linux-kernel - [RFC PATCH 2/6] [ARM] mm/mmap.c: Check length of unmapped area before allowing MAP

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:   Mon, 6 Dec 2021 15:02:52 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     Liam Howlett <liam.howlett@...cle.com>,
        Russell King <linux@...linux.org.uk>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH 2/6] [ARM] mm/mmap.c: Check length of unmapped area before
 allowing MAP_FIXED

arch_get_unmapped_area() could potentially allow a larger than possible
length when using the MAP_FIXED flag.  The bound check should come
before the check for MAP_FIXED.

Fixes: 4fbe66759b2a ([ARM] Fix shared mmap()ings for ARM VIPT caches.)
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 arch/arm/mm/mmap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index a0f8a0ca0788..cb135556ce36 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -36,6 +36,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	int aliasing = cache_is_vipt_aliasing();
 	struct vm_unmapped_area_info info;
 
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
 	/*
 	 * We only need to do colour alignment if either the I or D
 	 * caches alias.
@@ -53,9 +56,6 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		return addr;
 	}
 
-	if (len > TASK_SIZE)
-		return -ENOMEM;
-
 	if (addr) {
 		if (do_align)
 			addr = COLOUR_ALIGN(addr, pgoff);
-- 
2.30.2