From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 20 May 2013 17:34:29 +0000 (+0530)
Subject: hw/9pfs: use O_NOFOLLOW for mapped readlink operation
X-Git-Tag: v1.4.2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f890185392aac149caf0631112049f2fb2e0cb41;p=thirdparty%2Fqemu.git

hw/9pfs: use O_NOFOLLOW for mapped readlink operation

With mapped security models like mapped-xattr and mapped-file, we save the
symlink target as file contents. Now if we ever expose a normal directory
with mapped security model and find real symlinks in export path, never
follow them and return proper error.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---

diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index f1b1c83a226..aeaecd8c361 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -284,7 +284,7 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
         int fd;
-        fd = open(rpath(fs_ctx, path, buffer), O_RDONLY);
+        fd = open(rpath(fs_ctx, path, buffer), O_RDONLY | O_NOFOLLOW);
         if (fd == -1) {
             return -1;
         }