linux-kernel - [PATCH AUTOSEL 4.9 17/90] kernel/sys.c: avoid copying possible padding bytes in copy_to

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: <20200918021455.2067301-17-sashal@kernel.org>
Date:   Thu, 17 Sep 2020 22:13:42 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Joe Perches <joe@...ches.com>, Dan Carpenter <error27@...il.com>,
        Julia Lawall <julia.lawall@...6.fr>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kees Cook <keescook@...omium.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 17/90] kernel/sys.c: avoid copying possible padding bytes in copy_to_user

From: Joe Perches <joe@...ches.com>

[ Upstream commit 5e1aada08cd19ea652b2d32a250501d09b02ff2e ]

Initialization is not guaranteed to zero padding bytes so use an
explicit memset instead to avoid leaking any kernel content in any
possible padding bytes.

Link: http://lkml.kernel.org/r/dfa331c00881d61c8ee51577a082d8bebd61805c.camel@perches.com
Signed-off-by: Joe Perches <joe@...ches.com>
Cc: Dan Carpenter <error27@...il.com>
Cc: Julia Lawall <julia.lawall@...6.fr>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Kees Cook <keescook@...omium.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/sys.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index 157277cbf83aa..546cdc911dad4 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1183,11 +1183,13 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
 
 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
 {
-	struct oldold_utsname tmp = {};
+	struct oldold_utsname tmp;
 
 	if (!name)
 		return -EFAULT;
 
+	memset(&tmp, 0, sizeof(tmp));
+
 	down_read(&uts_sem);
 	memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
 	memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
-- 
2.25.1