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: <20190929173244.8918-41-sashal@kernel.org>
Date:   Sun, 29 Sep 2019 13:32:40 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Alexandre Ghiti <alex@...ti.fr>, Kees Cook <keescook@...omium.org>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Albert Ou <aou@...s.berkeley.edu>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Hellwig <hch@...radead.org>,
        Christoph Hellwig <hch@....de>,
        James Hogan <jhogan@...nel.org>,
        Palmer Dabbelt <palmer@...ive.com>,
        Paul Burton <paul.burton@...s.com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Russell King <linux@...linux.org.uk>,
        Will Deacon <will.deacon@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 5.2 41/42] arm: properly account for stack randomization and stack guard gap

From: Alexandre Ghiti <alex@...ti.fr>

[ Upstream commit af0f4297286f13a75edf93677b1fb2fc16c412a7 ]

This commit takes care of stack randomization and stack guard gap when
computing mmap base address and checks if the task asked for
randomization.  This fixes the problem uncovered and not fixed for arm
here: https://lkml.kernel.org/r/20170622200033.25714-1-riel@redhat.com

Link: http://lkml.kernel.org/r/20190730055113.23635-7-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@...ti.fr>
Acked-by: Kees Cook <keescook@...omium.org>
Reviewed-by: Luis Chamberlain <mcgrof@...nel.org>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: Christoph Hellwig <hch@....de>
Cc: James Hogan <jhogan@...nel.org>
Cc: Palmer Dabbelt <palmer@...ive.com>
Cc: Paul Burton <paul.burton@...s.com>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Russell King <linux@...linux.org.uk>
Cc: Will Deacon <will.deacon@....com>
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>
---
 arch/arm/mm/mmap.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f866870db749c..bff3d00bda5be 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -18,8 +18,9 @@
 	 (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
 
 /* gap between mmap and stack */
-#define MIN_GAP (128*1024*1024UL)
-#define MAX_GAP ((TASK_SIZE)/6*5)
+#define MIN_GAP		(128*1024*1024UL)
+#define MAX_GAP		((TASK_SIZE)/6*5)
+#define STACK_RND_MASK	(0x7ff >> (PAGE_SHIFT - 12))
 
 static int mmap_is_legacy(struct rlimit *rlim_stack)
 {
@@ -35,6 +36,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
 static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
 {
 	unsigned long gap = rlim_stack->rlim_cur;
+	unsigned long pad = stack_guard_gap;
+
+	/* Account for stack randomization if necessary */
+	if (current->flags & PF_RANDOMIZE)
+		pad += (STACK_RND_MASK << PAGE_SHIFT);
+
+	/* Values close to RLIM_INFINITY can overflow. */
+	if (gap + pad > gap)
+		gap += pad;
 
 	if (gap < MIN_GAP)
 		gap = MIN_GAP;
-- 
2.20.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ