| Message ID | 20200217113804.341836-1-ppandit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] net: tulip: check frame size and r/w data length | expand |
On 2020/2/17 下午7:38, P J P wrote: > From: Prasad J Pandit <pjp@fedoraproject.org> > > 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. > > Reported-by: Li Qiang <pangpei.lq@antfin.com> > Reported-by: Ziming Zhang <ezrakiez@gmail.com> > Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> > --- > hw/net/tulip.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > Update v2: retain earlier len[12] & s->rx_frame_len checks > -> https://lists.gnu.org/archive/html/qemu-devel/2020-02/msg04160.html > > diff --git a/hw/net/tulip.c b/hw/net/tulip.c > index cfac2719d3..ea4fd371e3 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; > + } What's the goal of this checking? > 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; It's better to move those checks in .can_receive(). > } > > @@ -558,7 +567,7 @@ 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)) { Should we use <= here? > qemu_send_packet(qemu_get_queue(s->nic), > s->tx_frame, s->tx_frame_len); > } > @@ -575,12 +584,18 @@ static void 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; > + } I think it's better to add a return value here to make sure caller tulip_xmit_list_update() can exit the loop early > 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; > + } > if (len2) { > pci_dma_read(&s->dev, desc->buf_addr2, > s->tx_frame + s->tx_frame_len, len2); One more thing. It looks to me there could be a user trigger-able infinite loop in tun_list_update() through always set TDES0_OWN in its descriptors? Thanks
+-- On Mon, 24 Feb 2020, Jason Wang wrote --+
| > + if (s->rx_frame_len + len >= sizeof(s->rx_frame)) {
| > + return;
| > + }
| What's the goal of this checking?
To avoid potential OOB access while in pci_dma_write().
| > pci_dma_write(&s->dev, desc->buf_addr2, s->rx_frame +
| > (s->rx_frame_size - s->rx_frame_len), len);
|
| > + if (size < 14 || size > sizeof(s->rx_frame) - 4
| > + || s->rx_frame_len || tulip_rx_stopped(s)) {
| > return 0;
| It's better to move those checks in .can_receive().
I tried to move these checks to .can_recieve, but tulip_receive()
is called from tulip_receive_nc() and tulip_tx() and the 'size' check could
not be moved to can_receive().
| > + } else if (s->tx_frame_len < sizeof(s->tx_frame)) {
| Should we use <= here?
Done.
| > + if (s->tx_frame_len + len1 >= sizeof(s->tx_frame)) {
| > + return;
| > + }
| I think it's better to add a return value here to make sure caller
| tulip_xmit_list_update() can exit the loop early
Done.
| One more thing.
| It looks to me there could be a user trigger-able infinite loop in
| tun_list_update() through always set TDES0_OWN in its descriptors?
Yes, defined TULIP_DESC_MAX=128 to restrict loop iterations to 128
descriptors to avoid potential infinite loop.
-> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/ethernet/dec/tulip/tulip.h#n319
Sent patch v3 with above changes; Sorry about the delay.
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
diff --git a/hw/net/tulip.c b/hw/net/tulip.c index cfac2719d3..ea4fd371e3 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; } @@ -558,7 +567,7 @@ 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); } @@ -575,12 +584,18 @@ static void 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; + } 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; + } if (len2) { pci_dma_read(&s->dev, desc->buf_addr2, s->tx_frame + s->tx_frame_len, len2);