59 lines
2.2 KiB
Diff
59 lines
2.2 KiB
Diff
From ba42ebb863ab7d40adc79298422ed9596df8f73a Mon Sep 17 00:00:00 2001
|
|
From: Li Qiang <liqiang6-s@360.cn>
|
|
Date: Mon, 17 Oct 2016 14:13:58 +0200
|
|
Subject: [PATCH] 9pfs: allocate space for guest originated empty strings
|
|
|
|
If a guest sends an empty string paramater to any 9P operation, the current
|
|
code unmarshals it into a V9fsString equal to { .size = 0, .data = NULL }.
|
|
|
|
This is unfortunate because it can cause NULL pointer dereference to happen
|
|
at various locations in the 9pfs code. And we don't want to check str->data
|
|
everywhere we pass it to strcmp() or any other function which expects a
|
|
dereferenceable pointer.
|
|
|
|
This patch enforces the allocation of genuine C empty strings instead, so
|
|
callers don't have to bother.
|
|
|
|
Out of all v9fs_iov_vunmarshal() users, only v9fs_xattrwalk() checks if
|
|
the returned string is empty. It now uses v9fs_string_size() since
|
|
name.data cannot be NULL anymore.
|
|
|
|
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
|
|
[groug, rewritten title and changelog,
|
|
fix empty string check in v9fs_xattrwalk()]
|
|
Signed-off-by: Greg Kurz <groug@kaod.org>
|
|
---
|
|
fsdev/9p-iov-marshal.c | 2 +-
|
|
hw/9pfs/9p.c | 2 +-
|
|
2 files changed, 2 insertions(+), 2 deletions(-)
|
|
|
|
diff --git a/fsdev/9p-iov-marshal.c b/fsdev/9p-iov-marshal.c
|
|
index 663cad5..1d16f8d 100644
|
|
--- a/fsdev/9p-iov-marshal.c
|
|
+++ b/fsdev/9p-iov-marshal.c
|
|
@@ -125,7 +125,7 @@ ssize_t v9fs_iov_vunmarshal(struct iovec *out_sg, int out_num, size_t offset,
|
|
str->data = g_malloc(str->size + 1);
|
|
copied = v9fs_unpack(str->data, out_sg, out_num, offset,
|
|
str->size);
|
|
- if (copied > 0) {
|
|
+ if (copied >= 0) {
|
|
str->data[str->size] = 0;
|
|
} else {
|
|
v9fs_string_free(str);
|
|
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
|
|
index 119ee58..39a7e1d 100644
|
|
--- a/hw/9pfs/9p.c
|
|
+++ b/hw/9pfs/9p.c
|
|
@@ -3174,7 +3174,7 @@ static void v9fs_xattrwalk(void *opaque)
|
|
goto out;
|
|
}
|
|
v9fs_path_copy(&xattr_fidp->path, &file_fidp->path);
|
|
- if (name.data == NULL) {
|
|
+ if (!v9fs_string_size(&name)) {
|
|
/*
|
|
* listxattr request. Get the size first
|
|
*/
|
|
--
|
|
2.7.3
|
|
|