From 20b1b6cf4ead777a78503c286f3f7026909029fb Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 1 Feb 2019 11:28:16 +0300 Subject: [PATCH] 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: 83c45daa94bd ("[PATCH] skge: expand ethtool debug register dump") Signed-off-by: Dan Carpenter Signed-off-by: David S. Miller --- drivers/net/ethernet/marvell/skge.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/marvell/skge.c b/drivers/net/ethernet/marvell/skge.c index 04fd1f135011f..654ac534b10e3 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 */ -- 2.39.5