Re: [PATCH -next 2/2] selftests/memfd: modify tests for F_SEAL_FUTURE_WRITE seal
On Mon, Nov 19, 2018 at 09:21:37PM -0800, Joel Fernandes (Google) wrote:
> Modify the tests for F_SEAL_FUTURE_WRITE based on the changes
> introduced in previous patch.
>
> Also add a test to make sure the reopen issue pointed by Jann Horn [1]
> is fixed.
>
> [1]
> https://lore.kernel.org/lkml/CAG48ez1h=v-JYnDw81HaYJzOfrNhwYksxmc2r=cjvdqvgym...@mail.gmail.com/
>
> Cc: Jann Horn
> Signed-off-by: Joel Fernandes (Google)
> ---
> tools/testing/selftests/memfd/memfd_test.c | 88 +++---
> 1 file changed, 44 insertions(+), 44 deletions(-)
Since we squashed [1] the mm/memfd patch modifications suggested by Andy into
the original patch, I also squashed the selftests modifications and appended
the patch inline below if you want to take this instead:
[1]
https://lore.kernel.org/lkml/20181122230906.ga198...@google.com/T/#m8ba68f67f3ec24913a977b62bcaeafc4b194b8c8
---8<---
From: "Joel Fernandes (Google)"
Subject: [PATCH v4] selftests/memfd: add tests for F_SEAL_FUTURE_WRITE seal
Add tests to verify sealing memfds with the F_SEAL_FUTURE_WRITE works as
expected.
Signed-off-by: Joel Fernandes (Google)
---
tools/testing/selftests/memfd/memfd_test.c | 74 ++
1 file changed, 74 insertions(+)
diff --git a/tools/testing/selftests/memfd/memfd_test.c
b/tools/testing/selftests/memfd/memfd_test.c
index 10baa1652fc2..c67d32eeb668 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -54,6 +54,22 @@ static int mfd_assert_new(const char *name, loff_t sz,
unsigned int flags)
return fd;
}
+static int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, fd;
+ char path[100];
+
+ sprintf(path, "/proc/self/fd/%d", fd_in);
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ printf("re-open of existing fd %d failed\n", fd_in);
+ abort();
+ }
+
+ return fd;
+}
+
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
@@ -255,6 +271,25 @@ static void mfd_assert_read(int fd)
munmap(p, mfd_def_size);
}
+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+ void *p;
+
+ /* verify PROT_READ and MAP_SHARED *is* allowed */
+ p = mmap(NULL,
+mfd_def_size,
+PROT_READ,
+MAP_SHARED,
+fd,
+0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, mfd_def_size);
+}
+
static void mfd_assert_write(int fd)
{
ssize_t l;
@@ -692,6 +727,44 @@ static void test_seal_write(void)
close(fd);
}
+/*
+ * Test SEAL_FUTURE_WRITE
+ * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
+ */
+static void test_seal_future_write(void)
+{
+ int fd, fd2;
+ void *p;
+
+ printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
+
+ fd = mfd_assert_new("kern_memfd_seal_future_write",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ p = mfd_assert_mmap_shared(fd);
+
+ mfd_assert_has_seals(fd, 0);
+
+ mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
+
+ /* read should pass, writes should fail */
+ mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
+ mfd_fail_write(fd);
+
+ fd2 = mfd_assert_reopen_fd(fd);
+ /* read should pass, writes should still fail */
+ mfd_assert_read(fd2);
+ mfd_assert_read_shared(fd2);
+ mfd_fail_write(fd2);
+
+ munmap(p, mfd_def_size);
+ close(fd2);
+ close(fd);
+}
+
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
@@ -945,6 +1018,7 @@ int main(int argc, char **argv)
test_basic();
test_seal_write();
+ test_seal_future_write();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
--
2.19.1.1215.g8438c0b245-goog
Re: [PATCH -next 2/2] selftests/memfd: modify tests for F_SEAL_FUTURE_WRITE seal
On Mon, Nov 19, 2018 at 09:21:37PM -0800, Joel Fernandes (Google) wrote:
> Modify the tests for F_SEAL_FUTURE_WRITE based on the changes
> introduced in previous patch.
>
> Also add a test to make sure the reopen issue pointed by Jann Horn [1]
> is fixed.
>
> [1]
> https://lore.kernel.org/lkml/CAG48ez1h=v-JYnDw81HaYJzOfrNhwYksxmc2r=cjvdqvgym...@mail.gmail.com/
>
> Cc: Jann Horn
> Signed-off-by: Joel Fernandes (Google)
> ---
> tools/testing/selftests/memfd/memfd_test.c | 88 +++---
> 1 file changed, 44 insertions(+), 44 deletions(-)
Since we squashed [1] the mm/memfd patch modifications suggested by Andy into
the original patch, I also squashed the selftests modifications and appended
the patch inline below if you want to take this instead:
[1]
https://lore.kernel.org/lkml/20181122230906.ga198...@google.com/T/#m8ba68f67f3ec24913a977b62bcaeafc4b194b8c8
---8<---
From: "Joel Fernandes (Google)"
Subject: [PATCH v4] selftests/memfd: add tests for F_SEAL_FUTURE_WRITE seal
Add tests to verify sealing memfds with the F_SEAL_FUTURE_WRITE works as
expected.
Signed-off-by: Joel Fernandes (Google)
---
tools/testing/selftests/memfd/memfd_test.c | 74 ++
1 file changed, 74 insertions(+)
diff --git a/tools/testing/selftests/memfd/memfd_test.c
b/tools/testing/selftests/memfd/memfd_test.c
index 10baa1652fc2..c67d32eeb668 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -54,6 +54,22 @@ static int mfd_assert_new(const char *name, loff_t sz,
unsigned int flags)
return fd;
}
+static int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, fd;
+ char path[100];
+
+ sprintf(path, "/proc/self/fd/%d", fd_in);
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ printf("re-open of existing fd %d failed\n", fd_in);
+ abort();
+ }
+
+ return fd;
+}
+
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
@@ -255,6 +271,25 @@ static void mfd_assert_read(int fd)
munmap(p, mfd_def_size);
}
+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+ void *p;
+
+ /* verify PROT_READ and MAP_SHARED *is* allowed */
+ p = mmap(NULL,
+mfd_def_size,
+PROT_READ,
+MAP_SHARED,
+fd,
+0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, mfd_def_size);
+}
+
static void mfd_assert_write(int fd)
{
ssize_t l;
@@ -692,6 +727,44 @@ static void test_seal_write(void)
close(fd);
}
+/*
+ * Test SEAL_FUTURE_WRITE
+ * Test whether SEAL_FUTURE_WRITE actually prevents modifications.
+ */
+static void test_seal_future_write(void)
+{
+ int fd, fd2;
+ void *p;
+
+ printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
+
+ fd = mfd_assert_new("kern_memfd_seal_future_write",
+ mfd_def_size,
+ MFD_CLOEXEC | MFD_ALLOW_SEALING);
+
+ p = mfd_assert_mmap_shared(fd);
+
+ mfd_assert_has_seals(fd, 0);
+
+ mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
+
+ /* read should pass, writes should fail */
+ mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
+ mfd_fail_write(fd);
+
+ fd2 = mfd_assert_reopen_fd(fd);
+ /* read should pass, writes should still fail */
+ mfd_assert_read(fd2);
+ mfd_assert_read_shared(fd2);
+ mfd_fail_write(fd2);
+
+ munmap(p, mfd_def_size);
+ close(fd2);
+ close(fd);
+}
+
/*
* Test SEAL_SHRINK
* Test whether SEAL_SHRINK actually prevents shrinking
@@ -945,6 +1018,7 @@ int main(int argc, char **argv)
test_basic();
test_seal_write();
+ test_seal_future_write();
test_seal_shrink();
test_seal_grow();
test_seal_resize();
--
2.19.1.1215.g8438c0b245-goog
[PATCH -next 2/2] selftests/memfd: modify tests for F_SEAL_FUTURE_WRITE seal
Modify the tests for F_SEAL_FUTURE_WRITE based on the changes
introduced in previous patch.
Also add a test to make sure the reopen issue pointed by Jann Horn [1]
is fixed.
[1]
https://lore.kernel.org/lkml/CAG48ez1h=v-JYnDw81HaYJzOfrNhwYksxmc2r=cjvdqvgym...@mail.gmail.com/
Cc: Jann Horn
Signed-off-by: Joel Fernandes (Google)
---
tools/testing/selftests/memfd/memfd_test.c | 88 +++---
1 file changed, 44 insertions(+), 44 deletions(-)
diff --git a/tools/testing/selftests/memfd/memfd_test.c
b/tools/testing/selftests/memfd/memfd_test.c
index 32b207ca7372..c67d32eeb668 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -54,6 +54,22 @@ static int mfd_assert_new(const char *name, loff_t sz,
unsigned int flags)
return fd;
}
+static int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, fd;
+ char path[100];
+
+ sprintf(path, "/proc/self/fd/%d", fd_in);
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ printf("re-open of existing fd %d failed\n", fd_in);
+ abort();
+ }
+
+ return fd;
+}
+
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
@@ -255,6 +271,25 @@ static void mfd_assert_read(int fd)
munmap(p, mfd_def_size);
}
+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+ void *p;
+
+ /* verify PROT_READ and MAP_SHARED *is* allowed */
+ p = mmap(NULL,
+mfd_def_size,
+PROT_READ,
+MAP_SHARED,
+fd,
+0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, mfd_def_size);
+}
+
static void mfd_assert_write(int fd)
{
ssize_t l;
@@ -698,7 +733,7 @@ static void test_seal_write(void)
*/
static void test_seal_future_write(void)
{
- int fd;
+ int fd, fd2;
void *p;
printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
@@ -710,58 +745,23 @@ static void test_seal_future_write(void)
p = mfd_assert_mmap_shared(fd);
mfd_assert_has_seals(fd, 0);
- /* Not adding grow/shrink seals makes the future write
-* seal fail to get added
-*/
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_GROW);
- mfd_assert_has_seals(fd, F_SEAL_GROW);
-
- /* Should still fail since shrink seal has
-* not yet been added
-*/
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_SHRINK);
- mfd_assert_has_seals(fd, F_SEAL_GROW |
-F_SEAL_SHRINK);
- /* Now should succeed, also verifies that the seal
-* could be added with an existing writable mmap
-*/
mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
/* read should pass, writes should fail */
mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
mfd_fail_write(fd);
- munmap(p, mfd_def_size);
- close(fd);
-
- /* Test adding all seals (grow, shrink, future write) at once */
- fd = mfd_assert_new("kern_memfd_seal_future_write2",
- mfd_def_size,
- MFD_CLOEXEC | MFD_ALLOW_SEALING);
-
- p = mfd_assert_mmap_shared(fd);
-
- mfd_assert_has_seals(fd, 0);
- mfd_assert_add_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
-
- /* read should pass, writes should fail */
- mfd_assert_read(fd);
- mfd_fail_write(fd);
+ fd2 = mfd_assert_reopen_fd(fd);
+ /* read should pass, writes should still fail */
+ mfd_assert_read(fd2);
+ mfd_assert_read_shared(fd2);
+ mfd_fail_write(fd2);
munmap(p, mfd_def_size);
+ close(fd2);
close(fd);
}
--
2.19.1.1215.g8438c0b245-goog
[PATCH -next 2/2] selftests/memfd: modify tests for F_SEAL_FUTURE_WRITE seal
Modify the tests for F_SEAL_FUTURE_WRITE based on the changes
introduced in previous patch.
Also add a test to make sure the reopen issue pointed by Jann Horn [1]
is fixed.
[1]
https://lore.kernel.org/lkml/CAG48ez1h=v-JYnDw81HaYJzOfrNhwYksxmc2r=cjvdqvgym...@mail.gmail.com/
Cc: Jann Horn
Signed-off-by: Joel Fernandes (Google)
---
tools/testing/selftests/memfd/memfd_test.c | 88 +++---
1 file changed, 44 insertions(+), 44 deletions(-)
diff --git a/tools/testing/selftests/memfd/memfd_test.c
b/tools/testing/selftests/memfd/memfd_test.c
index 32b207ca7372..c67d32eeb668 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -54,6 +54,22 @@ static int mfd_assert_new(const char *name, loff_t sz,
unsigned int flags)
return fd;
}
+static int mfd_assert_reopen_fd(int fd_in)
+{
+ int r, fd;
+ char path[100];
+
+ sprintf(path, "/proc/self/fd/%d", fd_in);
+
+ fd = open(path, O_RDWR);
+ if (fd < 0) {
+ printf("re-open of existing fd %d failed\n", fd_in);
+ abort();
+ }
+
+ return fd;
+}
+
static void mfd_fail_new(const char *name, unsigned int flags)
{
int r;
@@ -255,6 +271,25 @@ static void mfd_assert_read(int fd)
munmap(p, mfd_def_size);
}
+/* Test that PROT_READ + MAP_SHARED mappings work. */
+static void mfd_assert_read_shared(int fd)
+{
+ void *p;
+
+ /* verify PROT_READ and MAP_SHARED *is* allowed */
+ p = mmap(NULL,
+mfd_def_size,
+PROT_READ,
+MAP_SHARED,
+fd,
+0);
+ if (p == MAP_FAILED) {
+ printf("mmap() failed: %m\n");
+ abort();
+ }
+ munmap(p, mfd_def_size);
+}
+
static void mfd_assert_write(int fd)
{
ssize_t l;
@@ -698,7 +733,7 @@ static void test_seal_write(void)
*/
static void test_seal_future_write(void)
{
- int fd;
+ int fd, fd2;
void *p;
printf("%s SEAL-FUTURE-WRITE\n", memfd_str);
@@ -710,58 +745,23 @@ static void test_seal_future_write(void)
p = mfd_assert_mmap_shared(fd);
mfd_assert_has_seals(fd, 0);
- /* Not adding grow/shrink seals makes the future write
-* seal fail to get added
-*/
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_GROW);
- mfd_assert_has_seals(fd, F_SEAL_GROW);
-
- /* Should still fail since shrink seal has
-* not yet been added
-*/
- mfd_fail_add_seals(fd, F_SEAL_FUTURE_WRITE);
-
- mfd_assert_add_seals(fd, F_SEAL_SHRINK);
- mfd_assert_has_seals(fd, F_SEAL_GROW |
-F_SEAL_SHRINK);
- /* Now should succeed, also verifies that the seal
-* could be added with an existing writable mmap
-*/
mfd_assert_add_seals(fd, F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
+ mfd_assert_has_seals(fd, F_SEAL_FUTURE_WRITE);
/* read should pass, writes should fail */
mfd_assert_read(fd);
+ mfd_assert_read_shared(fd);
mfd_fail_write(fd);
- munmap(p, mfd_def_size);
- close(fd);
-
- /* Test adding all seals (grow, shrink, future write) at once */
- fd = mfd_assert_new("kern_memfd_seal_future_write2",
- mfd_def_size,
- MFD_CLOEXEC | MFD_ALLOW_SEALING);
-
- p = mfd_assert_mmap_shared(fd);
-
- mfd_assert_has_seals(fd, 0);
- mfd_assert_add_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
- mfd_assert_has_seals(fd, F_SEAL_SHRINK |
-F_SEAL_GROW |
-F_SEAL_FUTURE_WRITE);
-
- /* read should pass, writes should fail */
- mfd_assert_read(fd);
- mfd_fail_write(fd);
+ fd2 = mfd_assert_reopen_fd(fd);
+ /* read should pass, writes should still fail */
+ mfd_assert_read(fd2);
+ mfd_assert_read_shared(fd2);
+ mfd_fail_write(fd2);
munmap(p, mfd_def_size);
+ close(fd2);
close(fd);
}
--
2.19.1.1215.g8438c0b245-goog
