netdev - [PATCH AUTOSEL 4.14 46/59] net: macb: fix random memory corruption on RX with 64-bit DMA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Wed, 26 Dec 2018 17:38:26 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Anssi Hannula <anssi.hannula@...wise.fi>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Michal Simek <michal.simek@...inx.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 46/59] net: macb: fix random memory corruption on RX with 64-bit DMA

From: Anssi Hannula <anssi.hannula@...wise.fi>

[ Upstream commit e100a897bf9b19089e57f236f2398c9e0538900e ]

64-bit DMA addresses are split in upper and lower halves that are
written in separate fields on GEM. For RX, bit 0 of the address is used
as the ownership bit (RX_USED). When the RX_USED bit is unset the
controller is allowed to write data to the buffer.

The driver does not guarantee that the controller already sees the upper
half when the RX_USED bit is cleared, possibly resulting in the
controller writing an incoming frame to an address with an incorrect
upper half and therefore possibly corrupting unrelated system memory.

Fix that by adding the necessary DMA memory barrier between the writes.

This corruption was observed on a ZynqMP based system.

Fixes: fff8019a08b6 ("net: macb: Add 64 bit addressing support for GEM")
Signed-off-by: Anssi Hannula <anssi.hannula@...wise.fi>
Acked-by: Harini Katakam <harini.katakam@...inx.com>
Tested-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>
Cc: Michal Simek <michal.simek@...inx.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/ethernet/cadence/macb_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index d6f8d6c8b0f1..db5be65b2553 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -674,6 +674,11 @@ static void macb_set_addr(struct macb *bp, struct macb_dma_desc *desc, dma_addr_
 	if (bp->hw_dma_cap & HW_DMA_CAP_64B) {
 		desc_64 = macb_64b_desc(bp, desc);
 		desc_64->addrh = upper_32_bits(addr);
+		/* The low bits of RX address contain the RX_USED bit, clearing
+		 * of which allows packet RX. Make sure the high bits are also
+		 * visible to HW at that point.
+		 */
+		dma_wmb();
 	}
 #endif
 	desc->addr = lower_32_bits(addr);
-- 
2.19.1