The patch titled
Subject: selftests/memfd: add test for mapping write-sealed memfd read-only
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
selftests-memfd-add-test-for-mapping-write-sealed-memfd-read-only.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-memfd-add-test-for-mapping-write-sealed-memfd-read-only.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Subject: selftests/memfd: add test for mapping write-sealed memfd read-only
Date: Thu, 28 Nov 2024 15:06:18 +0000
Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only,
assert that we are able to do this in a test to ensure that we do not
regress this again.
Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.1732804776.git.lorenzo.stoakes@xxxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Julian Orth <ju.orth@xxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/memfd/memfd_test.c | 43 +++++++++++++++++++
1 file changed, 43 insertions(+)
--- a/tools/testing/selftests/memfd/memfd_test.c~selftests-memfd-add-test-for-mapping-write-sealed-memfd-read-only
+++ a/tools/testing/selftests/memfd/memfd_test.c
@@ -281,6 +281,24 @@ static void *mfd_assert_mmap_shared(int
return p;
}
+static void *mfd_assert_mmap_read_shared(int fd)
+{
+ void *p;
+
+ p = mmap(NULL,
+ mfd_def_size,
+ PROT_READ,
+ MAP_SHARED,
+ fd,
+ 0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+
+ return p;
+}
+
static void *mfd_assert_mmap_private(int fd)
{
void *p;
@@ -979,6 +997,30 @@ static void test_seal_future_write(void)
close(fd);
}
+static void test_seal_write_map_read_shared(void)
+{
+ int fd;
+ void *p;
+
+ printf("%s SEAL-WRITE-MAP-READ\n", memfd_str);
+
+ fd = mfd_assert_new("kern_memfd_seal_write_map_read",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ mfd_assert_add_seals(fd, F_SEAL_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_WRITE);
+
+ p = mfd_assert_mmap_read_shared(fd);
+
+ mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
+ mfd_fail_write(fd);
+
+ munmap(p, mfd_def_size);
+ close(fd);
+}
+
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
@@ -1587,6 +1629,7 @@ int main(int argc, char **argv)
test_seal_write();
test_seal_future_write();
+ test_seal_write_map_read_shared();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
_
Patches currently in -mm which might be from lorenzo.stoakes@xxxxxxxxxx are
mm-reinstate-ability-to-map-write-sealed-memfd-mappings-read-only.patch
selftests-memfd-add-test-for-mapping-write-sealed-memfd-read-only.patch
docs-mm-add-vma-locks-documentation.patch
docs-mm-add-vma-locks-documentation-v3.patch
docs-mm-add-vma-locks-documentation-fix.patch
