linux-kernel - [PATCH AUTOSEL 4.9 19/30] mm/cma.c: fail if fixed declaration can't be honored

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]

Date:   Fri, 26 Jul 2019 09:44:21 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Doug Berger <opendmb@...il.com>,
        Michal Nazarewicz <mina86@...a86.com>,
        Yue Hu <huyue2@...ong.com>, Mike Rapoport <rppt@...ux.ibm.com>,
        Laura Abbott <labbott@...hat.com>, Peng Fan <peng.fan@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>, linux-mm@...ck.org
Subject: [PATCH AUTOSEL 4.9 19/30] mm/cma.c: fail if fixed declaration can't be honored

From: Doug Berger <opendmb@...il.com>

[ Upstream commit c633324e311243586675e732249339685e5d6faa ]

The description of cma_declare_contiguous() indicates that if the
'fixed' argument is true the reserved contiguous area must be exactly at
the address of the 'base' argument.

However, the function currently allows the 'base', 'size', and 'limit'
arguments to be silently adjusted to meet alignment constraints.  This
commit enforces the documented behavior through explicit checks that
return an error if the region does not fit within a specified region.

Link: http://lkml.kernel.org/r/1561422051-16142-1-git-send-email-opendmb@gmail.com
Fixes: 5ea3b1b2f8ad ("cma: add placement specifier for "cma=" kernel parameter")
Signed-off-by: Doug Berger <opendmb@...il.com>
Acked-by: Michal Nazarewicz <mina86@...a86.com>
Cc: Yue Hu <huyue2@...ong.com>
Cc: Mike Rapoport <rppt@...ux.ibm.com>
Cc: Laura Abbott <labbott@...hat.com>
Cc: Peng Fan <peng.fan@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Andrey Konovalov <andreyknvl@...gle.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>
---
 mm/cma.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/mm/cma.c b/mm/cma.c
index 4ea0f32761c1..7cb569a188c4 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -268,6 +268,12 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	 */
 	alignment = max(alignment,  (phys_addr_t)PAGE_SIZE <<
 			  max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
+	if (fixed && base & (alignment - 1)) {
+		ret = -EINVAL;
+		pr_err("Region at %pa must be aligned to %pa bytes\n",
+			&base, &alignment);
+		goto err;
+	}
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);
@@ -298,6 +304,13 @@ int __init cma_declare_contiguous(phys_addr_t base,
 	if (limit == 0 || limit > memblock_end)
 		limit = memblock_end;
 
+	if (base + size > limit) {
+		ret = -EINVAL;
+		pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
+			&size, &base, &limit);
+		goto err;
+	}
+
 	/* Reserve memory */
 	if (fixed) {
 		if (memblock_is_region_reserved(base, size) ||
-- 
2.20.1