linux-kernel - [PATCH AUTOSEL 5.4 085/130] MIPS: KASLR: Avoid endless loop in sync_icache if synci

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

Message-Id: <20201223021813.2791612-85-sashal@kernel.org>
Date:   Tue, 22 Dec 2020 21:17:28 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Jinyang He <hejinyang@...ngson.cn>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Sasha Levin <sashal@...nel.org>, linux-mips@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 085/130] MIPS: KASLR: Avoid endless loop in sync_icache if synci_step is zero

From: Jinyang He <hejinyang@...ngson.cn>

[ Upstream commit c0aac3a51cb6364bed367ee3e1a96ed414f386b4 ]

Most platforms do not need to do synci instruction operations when
synci_step is 0. But for example, the synci implementation on Loongson64
platform has some changes. On the one hand, it ensures that the memory
access instructions have been completed. On the other hand, it guarantees
that all prefetch instructions need to be fetched again. And its address
information is useless. Thus, only one synci operation is required when
synci_step is 0 on Loongson64 platform. I guess that some other platforms
have similar implementations on synci, so add judgment conditions in
`while` to ensure that at least all platforms perform synci operations
once. For those platforms that do not need synci, they just do one more
operation similar to nop.

Signed-off-by: Jinyang He <hejinyang@...ngson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/mips/kernel/relocate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c
index 3d80a51256de6..cf92196ab6145 100644
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -64,7 +64,7 @@ static void __init sync_icache(void *kbase, unsigned long kernel_length)
 			: "r" (kbase));

 		kbase += step;
-	} while (kbase < kend);
+	} while (step && kbase < kend);

 	/* Completion barrier */
 	__sync();
-- 
2.27.0