linux-kernel - [PATCH v2 1/2] fs/procfs: fix integer to pointer cast warning in do_procmap

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Message-ID: <20240701174805.1897344-1-andrii@kernel.org>
Date: Mon,  1 Jul 2024 10:48:04 -0700
From: Andrii Nakryiko <andrii@...nel.org>
To: linux-mm@...ck.org,
	akpm@...ux-foundation.org
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	adobriyan@...il.com,
	Andrii Nakryiko <andrii@...nel.org>,
	Arnd Bergmann <arnd@...db.de>,
	Stephen Rothwell <sfr@...b.auug.org.au>
Subject: [PATCH v2 1/2] fs/procfs: fix integer to pointer cast warning in do_procmap_query()

On 32-bit architectures compiler will complain about casting __u64 to
void * pointer:

fs/proc/task_mmu.c: In function 'do_procmap_query':
fs/proc/task_mmu.c:598:48: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  598 |         if (karg.vma_name_size && copy_to_user((void __user *)karg.vma_name_addr,
      |                                                ^
fs/proc/task_mmu.c:605:48: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  605 |         if (karg.build_id_size && copy_to_user((void __user *)karg.build_id_addr,
      |                                                ^

Fix this by using u64_to_user_ptr() helper that's meant to handle this
properly.

Suggested-by: Arnd Bergmann <arnd@...db.de>
Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
Fixes: df789ce1eb90 ("fs/procfs: add build ID fetching to PROCMAP_QUERY API")
Fixes: 3757be498749 ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
Signed-off-by: Andrii Nakryiko <andrii@...nel.org>
---
 fs/proc/task_mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index d99a390a0f41..3f1d0d2f78fe 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -595,14 +595,14 @@ static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
 	query_vma_teardown(mm, vma);
 	mmput(mm);
 
-	if (karg.vma_name_size && copy_to_user((void __user *)karg.vma_name_addr,
+	if (karg.vma_name_size && copy_to_user(u64_to_user_ptr(karg.vma_name_addr),
 					       name, karg.vma_name_size)) {
 		kfree(name_buf);
 		return -EFAULT;
 	}
 	kfree(name_buf);
 
-	if (karg.build_id_size && copy_to_user((void __user *)karg.build_id_addr,
+	if (karg.build_id_size && copy_to_user(u64_to_user_ptr(karg.build_id_addr),
 					       build_id_buf, karg.build_id_size))
 		return -EFAULT;
 
-- 
2.43.0