From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42148) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bz0k9-0001em-RY for qemu-devel@nongnu.org; Tue, 25 Oct 2016 08:22:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bz0k8-0005np-Jo for qemu-devel@nongnu.org; Tue, 25 Oct 2016 08:22:13 -0400 From: P J P Date: Tue, 25 Oct 2016 17:52:00 +0530 Message-Id: <1477398120-9000-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] net: smc91c111: check packet number and data register index List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: qemu-arm , Jason Wang , Azure Yang , Prasad J Pandit From: Prasad J Pandit SMSC91C111 Ethernet interface emulator has registers to store 'packet number' and a 'pointer' to Tx/Rx FIFO buffer area. These two are used to derive an address to access into 'data' registers. If they are not set correctly, they could lead to OOB r/w access beyond packet 'data' area. Add check to avoid it. Reported-by: Azure Yang Signed-off-by: Prasad J Pandit --- hw/net/smc91c111.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/hw/net/smc91c111.c b/hw/net/smc91c111.c index 3b16dcf..2425da1 100644 --- a/hw/net/smc91c111.c +++ b/hw/net/smc91c111.c @@ -418,7 +418,7 @@ static void smc91c111_writeb(void *opaque, hwaddr offset, /* Ignore. */ return; case 2: /* Packet Number Register */ - s->packet_num = value; + s->packet_num = value & (NUM_PACKETS - 1); return; case 3: case 4: case 5: /* Should be readonly, but linux writes to them anyway. Ignore. */ @@ -444,7 +444,10 @@ static void smc91c111_writeb(void *opaque, hwaddr offset, } else { p += (offset & 3); } - s->data[n][p] = value; + if (n < NUM_PACKETS + && p < sizeof(s->data[n]) / sizeof(s->data[n][0])) { + s->data[n][p] = value; + } } return; case 12: /* Interrupt ACK. */ @@ -590,7 +593,12 @@ static uint32_t smc91c111_readb(void *opaque, hwaddr offset) } else { p += (offset & 3); } - return s->data[n][p]; + + if (n < NUM_PACKETS + && p < sizeof(s->data[n]) / sizeof(s->data[n][0])) { + return s->data[n][p]; + } + return 0x80; } case 12: /* Interrupt status. */ return s->int_level; -- 2.7.4