From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C826273DBB; Sun, 24 Mar 2024 23:35:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323332; cv=none; b=BUlBQj+lIqaFUe8dOIiZfv9Zi1WNyi2rqsuj01N7gZMhqJvXtzTzTP36Dx5TuOlT7kdtXq7a+SYCb0hMjX2aU1QFzNOQW2VyHUsWq9hEqVYjHJGDub8C9vJ3K3AQPVhi9F/JpTgvsKIc49n8Ll9H+gxFzsRzs1B/mAfIzJsR02U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323332; c=relaxed/simple; bh=6p7GtlaV3i7BYeRheWHSBY+UMq556/KqSfeQ7J31cXQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YAk4Nhr8LuMh3lFOIseM7xxeP9QWYBokTZVSUVdr9GOkMR4gDI2chj33qjDxFXxK8f7QjqxXyEhYvKx+GIRYv2S1xm/eBapjBL8a6VYZTZHQu4ky4r0TDAObdoa+9pQQg9OKFkpsA5iqkfkLtkuyg/yt/6m/q1p2+U+zBGPS1QE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IdRJcqiW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IdRJcqiW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F149BC3277D; Sun, 24 Mar 2024 23:35:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711323330; bh=6p7GtlaV3i7BYeRheWHSBY+UMq556/KqSfeQ7J31cXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IdRJcqiWy6UsnxLPkBeN33c9l+l10a2ahaO1CJmqzZ8ApebmgY5cFumCZNIjfk+2Z 7ZPpID3Gc1aQ53SXBWt/p264DAmt+aN/9FB82Zp8amJ+icDp56buQ0CXyK3w8D+dlN TRDX6LGPW7ZZISErlXGXjMlhgTPJKxd9keG7mOlM30fFrKPJrstzzVokw0WZ0eStLO vW2FrxNyidyyzrPsoYJuHT1gvI5vQPwrR38G7Gt7r8Kr4wylyTHsJ5hateVaapoWlg VqC0cK5ah9dmIxv3UYPQb19zUnhL24avS+rvbhkLCCRNARhj/SQJMgG35B9iDerhiV JgotoCfkWwmjQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nikita Zhandarovich , Chuck Lever III , syzbot+09b349b3066c2e0b1e96@syzkaller.appspotmail.com, Jan Kara , Christian Brauner , Sasha Levin Subject: [PATCH 5.15 031/317] do_sys_name_to_handle(): use kzalloc() to fix kernel-infoleak Date: Sun, 24 Mar 2024 19:30:11 -0400 Message-ID: <20240324233458.1352854-32-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324233458.1352854-1-sashal@kernel.org> References: <20240324233458.1352854-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Nikita Zhandarovich [ Upstream commit 3948abaa4e2be938ccdfc289385a27342fb13d43 ] syzbot identified a kernel information leak vulnerability in do_sys_name_to_handle() and issued the following report [1]. [1] "BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x100 lib/usercopy.c:40 instrument_copy_to_user include/linux/instrumented.h:114 [inline] _copy_to_user+0xbc/0x100 lib/usercopy.c:40 copy_to_user include/linux/uaccess.h:191 [inline] do_sys_name_to_handle fs/fhandle.c:73 [inline] __do_sys_name_to_handle_at fs/fhandle.c:112 [inline] __se_sys_name_to_handle_at+0x949/0xb10 fs/fhandle.c:94 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94 ... Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] __kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc+0x121/0x3c0 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] do_sys_name_to_handle fs/fhandle.c:39 [inline] __do_sys_name_to_handle_at fs/fhandle.c:112 [inline] __se_sys_name_to_handle_at+0x441/0xb10 fs/fhandle.c:94 __x64_sys_name_to_handle_at+0xe4/0x140 fs/fhandle.c:94 ... Bytes 18-19 of 20 are uninitialized Memory access of size 20 starts at ffff888128a46380 Data copied to user address 0000000020000240" Per Chuck Lever's suggestion, use kzalloc() instead of kmalloc() to solve the problem. Fixes: 990d6c2d7aee ("vfs: Add name to file handle conversion support") Suggested-by: Chuck Lever III Reported-and-tested-by: Signed-off-by: Nikita Zhandarovich Link: https://lore.kernel.org/r/20240119153906.4367-1-n.zhandarovich@fintech.ru Reviewed-by: Jan Kara Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/fhandle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fhandle.c b/fs/fhandle.c index 6630c69c23a2a..55e5ffacc0e40 100644 --- a/fs/fhandle.c +++ b/fs/fhandle.c @@ -37,7 +37,7 @@ static long do_sys_name_to_handle(struct path *path, if (f_handle.handle_bytes > MAX_HANDLE_SZ) return -EINVAL; - handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes, + handle = kzalloc(sizeof(struct file_handle) + f_handle.handle_bytes, GFP_KERNEL); if (!handle) return -ENOMEM; -- 2.43.0