net/9p: use memcpy() instead of snprintf() in p9_mount_tag_show()
p9_mount_tag_show() uses '%s' format string to print
non-NULL terminated chan->tag string. This leads
to out of bounds memory read, because format '%s'
implies that string is NULL-terminated.
The length of string is know here, so its simpler and safer
to use memcpy instead of snprintf().
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 36a1a73..486df01 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -504,7 +504,10 @@
vdev = dev_to_virtio(dev);
chan = vdev->priv;
- return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
+ memcpy(buf, chan->tag, chan->tag_len);
+ buf[chan->tag_len] = 0;
+
+ return chan->tag_len + 1;
}
static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);