From: Dan Carpenter Date: Fri, 1 Feb 2019 08:28:16 +0000 (+0300) Subject: skge: potential memory corruption in skge_get_regs() X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=294c149a209c6196c2de85f512b52ef50f519949;p=openwrt%2Fstaging%2Fblogic.git skge: potential memory corruption in skge_get_regs() The "p" buffer is 0x4000 bytes long. B3_RI_WTO_R1 is 0x190. The value of "regs->len" is in the 1-0x4000 range. The bug here is that "regs->len - B3_RI_WTO_R1" can be a negative value which would lead to memory corruption and an abrupt crash. Fixes: c3f8be961808 ("[PATCH] skge: expand ethtool debug register dump") Signed-off-by: Dan Carpenter Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c index 04fd1f135011..654ac534b10e 100644 --- a/drivers/net/ethernet/marvell/skge.c +++ b/drivers/net/ethernet/marvell/skge.c @@ -152,8 +152,10 @@ static void skge_get_regs(struct net_device *dev, struct ethtool_regs *regs, memset(p, 0, regs->len); memcpy_fromio(p, io, B3_RAM_ADDR); - memcpy_fromio(p + B3_RI_WTO_R1, io + B3_RI_WTO_R1, - regs->len - B3_RI_WTO_R1); + if (regs->len > B3_RI_WTO_R1) { + memcpy_fromio(p + B3_RI_WTO_R1, io + B3_RI_WTO_R1, + regs->len - B3_RI_WTO_R1); + } } /* Wake on Lan only supported on Yukon chips with rev 1 or above */