| Message ID | 20220706082016.2603916-3-chao.p.peng@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: mm: fd-based approach for supporting KVM guest private memory | expand |
On 06.07.22 10:20, Chao Peng wrote: > Add tests to verify sealing memfds with the F_SEAL_AUTO_ALLOCATE works > as expected. > > Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> > --- > tools/testing/selftests/memfd/memfd_test.c | 166 +++++++++++++++++++++ > 1 file changed, 166 insertions(+) > > diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c > index 94df2692e6e4..b849ece295fd 100644 > --- a/tools/testing/selftests/memfd/memfd_test.c > +++ b/tools/testing/selftests/memfd/memfd_test.c > @@ -9,6 +9,7 @@ > #include <fcntl.h> > #include <linux/memfd.h> > #include <sched.h> > +#include <setjmp.h> > #include <stdio.h> > #include <stdlib.h> > #include <signal.h> > @@ -232,6 +233,31 @@ static void mfd_fail_open(int fd, int flags, mode_t mode) > } > } > > +static void mfd_assert_fallocate(int fd) > +{ > + int r; > + > + r = fallocate(fd, 0, 0, mfd_def_size); > + if (r < 0) { > + printf("fallocate(ALLOC) failed: %m\n"); > + abort(); > + } > +} > + > +static void mfd_assert_punch_hole(int fd) > +{ > + int r; > + > + r = fallocate(fd, > + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, > + 0, > + mfd_def_size); > + if (r < 0) { > + printf("fallocate(PUNCH_HOLE) failed: %m\n"); > + abort(); > + } > +} > + > static void mfd_assert_read(int fd) > { > char buf[16]; > @@ -594,6 +620,94 @@ static void mfd_fail_grow_write(int fd) > } > } > > +static void mfd_assert_hole_write(int fd) > +{ > + ssize_t l; > + void *p; > + char *p1; > + > + /* > + * huegtlbfs does not support write, but we want to > + * verify everything else here. > + */ > + if (!hugetlbfs_test) { > + /* verify direct write() succeeds */ > + l = write(fd, "\0\0\0\0", 4); > + if (l != 4) { > + printf("write() failed: %m\n"); > + abort(); > + } > + } > + > + /* verify mmaped write succeeds */ > + p = mmap(NULL, > + mfd_def_size, > + PROT_READ | PROT_WRITE, > + MAP_SHARED, > + fd, > + 0); > + if (p == MAP_FAILED) { > + printf("mmap() failed: %m\n"); > + abort(); > + } > + p1 = (char *)p + mfd_def_size - 1; > + *p1 = 'H'; > + if (*p1 != 'H') { > + printf("mmaped write failed: %m\n"); > + abort(); > + > + } > + munmap(p, mfd_def_size); > +} > + > +sigjmp_buf jbuf, *sigbuf; > +static void sig_handler(int sig, siginfo_t *siginfo, void *ptr) > +{ > + if (sig == SIGBUS) { > + if (sigbuf) > + siglongjmp(*sigbuf, 1); > + abort(); > + } > +} > + > +static void mfd_fail_hole_write(int fd) > +{ > + ssize_t l; > + void *p; > + char *p1; > + > + /* verify direct write() fails */ > + l = write(fd, "data", 4); > + if (l > 0) { > + printf("expected failure on write(), but got %d: %m\n", (int)l); > + abort(); > + } > + > + /* verify mmaped write fails */ > + p = mmap(NULL, > + mfd_def_size, > + PROT_READ | PROT_WRITE, > + MAP_SHARED, > + fd, > + 0); > + if (p == MAP_FAILED) { > + printf("mmap() failed: %m\n"); > + abort(); > + } > + > + sigbuf = &jbuf; > + if (sigsetjmp(*sigbuf, 1)) > + goto out; > + > + /* Below write should trigger SIGBUS signal */ > + p1 = (char *)p + mfd_def_size - 1; > + *p1 = 'H'; Maybe you want to verify separately, that bothj > + printf("failed to receive SIGBUS for mmaped write: %m\n"); > + abort(); > +out: > + munmap(p, mfd_def_size); > +} > + > static int idle_thread_fn(void *arg) > { > sigset_t set; > @@ -880,6 +994,57 @@ static void test_seal_resize(void) > close(fd); > } > > +/* > + * Test F_SEAL_AUTO_ALLOCATE > + * Test whether F_SEAL_AUTO_ALLOCATE actually prevents allocation. > + */ > +static void test_seal_auto_allocate(void) > +{ > + struct sigaction act; > + int fd; > + > + printf("%s SEAL-AUTO-ALLOCATE\n", memfd_str); > + > + memset(&act, 0, sizeof(act)); > + act.sa_sigaction = sig_handler; > + act.sa_flags = SA_SIGINFO; > + if (sigaction(SIGBUS, &act, 0)) { > + printf("sigaction() failed: %m\n"); > + abort(); > + } > + > + fd = mfd_assert_new("kern_memfd_seal_auto_allocate", > + mfd_def_size, > + MFD_CLOEXEC | MFD_ALLOW_SEALING); > + > + /* read/write should pass if F_SEAL_AUTO_ALLOCATE not set */ > + mfd_assert_read(fd); > + mfd_assert_hole_write(fd); > + > + mfd_assert_has_seals(fd, 0); > + mfd_assert_add_seals(fd, F_SEAL_AUTO_ALLOCATE); > + mfd_assert_has_seals(fd, F_SEAL_AUTO_ALLOCATE); > + > + /* read/write should pass for pre-allocated area */ > + mfd_assert_read(fd); > + mfd_assert_hole_write(fd); > + > + mfd_assert_punch_hole(fd); > + > + /* read should pass, write should fail in hole */ > + mfd_assert_read(fd); > + mfd_fail_hole_write(fd); > + > + mfd_assert_fallocate(fd); > + > + /* read/write should pass after fallocate */ > + mfd_assert_read(fd); > + mfd_assert_hole_write(fd); > + > + close(fd); > +} What might make sense is to verify for the following operations: * read() * write() * read via mmap * write via mmap After sealing on a hole, that there is *still* a hole and that only the read() might succeed, with a comment stating that shmem optimized for read on holes by reading from the shared zeropage. I'd suggest decoupling hole_write from hole_mmap_write and similarly have hole_read and hole_mmap_read. You should be able to use fstat() to obtain the number of allocated blocks to check that fairly easily.
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 94df2692e6e4..b849ece295fd 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -9,6 +9,7 @@ #include <fcntl.h> #include <linux/memfd.h> #include <sched.h> +#include <setjmp.h> #include <stdio.h> #include <stdlib.h> #include <signal.h> @@ -232,6 +233,31 @@ static void mfd_fail_open(int fd, int flags, mode_t mode) } } +static void mfd_assert_fallocate(int fd) +{ + int r; + + r = fallocate(fd, 0, 0, mfd_def_size); + if (r < 0) { + printf("fallocate(ALLOC) failed: %m\n"); + abort(); + } +} + +static void mfd_assert_punch_hole(int fd) +{ + int r; + + r = fallocate(fd, + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, + 0, + mfd_def_size); + if (r < 0) { + printf("fallocate(PUNCH_HOLE) failed: %m\n"); + abort(); + } +} + static void mfd_assert_read(int fd) { char buf[16]; @@ -594,6 +620,94 @@ static void mfd_fail_grow_write(int fd) } } +static void mfd_assert_hole_write(int fd) +{ + ssize_t l; + void *p; + char *p1; + + /* + * huegtlbfs does not support write, but we want to + * verify everything else here. + */ + if (!hugetlbfs_test) { + /* verify direct write() succeeds */ + l = write(fd, "\0\0\0\0", 4); + if (l != 4) { + printf("write() failed: %m\n"); + abort(); + } + } + + /* verify mmaped write succeeds */ + p = mmap(NULL, + mfd_def_size, + PROT_READ | PROT_WRITE, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + p1 = (char *)p + mfd_def_size - 1; + *p1 = 'H'; + if (*p1 != 'H') { + printf("mmaped write failed: %m\n"); + abort(); + + } + munmap(p, mfd_def_size); +} + +sigjmp_buf jbuf, *sigbuf; +static void sig_handler(int sig, siginfo_t *siginfo, void *ptr) +{ + if (sig == SIGBUS) { + if (sigbuf) + siglongjmp(*sigbuf, 1); + abort(); + } +} + +static void mfd_fail_hole_write(int fd) +{ + ssize_t l; + void *p; + char *p1; + + /* verify direct write() fails */ + l = write(fd, "data", 4); + if (l > 0) { + printf("expected failure on write(), but got %d: %m\n", (int)l); + abort(); + } + + /* verify mmaped write fails */ + p = mmap(NULL, + mfd_def_size, + PROT_READ | PROT_WRITE, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + + sigbuf = &jbuf; + if (sigsetjmp(*sigbuf, 1)) + goto out; + + /* Below write should trigger SIGBUS signal */ + p1 = (char *)p + mfd_def_size - 1; + *p1 = 'H'; + printf("failed to receive SIGBUS for mmaped write: %m\n"); + abort(); +out: + munmap(p, mfd_def_size); +} + static int idle_thread_fn(void *arg) { sigset_t set; @@ -880,6 +994,57 @@ static void test_seal_resize(void) close(fd); } +/* + * Test F_SEAL_AUTO_ALLOCATE + * Test whether F_SEAL_AUTO_ALLOCATE actually prevents allocation. + */ +static void test_seal_auto_allocate(void) +{ + struct sigaction act; + int fd; + + printf("%s SEAL-AUTO-ALLOCATE\n", memfd_str); + + memset(&act, 0, sizeof(act)); + act.sa_sigaction = sig_handler; + act.sa_flags = SA_SIGINFO; + if (sigaction(SIGBUS, &act, 0)) { + printf("sigaction() failed: %m\n"); + abort(); + } + + fd = mfd_assert_new("kern_memfd_seal_auto_allocate", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + /* read/write should pass if F_SEAL_AUTO_ALLOCATE not set */ + mfd_assert_read(fd); + mfd_assert_hole_write(fd); + + mfd_assert_has_seals(fd, 0); + mfd_assert_add_seals(fd, F_SEAL_AUTO_ALLOCATE); + mfd_assert_has_seals(fd, F_SEAL_AUTO_ALLOCATE); + + /* read/write should pass for pre-allocated area */ + mfd_assert_read(fd); + mfd_assert_hole_write(fd); + + mfd_assert_punch_hole(fd); + + /* read should pass, write should fail in hole */ + mfd_assert_read(fd); + mfd_fail_hole_write(fd); + + mfd_assert_fallocate(fd); + + /* read/write should pass after fallocate */ + mfd_assert_read(fd); + mfd_assert_hole_write(fd); + + close(fd); +} + + /* * Test sharing via dup() * Test that seals are shared between dupped FDs and they're all equal. @@ -1059,6 +1224,7 @@ int main(int argc, char **argv) test_seal_shrink(); test_seal_grow(); test_seal_resize(); + test_seal_auto_allocate(); test_share_dup("SHARE-DUP", ""); test_share_mmap("SHARE-MMAP", "");
Add tests to verify sealing memfds with the F_SEAL_AUTO_ALLOCATE works as expected. Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> --- tools/testing/selftests/memfd/memfd_test.c | 166 +++++++++++++++++++++ 1 file changed, 166 insertions(+)