| 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
| ||
|
Message-ID: <20250730005818.2793577-3-isaacmanjarres@google.com>
Date: Tue, 29 Jul 2025 17:58:07 -0700
From: "Isaac J. Manjarres" <isaacmanjarres@...gle.com>
To: lorenzo.stoakes@...cle.com, gregkh@...uxfoundation.org,
Muchun Song <muchun.song@...ux.dev>, Oscar Salvador <osalvador@...e.de>,
David Hildenbrand <david@...hat.com>, Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
Andrew Morton <akpm@...ux-foundation.org>, "Liam R. Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>, Mike Rapoport <rppt@...nel.org>, Suren Baghdasaryan <surenb@...gle.com>,
Michal Hocko <mhocko@...e.com>, Kees Cook <kees@...nel.org>, Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Valentin Schneider <vschneid@...hat.com>, "Matthew Wilcox (Oracle)" <willy@...radead.org>, Jann Horn <jannh@...gle.com>,
Pedro Falcato <pfalcato@...e.de>, Hugh Dickins <hughd@...gle.com>,
Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: aliceryhl@...gle.com, stable@...r.kernel.org,
"Isaac J. Manjarres" <isaacmanjarres@...gle.com>, kernel-team@...roid.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
Lorenzo Stoakes <lstoakes@...il.com>, Andy Lutomirski <luto@...nel.org>,
Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH 5.4.y 2/3] mm: update memfd seal write check to include F_SEAL_WRITE
From: Lorenzo Stoakes <lstoakes@...il.com>
[ Upstream commit 28464bbb2ddc199433383994bcb9600c8034afa1 ]
The seal_check_future_write() function is called by shmem_mmap() or
hugetlbfs_file_mmap() to disallow any future writable mappings of an memfd
sealed this way.
The F_SEAL_WRITE flag is not checked here, as that is handled via the
mapping->i_mmap_writable mechanism and so any attempt at a mapping would
fail before this could be run.
However we intend to change this, meaning this check can be performed for
F_SEAL_WRITE mappings also.
The logic here is equally applicable to both flags, so update this
function to accommodate both and rename it accordingly.
Link: https://lkml.kernel.org/r/913628168ce6cce77df7d13a63970bae06a526e0.1697116581.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com>
Reviewed-by: Jan Kara <jack@...e.cz>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Christian Brauner <brauner@...nel.org>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Matthew Wilcox (Oracle) <willy@...radead.org>
Cc: Mike Kravetz <mike.kravetz@...cle.com>
Cc: Muchun Song <muchun.song@...ux.dev>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Cc: stable@...r.kernel.org
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@...gle.com>
---
fs/hugetlbfs/inode.c | 2 +-
include/linux/mm.h | 15 ++++++++-------
mm/shmem.c | 2 +-
3 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 47b292f9b4f8..c18a47a86e8b 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -152,7 +152,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
vma->vm_ops = &hugetlb_vm_ops;
- ret = seal_check_future_write(info->seals, vma);
+ ret = seal_check_write(info->seals, vma);
if (ret)
return ret;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 47d56c96447a..57cba6e4fdcd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2946,25 +2946,26 @@ static inline int pages_identical(struct page *page1, struct page *page2)
}
/**
- * seal_check_future_write - Check for F_SEAL_FUTURE_WRITE flag and handle it
+ * seal_check_write - Check for F_SEAL_WRITE or F_SEAL_FUTURE_WRITE flags and
+ * handle them.
* @seals: the seals to check
* @vma: the vma to operate on
*
- * Check whether F_SEAL_FUTURE_WRITE is set; if so, do proper check/handling on
- * the vma flags. Return 0 if check pass, or <0 for errors.
+ * Check whether F_SEAL_WRITE or F_SEAL_FUTURE_WRITE are set; if so, do proper
+ * check/handling on the vma flags. Return 0 if check pass, or <0 for errors.
*/
-static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
+static inline int seal_check_write(int seals, struct vm_area_struct *vma)
{
- if (seals & F_SEAL_FUTURE_WRITE) {
+ if (seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
/*
* New PROT_WRITE and MAP_SHARED mmaps are not allowed when
- * "future write" seal active.
+ * write seals are active.
*/
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
return -EPERM;
/*
- * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
+ * Since an F_SEAL_[FUTURE_]WRITE sealed memfd can be mapped as
* MAP_SHARED and read-only, take care to not allow mprotect to
* revert protections on such mappings. Do this only for shared
* mappings. For private mappings, don't need to mask
diff --git a/mm/shmem.c b/mm/shmem.c
index 264229680ad7..8475d56f5977 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2215,7 +2215,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
struct shmem_inode_info *info = SHMEM_I(file_inode(file));
int ret;
- ret = seal_check_future_write(info->seals, vma);
+ ret = seal_check_write(info->seals, vma);
if (ret)
return ret;
--
2.50.1.552.g942d659e1b-goog
Powered by blists - more mailing lists