linux-kernel - [PATCH] arm64: pageattr: Explicitly bail out when changing permissions for vmalloc

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-next>] [day] [month] [year] [list]

Message-Id: <20250328062103.79462-1-dev.jain@arm.com>
Date: Fri, 28 Mar 2025 11:51:03 +0530
From: Dev Jain <dev.jain@....com>
To: catalin.marinas@....com,
	will@...nel.org
Cc: gshan@...hat.com,
	rppt@...nel.org,
	steven.price@....com,
	suzuki.poulose@....com,
	tianyaxiong@...inos.cn,
	ardb@...nel.org,
	david@...hat.com,
	ryan.roberts@....com,
	urezki@...il.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Dev Jain <dev.jain@....com>
Subject: [PATCH] arm64: pageattr: Explicitly bail out when changing permissions for vmalloc_huge mappings

arm64 uses apply_to_page_range to change permissions for kernel VA mappings,
which does not support changing permissions for leaf mappings. This function
will change permissions until it encounters a leaf mapping, and will bail
out. To avoid this partial change, explicitly disallow changing permissions
for VM_ALLOW_HUGE_VMAP mappings.

Signed-off-by: Dev Jain <dev.jain@....com>
---
 arch/arm64/mm/pageattr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 39fd1f7ff02a..8337c88eec69 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -96,7 +96,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 	 * we are operating on does not result in such splitting.
 	 *
 	 * Let's restrict ourselves to mappings created by vmalloc (or vmap).
-	 * Those are guaranteed to consist entirely of page mappings, and
+	 * Disallow VM_ALLOW_HUGE_VMAP vmalloc mappings so that
 	 * splitting is never needed.
 	 *
 	 * So check whether the [addr, addr + size) interval is entirely
@@ -105,7 +105,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 	area = find_vm_area((void *)addr);
 	if (!area ||
 	    end > (unsigned long)kasan_reset_tag(area->addr) + area->size ||
-	    !(area->flags & VM_ALLOC))
+	    ((area->flags & (VM_ALLOC | VM_ALLOW_HUGE_VMAP)) != VM_ALLOC))
 		return -EINVAL;
 
 	if (!numpages)
-- 
2.30.2