diff options
| author | Alistair Francis <alistair.francis@xilinx.com> | 2016-06-27 15:37:32 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-06-27 15:37:32 +0100 |
| commit | f265ae8c79ce8c194de481e9def1daa3a80dbb96 (patch) | |
| tree | 29d38fee3b74d00b5a8652d75a57af742f4a9703 /hw/net | |
| parent | f6cf41932edf260c2574346a08358ad2d20c357e (diff) | |
cadence_gem: Avoid infinite loops with a misconfigured buffer
A guest can write zero to the DMACFG resulting in an infinite loop when
it reaches the while(bytes_to_copy) loop.
To avoid this issue enforce a minimum size for the RX buffer. Hardware
does not have this enforcement and relies on the guest to set a non-zero
value.
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reported-by: Li Qiang <liqiang6-s@360.cn>
Reported-by: P J P <ppandit@redhat.com>
Message-id: 84bb1c391b833275da3f573d4972920cea34c188.1466539342.git.alistair.francis@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'hw/net')
| -rw-r--r-- | hw/net/cadence_gem.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c index 0346f3e335..e5f3c985a4 100644 --- a/hw/net/cadence_gem.c +++ b/hw/net/cadence_gem.c @@ -664,6 +664,13 @@ static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size) GEM_DMACFG_RBUFSZ_S) * GEM_DMACFG_RBUFSZ_MUL; bytes_to_copy = size; + /* Hardware allows a zero value here but warns against it. To avoid QEMU + * indefinite loops we enforce a minimum value here + */ + if (rxbufsize < GEM_DMACFG_RBUFSZ_MUL) { + rxbufsize = GEM_DMACFG_RBUFSZ_MUL; + } + /* Pad to minimum length. Assume FCS field is stripped, logic * below will increment it to the real minimum of 64 when * not FCS stripping |