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hw/net/xgmac: Fix buffer overflow in xgmac_enet_send() 

A buffer overflow issue was reported by Mr. Ziming Zhang, CC'd here. It
occurs while sending an Ethernet frame due to missing break statements
and improper checking of the buffer size.

Reported-by: Ziming Zhang <ezrakiez@gmail.com>
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Mauro Matteo Cascella 2020-07-10 11:19:41 +02:00 committed by Jason Wang
parent e219d30910
commit 5519724a13
1 changed files with 12 additions and 2 deletions
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14
hw/net/xgmac.c
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@ -220,21 +220,31 @@ static void xgmac_enet_send(XgmacState *s)
}
len = (bd.buffer1_size & 0xfff) + (bd.buffer2_size & 0xfff);
/*
* FIXME: these cases of malformed tx descriptors (bad sizes)
* should probably be reported back to the guest somehow
* rather than simply silently stopping processing, but we
* don't know what the hardware does in this situation.
* This will only happen for buggy guests anyway.
*/
if ((bd.buffer1_size & 0xfff) > 2048) {
DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
"xgmac buffer 1 len on send > 2048 (0x%x)\n",
__func__, bd.buffer1_size & 0xfff);
break;
}
if ((bd.buffer2_size & 0xfff) != 0) {
DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
"xgmac buffer 2 len on send != 0 (0x%x)\n",
__func__, bd.buffer2_size & 0xfff);
break;
}
if (len >= sizeof(frame)) {
if (frame_size + len >= sizeof(frame)) {
DEBUGF_BRK("qemu:%s: buffer overflow %d read into %zu "
"buffer\n" , __func__, len, sizeof(frame));
"buffer\n" , __func__, frame_size + len, sizeof(frame));
DEBUGF_BRK("qemu:%s: buffer1.size=%d; buffer2.size=%d\n",
__func__, bd.buffer1_size, bd.buffer2_size);
break;
}
cpu_physical_memory_read(bd.buffer1_addr, ptr, len);