rtl8139: limit transmission buffer size in c+ mode
The tx buffer would be re-allocated for tx descriptor with big size
and without LS bit set, this would make guest driver could easily let
qemu to allocate unlimited.
In linux host, a glib failure were easy to be triggered:
GLib-ERROR **: gmem.c:176: failed to allocate 18446744071562067968 bytes
This patch fix this by adding a limit. As the spec didn't tell the maximum size
of buffer allowed, stick it to current CP_TX_BUFFER_SIZE (65536).
Changes from V1:
Drop the while statement and s->cplus_txbuffer check.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/rtl8139.c b/hw/rtl8139.c
index 05b8e1e..be4bc6a 100644
--- a/hw/rtl8139.c
+++ b/hw/rtl8139.c
@@ -2061,13 +2061,12 @@
s->cplus_txbuffer_len);
}
- while (s->cplus_txbuffer && s->cplus_txbuffer_offset + txsize >= s->cplus_txbuffer_len)
+ if (s->cplus_txbuffer_offset + txsize >= s->cplus_txbuffer_len)
{
- s->cplus_txbuffer_len += CP_TX_BUFFER_SIZE;
- s->cplus_txbuffer = g_realloc(s->cplus_txbuffer, s->cplus_txbuffer_len);
-
- DPRINTF("+++ C+ mode transmission buffer space changed to %d\n",
- s->cplus_txbuffer_len);
+ /* The spec didn't tell the maximum size, stick to CP_TX_BUFFER_SIZE */
+ txsize = s->cplus_txbuffer_len - s->cplus_txbuffer_offset;
+ DPRINTF("+++ C+ mode transmission buffer overrun, truncated descriptor"
+ "length to %d\n", txsize);
}
if (!s->cplus_txbuffer)
