linux-kernel - [PATCH 3.18 05/27] ARC: mm: allow mprotect to make stack mappings executable

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: <20180727102649.240963789@linuxfoundation.org>
Date:   Fri, 27 Jul 2018 12:26:42 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vineet Gupta <vgupta@...opsys.com>
Subject: [PATCH 3.18 05/27] ARC: mm: allow mprotect to make stack mappings executable

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Vineet Gupta <vgupta@...opsys.com>

commit 93312b6da4df31e4102ce5420e6217135a16c7ea upstream.

mprotect(EXEC) was failing for stack mappings as default vm flags was
missing MAYEXEC.

This was triggered by glibc test suite nptl/tst-execstack testcase

What is surprising is that despite running LTP for years on, we didn't
catch this issue as it lacks a directed test case.

gcc dejagnu tests with nested functions also requiring exec stack work
fine though because they rely on the GNU_STACK segment spit out by
compiler and handled in kernel elf loader.

This glibc case is different as the stack is non exec to begin with and
a dlopen of shared lib with GNU_STACK segment triggers the exec stack
proceedings using a mprotect(PROT_EXEC) which was broken.

CC: stable@...r.kernel.org
Signed-off-by: Vineet Gupta <vgupta@...opsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arc/include/asm/page.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -97,7 +97,7 @@ typedef unsigned long pgtable_t;
 #define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)

 /* Default Permissions for stack/heaps pages (Non Executable) */
-#define VM_DATA_DEFAULT_FLAGS   (VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE)
+#define VM_DATA_DEFAULT_FLAGS   (VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)

 #define WANT_PAGE_VIRTUAL   1