[LTP] [PATCH v2 1/2] syscalls/fanotify20: add new test for FAN_REPORT_PIDFD

[Matthew Bobrowski via ltp <ltp@lists.linux.it>]

This test ensures that the fanotify API returns the expected error
status code -EINVAL when an invalid flag is supplied alongside the new
FAN_REPORT_PIDFD initialization flag. Currently, FAN_REPORT_TID is the
only initialization flag that is not permitted in conjunction with
FAN_REPORT_PIDFD, so we explicitly provide test coverage for this.

We also add an extra trivial test case to ensure that the
initialization behavior with the other FAN_REPORT_* related flags is
working as intended.

Signed-off-by: Matthew Bobrowski <repnop@google.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
---
Changes since v1:
 - Introduced a new macro
   REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_BY_KERNEL() that is
   responsible for testing whether the supplied initialization flags
   are supported by the underlying kernel. This is used from
   do_setup(). Using this is less ambiguous then using something like
   REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_ON_FS().

 configure.ac                                  |   2 +-
 testcases/kernel/syscalls/fanotify/.gitignore |   1 +
 testcases/kernel/syscalls/fanotify/fanotify.h |  26 ++++
 .../kernel/syscalls/fanotify/fanotify20.c     | 128 ++++++++++++++++++
 4 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 testcases/kernel/syscalls/fanotify/fanotify20.c

diff --git a/configure.ac b/configure.ac
index 5bf3c52ec..b62ec5e15 100644
--- a/configure.ac
+++ b/configure.ac
@@ -159,7 +159,7 @@ AC_CHECK_MEMBERS([struct utsname.domainname],,,[
 AC_CHECK_TYPES([enum kcmp_type],,,[#include <linux/kcmp.h>])
 AC_CHECK_TYPES([struct acct_v3],,,[#include <sys/acct.h>])
 AC_CHECK_TYPES([struct af_alg_iv, struct sockaddr_alg],,,[# include <linux/if_alg.h>])
-AC_CHECK_TYPES([struct fanotify_event_info_fid, struct fanotify_event_info_header],,,[#include <sys/fanotify.h>])
+AC_CHECK_TYPES([struct fanotify_event_info_fid, struct fanotify_event_info_header, struct fanotify_event_info_pidfd],,,[#include <sys/fanotify.h>])
 AC_CHECK_TYPES([struct file_dedupe_range],,,[#include <linux/fs.h>])
 
 AC_CHECK_TYPES([struct file_handle],,,[
diff --git a/testcases/kernel/syscalls/fanotify/.gitignore b/testcases/kernel/syscalls/fanotify/.gitignore
index 9554b16b1..c99e6fff7 100644
--- a/testcases/kernel/syscalls/fanotify/.gitignore
+++ b/testcases/kernel/syscalls/fanotify/.gitignore
@@ -17,4 +17,5 @@
 /fanotify17
 /fanotify18
 /fanotify19
+/fanotify20
 /fanotify_child
diff --git a/testcases/kernel/syscalls/fanotify/fanotify.h b/testcases/kernel/syscalls/fanotify/fanotify.h
index a2be18338..c91162d97 100644
--- a/testcases/kernel/syscalls/fanotify/fanotify.h
+++ b/testcases/kernel/syscalls/fanotify/fanotify.h
@@ -78,6 +78,9 @@ static inline int safe_fanotify_mark(const char *file, const int lineno,
 #define FAN_REPORT_NAME		0x00000800
 #define FAN_REPORT_DFID_NAME     (FAN_REPORT_DIR_FID | FAN_REPORT_NAME)
 #endif
+#ifndef FAN_REPORT_PIDFD
+#define FAN_REPORT_PIDFD	0x00000080
+#endif
 
 /* Non-uapi convenience macros */
 #ifndef FAN_REPORT_DFID_NAME_FID
@@ -125,6 +128,14 @@ static inline int safe_fanotify_mark(const char *file, const int lineno,
 #define FAN_OPEN_EXEC_PERM	0x00040000
 #endif
 
+/* Additional error status codes that can be returned to userspace */
+#ifndef FAN_NOPIDFD
+#define FAN_NOPIDFD		-1
+#endif
+#ifndef FAN_EPIDFD
+#define FAN_EPIDFD		-2
+#endif
+
 /* Flags required for unprivileged user group */
 #define FANOTIFY_REQUIRED_USER_INIT_FLAGS    (FAN_REPORT_FID)
 
@@ -164,6 +175,9 @@ typedef struct {
 #ifndef FAN_EVENT_INFO_TYPE_DFID
 #define FAN_EVENT_INFO_TYPE_DFID	3
 #endif
+#ifndef FAN_EVENT_INFO_TYPE_PIDFD
+#define FAN_EVENT_INFO_TYPE_PIDFD	4
+#endif
 
 #ifndef HAVE_STRUCT_FANOTIFY_EVENT_INFO_HEADER
 struct fanotify_event_info_header {
@@ -181,6 +195,13 @@ struct fanotify_event_info_fid {
 };
 #endif /* HAVE_STRUCT_FANOTIFY_EVENT_INFO_FID */
 
+#ifndef HAVE_STRUCT_FANOTIFY_EVENT_INFO_PIDFD
+struct fanotify_event_info_pidfd {
+	struct fanotify_event_info_header hdr;
+	int32_t pidfd;
+};
+#endif /* HAVE_STRUCT_FANOTIFY_EVENT_INFO_PIDFD */
+
 /* NOTE: only for struct fanotify_event_info_fid */
 #ifdef HAVE_STRUCT_FANOTIFY_EVENT_INFO_FID_FSID___VAL
 # define FSID_VAL_MEMBER(fsid, i) (fsid.__val[i])
@@ -352,6 +373,11 @@ static inline void fanotify_init_flags_err_msg(const char *flags_str,
 		fanotify_init_flags_supported_on_fs(flags, fname)); \
 	} while (0)
 
+#define REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_BY_KERNEL(flags) do { \
+	fanotify_init_flags_err_msg(#flags, __FILE__, __LINE__, tst_brk_, \
+		fanotify_init_flags_supported_by_kernel(flags)); \
+	} while (0)
+
 static inline int fanotify_mark_supported_by_kernel(uint64_t flag)
 {
 	int fd;
diff --git a/testcases/kernel/syscalls/fanotify/fanotify20.c b/testcases/kernel/syscalls/fanotify/fanotify20.c
new file mode 100644
index 000000000..9960d85eb
--- /dev/null
+++ b/testcases/kernel/syscalls/fanotify/fanotify20.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021 Google. All Rights Reserved.
+ *
+ * Started by Matthew Bobrowski <repnop@google.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * This source file contains a test case which ensures that the fanotify API
+ * returns an expected error code when provided an invalid initialization flag
+ * alongside FAN_REPORT_PIDFD. Additionally, it checks that the operability with
+ * existing FAN_REPORT_* flags is maintained and functioning as intended.
+ */
+
+#define _GNU_SOURCE
+#include "tst_test.h"
+#include <errno.h>
+
+#ifdef HAVE_SYS_FANOTIFY_H
+#include "fanotify.h"
+
+#define MOUNT_PATH	"fs_mnt"
+
+static int fanotify_fd;
+
+static struct test_case_t {
+	char *name;
+	unsigned int init_flags;
+	int want_err;
+	int want_errno;
+} test_cases[] = {
+	{
+		"fail on FAN_REPORT_PIDFD | FAN_REPORT_TID",
+		FAN_REPORT_PIDFD | FAN_REPORT_TID,
+		1,
+		EINVAL,
+	},
+	{
+		"pass on FAN_REPORT_PIDFD | FAN_REPORT_FID | FAN_REPORT_DFID_NAME",
+		FAN_REPORT_PIDFD | FAN_REPORT_FID | FAN_REPORT_DFID_NAME ,
+		0,
+		0,
+	},
+};
+
+static void do_setup(void)
+{
+	/*
+	 * An explicit check for FAN_REPORT_PIDFD is performed early on in the
+	 * test initialization as it's a prerequisite for all test cases.
+	 */
+	REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_BY_KERNEL(FAN_REPORT_PIDFD);
+}
+
+static void do_test(unsigned int num)
+{
+	struct test_case_t *tc = &test_cases[num];
+
+	tst_res(TINFO, "Test #%d: %s", num, tc->name);
+
+	fanotify_fd = fanotify_init(tc->init_flags, O_RDONLY);
+	if (fanotify_fd < 0) {
+		if (!tc->want_err) {
+			tst_res(TFAIL,
+				"fanotify_fd=%d, fanotify_init(%x, O_RDONLY) "
+				"failed with error -%d but wanted success",
+				fanotify_fd, tc->init_flags, errno);
+			return;
+		}
+
+		if (errno != tc->want_errno) {
+			tst_res(TFAIL,
+				"fanotify_fd=%d, fanotify_init(%x, O_RDONLY) "
+				"failed with an unexpected error code -%d but "
+				"wanted -%d",
+				fanotify_fd, tc->init_flags,
+				errno, tc->want_errno);
+			return;
+		}
+
+		tst_res(TPASS,
+			"fanotify_fd=%d, fanotify_init(%x, O_RDONLY) "
+			"failed with error -%d as expected",
+			fanotify_fd, tc->init_flags, errno);
+		return;
+	}
+
+	/*
+	 * Catch test cases that had expected to receive an error upon calling
+	 * fanotify_init() but had unexpectedly resulted in a success.
+	 */
+	if (tc->want_err) {
+		tst_res(TFAIL,
+			"fanotify_fd=%d, fanotify_init(%x, O_RDONLY) "
+			"unexpectedly returned successfully, wanted error -%d",
+			fanotify_fd, tc->init_flags, tc->want_errno);
+		return;
+	}
+
+	tst_res(TPASS,
+		"fanotify_fd=%d, fanotify_init(%x, O_RDONLY) "
+		"successfully initialized notification group",
+		fanotify_fd, tc->init_flags);
+
+	SAFE_CLOSE(fanotify_fd);
+}
+
+static void do_cleanup(void)
+{
+	if (fanotify_fd >= 0)
+		SAFE_CLOSE(fanotify_fd);
+}
+
+static struct tst_test test = {
+	.setup = do_setup,
+	.test = do_test,
+	.tcnt = ARRAY_SIZE(test_cases),
+	.cleanup = do_cleanup,
+	.all_filesystems = 1,
+	.needs_root = 1,
+	.mntpoint = MOUNT_PATH,
+};
+
+#else
+	TST_TEST_TCONF("system doesn't have required fanotify support");
+#endif /* HAVE_SYS_FANOTIFY_H */
-- 
2.33.1.1089.g2158813163f-goog

/M

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