[v1,3/3] mm: ignore MAP_EXECUTABLE in ksys_mmap_pgoff()

Commit Message

David Hildenbrand April 21, 2021, 9:34 a.m. UTC

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 <[e-mail]>
---
 include/linux/mman.h | 2 ++
 mm/mmap.c            | 2 +-
 mm/nommu.c           | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

Patch

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);