From 31e51d1c15b35dc98b88a301812914b70a2b55dc Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Sun, 26 Feb 2017 23:43:25 +0100 Subject: [PATCH] 9pfs: local: statfs: don't follow symlinks The local_statfs() callback is vulnerable to symlink attacks because it calls statfs() which follows symbolic links in all path elements. This patch converts local_statfs() to rely on open_nofollow() and fstatfs() instead. This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz Reviewed-by: Stefan Hajnoczi --- hw/9pfs/9p-local.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index a6dd77d7b8..95b2c1c341 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -1077,13 +1077,11 @@ static int local_fsync(FsContext *ctx, int fid_type, static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) { - char *buffer; - int ret; - char *path = fs_path->data; + int fd, ret; - buffer = rpath(s, path); - ret = statfs(buffer, stbuf); - g_free(buffer); + fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0); + ret = fstatfs(fd, stbuf); + close_preserve_errno(fd); return ret; }