 @@ static void lo_rename(fuse_req_t req, fuse_ino_t parent, const char *name,
{
int res;
+ if (!is_safe_path_component(name) || !is_safe_path_component(newname)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
if (flags) {
fuse_reply_err(req, EINVAL);
return;
@@ -930,6 +973,11 @@ static void lo_unlink(fuse_req_t req, fuse_ino_t parent, const char *name)
{
int res;
+ if (!is_safe_path_component(name)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
res = unlinkat(lo_fd(req, parent), name, 0);
fuse_reply_err(req, res == -1 ? errno : 0);
@@ -1093,12 +1141,6 @@ out_err:
fuse_reply_err(req, error);
}
-static int is_dot_or_dotdot(const char *name)
-{
- return name[0] == '.' &&
- (name[1] == '\0' || (name[1] == '.' && name[2] == '\0'));
-}
-
static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
off_t offset, struct fuse_file_info *fi, int plus)
{
@@ -1248,6 +1290,11 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
parent, name);
}
+ if (!is_safe_path_component(name)) {
+ fuse_reply_err(req, EINVAL);
+ return;
+ }
+
err = lo_change_cred(req, &old);
if (err) {
goto out;
--
1.8.3.1