Hello Laurent, On 11/8/18 10:10 AM, Laurent Vivier wrote: > On 26/10/2018 14:33, P J P wrote: >> From: Prasad J Pandit <p...@fedoraproject.org> >> >> While performing PowerNV memory r/w operations, the access length >> 'sz' could exceed the data[4] buffer size. Add check to avoid OOB >> access. >> >> Reported-by: Moguofang <moguof...@huawei.com> >> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> >> --- >> hw/ppc/pnv_lpc.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> Update v2: add error log message >> -> https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg05750.html >> >> diff --git a/hw/ppc/pnv_lpc.c b/hw/ppc/pnv_lpc.c >> index d7721320a2..172a915cfc 100644 >> --- a/hw/ppc/pnv_lpc.c >> +++ b/hw/ppc/pnv_lpc.c >> @@ -155,9 +155,15 @@ static void pnv_lpc_do_eccb(PnvLpcController *lpc, >> uint64_t cmd) >> /* XXX Check for magic bits at the top, addr size etc... */ >> unsigned int sz = (cmd & ECCB_CTL_SZ_MASK) >> ECCB_CTL_SZ_LSH; >> uint32_t opb_addr = cmd & ECCB_CTL_ADDR_MASK; >> - uint8_t data[4]; >> + uint8_t data[8]; >> bool success; > > I'm not sure 8 is enough. > > ECCB_CTL_SZ_MASK is PPC_BITMASK(4, 7), and ECCB_CTL_SZ_LSH is (63 - 7). > So the bitmask is 4 bits wide, and thus sz can be 0 to 15. > I think data[] size should be 16.
The bitmask allows more that 8 but the specs says that 1, 2, 4, 8 are the possible value size. So We should be fine. C. > > Thanks, > Laurent >
