From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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Suren Baghdasaryan <surenb@google.com>,
Shakeel Butt <shakeelb@google.com>,
Marco Elver <elver@google.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Nicolas Viennot <Nicolas.Viennot@twosigma.com>,
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Collin Fijalkovich <cfijalkovich@google.com>,
Michal Hocko <mhocko@suse.com>,
linux-api@vger.kernel.org, x86@kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH RFC 6/7] mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()
Date: Fri, 23 Apr 2021 15:16:39 +0200 [thread overview]
Message-ID: <20210423131640.20080-7-david@redhat.com> (raw)
In-Reply-To: <20210423131640.20080-1-david@redhat.com>
Let's also remove masking off MAP_DENYWROTE from ksys_mmap_pgoff():
the last in-tree occurrence of MAP_DENYWRITE is now in LEGACY_MAP_MASK,
which accepts the flag e.g., for MAP_SHARED_VALIDATE; however, the flag
is ignored throughout the kernel now.
Add a comment to LEGACY_MAP_MASK stating that MAP_DENYWRITE is ignored.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/mman.h | 3 ++-
mm/mmap.c | 2 --
mm/nommu.c | 2 --
3 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/include/linux/mman.h b/include/linux/mman.h
index bd9aadda047b..b66e91b8176c 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -32,7 +32,8 @@
* The historical set of flags that all mmap implementations implicitly
* support when a ->mmap_validate() op is not provided in file_operations.
*
- * MAP_EXECUTABLE is completely ignored throughout the kernel.
+ * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the
+ * kernel.
*/
#define LEGACY_MAP_MASK (MAP_SHARED \
| MAP_PRIVATE \
diff --git a/mm/mmap.c b/mm/mmap.c
index b335f8907568..33479ce05653 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1623,8 +1623,6 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
return PTR_ERR(file);
}
- flags &= ~MAP_DENYWRITE;
-
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
out_fput:
if (file)
diff --git a/mm/nommu.c b/mm/nommu.c
index 1fafe3e9d3df..7d85c8a46582 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1306,8 +1306,6 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
goto out;
}
- flags &= ~MAP_DENYWRITE;
-
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
if (file)
--
2.30.2
next prev parent reply other threads:[~2021-04-23 13:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 13:16 [PATCH RFC 0/7] Remove in-tree usage of MAP_DENYWRITE David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 1/7] binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib() David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 2/7] kernel/fork: factor out atomcially replacing the current MM exe_file David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 3/7] kernel/fork: always deny write access to " David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 4/7] binfmt: remove in-tree usage of MAP_DENYWRITE David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 5/7] mm: remove VM_DENYWRITE David Hildenbrand
2021-04-23 13:16 ` David Hildenbrand [this message]
2021-04-23 13:16 ` [PATCH RFC 7/7] fs: update documentation of get_write_access() and friends David Hildenbrand
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