linux-kernel - [PATCH v1 3/3] mm: ignore MAP_EXECUTABLE in ksys_mmap

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

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210421093453.6904-4-david@redhat.com>
Date:   Wed, 21 Apr 2021 11:34:53 +0200
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     David Hildenbrand <david@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Peter Zijlstra <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Mike Rapoport <rppt@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Kevin Brodsky <Kevin.Brodsky@....com>,
        Michal Hocko <mhocko@...e.com>,
        Feng Tang <feng.tang@...el.com>,
        Don Zickus <dzickus@...hat.com>, x86@...nel.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v1 3/3] mm: ignore MAP_EXECUTABLE in ksys_mmap_pgoff()

Let's also remove masking off MAP_EXECUTABLE from ksys_mmap_pgoff():
the last in-tree occurrence of MAP_EXECUTABLE 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_EXECUTABLE is ignored.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 include/linux/mman.h | 2 ++
 mm/mmap.c            | 2 +-
 mm/nommu.c           | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/mman.h b/include/linux/mman.h
index 629cefc4ecba..ebb09a964272 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -31,6 +31,8 @@
 /*
  * 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.
  */
 #define LEGACY_MAP_MASK (MAP_SHARED \
 		| MAP_PRIVATE \
diff --git a/mm/mmap.c b/mm/mmap.c
index 3f287599a7a3..882f8ee4af1f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1627,7 +1627,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 			return PTR_ERR(file);
 	}
 
-	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+	flags &= ~MAP_DENYWRITE;
 
 	retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
 out_fput:
diff --git a/mm/nommu.c b/mm/nommu.c
index 5c9ab799c0e6..1fafe3e9d3df 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1306,7 +1306,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 			goto out;
 	}
 
-	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
+	flags &= ~MAP_DENYWRITE;
 
 	retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
 
-- 
2.30.2