linux-hardening - [PATCH v1 1/2] mseal: fix mmap(FIXED) error code.

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Message-ID: <20240828225522.684774-1-jeffxu@chromium.org>
Date: Wed, 28 Aug 2024 22:55:21 +0000
From: jeffxu@...omium.org
To: akpm@...ux-foundation.org
Cc: linux-kselftest@...r.kernel.org,
	linux-mm@...ck.org,
	linux-hardening@...r.kernel.org,
	pedro.falcato@...il.com,
	rientjes@...gle.com,
	keescook@...omium.org,
	Jeff Xu <jeffxu@...omium.org>
Subject: [PATCH v1 1/2] mseal: fix mmap(FIXED) error code.

From: Jeff Xu <jeffxu@...omium.org>

mmap(MAP_FIXED) should return EPERM when memory is sealed.

Fixes: 4205a39e06da ("mm/munmap: replace can_modify_mm with can_modify_vma")
Signed-off-by: Jeff Xu <jeffxu@...omium.org>
---
 mm/mmap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 80d70ed099cf..0cd0c0ef03c7 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1386,7 +1386,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 		mt_on_stack(mt_detach);
 		mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
 		/* Prepare to unmap any existing mapping in the area */
-		if (vms_gather_munmap_vmas(&vms, &mas_detach))
+		error = vms_gather_munmap_vmas(&vms, &mas_detach);
+		if (error == -EPERM)
+			return -EPERM;
+		if (error)
 			return -ENOMEM;
 
 		vmg.next = vms.next;
-- 
2.46.0.295.g3b9ea8a38a-goog