linux-kernel - [PATCH 1/4] arm64: module: create module allocations without exec permissions

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Date:   Thu, 23 May 2019 11:22:53 +0100
From:   Ard Biesheuvel <ard.biesheuvel@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     marc.zyngier@....com, mark.rutland@....com,
        linux-kernel@...r.kernel.org,
        Ard Biesheuvel <ard.biesheuvel@....com>,
        Nadav Amit <namit@...are.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Will Deacon <will.deacon@....com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        James Morse <james.morse@....com>
Subject: [PATCH 1/4] arm64: module: create module allocations without exec permissions

Now that the core code manages the executable permissions of code
regions of modules explicitly, it is no longer necessary to create
the module vmalloc regions with RWX permissions, and we can create
them with RW- permissions instead, which is preferred from a
security perspective.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@....com>
---
 arch/arm64/kernel/module.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index 2e4e3915b4d0..88f0ed31d9aa 100644
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -41,7 +41,7 @@ void *module_alloc(unsigned long size)
 
 	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
 				module_alloc_base + MODULES_VSIZE,
-				gfp_mask, PAGE_KERNEL_EXEC, 0,
+				gfp_mask, PAGE_KERNEL, 0,
 				NUMA_NO_NODE, __builtin_return_address(0));
 
 	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
@@ -57,7 +57,7 @@ void *module_alloc(unsigned long size)
 		 */
 		p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
 				module_alloc_base + SZ_4G, GFP_KERNEL,
-				PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+				PAGE_KERNEL, 0, NUMA_NO_NODE,
 				__builtin_return_address(0));
 
 	if (p && (kasan_module_alloc(p, size) < 0)) {
-- 
2.17.1