From cde31a0e3dc0e4ac83e454d6096350cec584adf1 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 7 Mar 2012 11:17:48 +0800 Subject: [PATCH] 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 Reviewed-by: Stefan Hajnoczi Signed-off-by: Michael S. Tsirkin --- hw/rtl8139.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/hw/rtl8139.c b/hw/rtl8139.c index 05b8e1e3d7..be4bc6a947 100644 --- a/hw/rtl8139.c +++ b/hw/rtl8139.c @@ -2061,13 +2061,12 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) 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) -- GitLab