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 <groug@kaod.org>
---
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 7f3d9dd9a499..ebc12f3c0691 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1072,13 +1072,11 @@ 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;
}