Commit de1b2a20 authored by Audra Mitchell's avatar Audra Mitchell Committed by Yongqiang Liu
Browse files

Fix userfaultfd_api to return EINVAL as expected 

mainline inclusion
from mainline-v6.10
commit 1723f04caacb32cadc4e063725d836a0c4450694
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEN5
CVE: CVE-2024-41027

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1723f04caacb32cadc4e063725d836a0c4450694

--------------------------------

Currently if we request a feature that is not set in the Kernel config we
fail silently and return all the available features.  However, the man
page indicates we should return an EINVAL.

We need to fix this issue since we can end up with a Kernel warning should
a program request the feature UFFD_FEATURE_WP_UNPOPULATED on a kernel with
the config not set with this feature.

 [  200.812896] WARNING: CPU: 91 PID: 13634 at mm/memory.c:1660 zap_pte_range+0x43d/0x660
 [  200.820738] Modules linked in:
 [  200.869387] CPU: 91 PID: 13634 Comm: userfaultfd Kdump: loaded Not tainted 6.9.0-rc5+ #8
 [  200.877477] Hardware name: Dell Inc. PowerEdge R6525/0N7YGH, BIOS 2.7.3 03/30/2022
 [  200.885052] RIP: 0010:zap_pte_range+0x43d/0x660

Link: https://lkml.kernel.org/r/20240626130513.120193-1-audra@redhat.com


Fixes: e06f1e1d ("userfaultfd: wp: enabled write protection in userfaultfd API")
Signed-off-by: default avatarAudra Mitchell <audra@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Conflicts:
	fs/userfaultfd.c
[Yongqiang: Only fix context]
Signed-off-by: default avatarYongqiang Liu <liuyongqiang13@huawei.com>
parent ab54dce9

fs/userfaultfd.c

+6 −1
Original line number Diff line number Diff line
@@ -1884,7 +1884,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, 
		goto out;

	features = uffdio_api.features;

	ret = -EINVAL;

	if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES))

	if (uffdio_api.api != UFFD_API)

		goto err_out;

	ret = -EPERM;

	if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
@@ -1894,6 +1894,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, 
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP

	uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;

#endif



	ret = -EINVAL;

	if (features & ~uffdio_api.features)

		goto err_out;



	uffdio_api.ioctls = UFFD_API_IOCTLS;

	ret = -EFAULT;

	if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))