From 8ffb7265af64ec81748335ec8f20e7ab542c3850 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Tue, 24 Mar 2020 22:57:22 +0530 Subject: [PATCH] net: tulip: check frame size and r/w data length Tulip network driver while copying tx/rx buffers does not check frame size against r/w data length. This may lead to OOB buffer access. Add check to avoid it. Limit iterations over descriptors to avoid potential infinite loop issue in tulip_xmit_list_update. Reported-by: Li Qiang Reported-by: Ziming Zhang Reported-by: Jason Wang Tested-by: Li Qiang Reviewed-by: Li Qiang Signed-off-by: Prasad J Pandit Signed-off-by: Jason Wang Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=8ffb7265af64ec81748335ec8f20e7ab542c3850] CVE: CVE-2020-11102 Signed-off-by: Chee Yang Lee --- hw/net/tulip.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) diff --git a/hw/net/tulip.c b/hw/net/tulip.c index cfac271..1295f51 100644 --- a/hw/net/tulip.c +++ b/hw/net/tulip.c @@ -170,6 +170,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct tulip_descriptor *desc) } else { len = s->rx_frame_len; } + + if (s->rx_frame_len + len > sizeof(s->rx_frame)) { + return; + } pci_dma_write(&s->dev, desc->buf_addr1, s->rx_frame + (s->rx_frame_size - s->rx_frame_len), len); s->rx_frame_len -= len; @@ -181,6 +185,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct tulip_descriptor *desc) } else { len = s->rx_frame_len; } + + if (s->rx_frame_len + len > sizeof(s->rx_frame)) { + return; + } pci_dma_write(&s->dev, desc->buf_addr2, s->rx_frame + (s->rx_frame_size - s->rx_frame_len), len); s->rx_frame_len -= len; @@ -227,7 +235,8 @@ static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size) trace_tulip_receive(buf, size); - if (size < 14 || size > 2048 || s->rx_frame_len || tulip_rx_stopped(s)) { + if (size < 14 || size > sizeof(s->rx_frame) - 4 + || s->rx_frame_len || tulip_rx_stopped(s)) { return 0; } @@ -275,7 +284,6 @@ static ssize_t tulip_receive_nc(NetClientState *nc, return tulip_receive(qemu_get_nic_opaque(nc), buf, size); } - static NetClientInfo net_tulip_info = { .type = NET_CLIENT_DRIVER_NIC, .size = sizeof(NICState), @@ -558,7 +566,7 @@ static void tulip_tx(TULIPState *s, struct tulip_descriptor *desc) if ((s->csr[6] >> CSR6_OM_SHIFT) & CSR6_OM_MASK) { /* Internal or external Loopback */ tulip_receive(s, s->tx_frame, s->tx_frame_len); - } else { + } else if (s->tx_frame_len <= sizeof(s->tx_frame)) { qemu_send_packet(qemu_get_queue(s->nic), s->tx_frame, s->tx_frame_len); } @@ -570,23 +578,31 @@ static void tulip_tx(TULIPState *s, struct tulip_descriptor *desc) } } -static void tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor *desc) +static int tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor *desc) { int len1 = (desc->control >> TDES1_BUF1_SIZE_SHIFT) & TDES1_BUF1_SIZE_MASK; int len2 = (desc->control >> TDES1_BUF2_SIZE_SHIFT) & TDES1_BUF2_SIZE_MASK; + if (s->tx_frame_len + len1 > sizeof(s->tx_frame)) { + return -1; + } if (len1) { pci_dma_read(&s->dev, desc->buf_addr1, s->tx_frame + s->tx_frame_len, len1); s->tx_frame_len += len1; } + if (s->tx_frame_len + len2 > sizeof(s->tx_frame)) { + return -1; + } if (len2) { pci_dma_read(&s->dev, desc->buf_addr2, s->tx_frame + s->tx_frame_len, len2); s->tx_frame_len += len2; } desc->status = (len1 + len2) ? 0 : 0x7fffffff; + + return 0; } static void tulip_setup_filter_addr(TULIPState *s, uint8_t *buf, int n) @@ -651,13 +667,15 @@ static uint32_t tulip_ts(TULIPState *s) static void tulip_xmit_list_update(TULIPState *s) { +#define TULIP_DESC_MAX 128 + uint8_t i = 0; struct tulip_descriptor desc; if (tulip_ts(s) != CSR5_TS_SUSPENDED) { return; } - for (;;) { + for (i = 0; i < TULIP_DESC_MAX; i++) { tulip_desc_read(s, s->current_tx_desc, &desc); tulip_dump_tx_descriptor(s, &desc); @@ -675,10 +693,10 @@ static void tulip_xmit_list_update(TULIPState *s) s->tx_frame_len = 0; } - tulip_copy_tx_buffers(s, &desc); - - if (desc.control & TDES1_LS) { - tulip_tx(s, &desc); + if (!tulip_copy_tx_buffers(s, &desc)) { + if (desc.control & TDES1_LS) { + tulip_tx(s, &desc); + } } } tulip_desc_write(s, s->current_tx_desc, &desc); -- 1.8.3.1