feat(driver): support for mknod/mknodat syscall

Signed-off-by: Roberto Scolaro <roberto.scolaro21@gmail.com>
Co-Authored-By: Andrea Terzolo <andreaterzolo3@gmail.com>

driver/bpf/fillers.h

@@ -7106,4 +7106,58 @@ FILLER(sys_finit_module_x, true)
 	return bpf_push_u32_to_ring(data, finit_module_flags_to_scap(flags));
 }
 
+FILLER(sys_mknod_x, true)
+{
+
+	/* Parameter 1: ret (type: PT_ERRNO) */
+	long retval = bpf_syscall_get_retval(data->ctx);
+	int res = bpf_push_s64_to_ring(data, retval);
+	CHECK_RES(res);
+
+	/* Parameter 2: path (type: PT_CHARBUF) */
+	unsigned long path_pointer = bpf_syscall_get_argument(data, 0);
+	res = bpf_val_to_ring(data, path_pointer);
+	CHECK_RES(res);
+
+	/* Parameter 3: mode (type: PT_MODE) */
+	u32 mode = bpf_syscall_get_argument(data, 1);
+	res = bpf_push_u32_to_ring(data, mknod_mode_to_scap(mode));
+	CHECK_RES(res);
+
+	/* Parameter 4: dev (type: PT_UINT32) */
+	u32 dev = bpf_syscall_get_argument(data, 2);
+	return bpf_push_u32_to_ring(data, bpf_encode_dev(dev));
+}
+
+FILLER(sys_mknodat_x, true)
+{
+	unsigned long val;
+	s32 fd;
+
+	/* Parameter 1: ret (type: PT_ERRNO) */
+	long retval = bpf_syscall_get_retval(data->ctx);
+	int res = bpf_push_s64_to_ring(data, retval);
+	CHECK_RES(res);
+
+	/* Parameter 2: fd (type: PT_FD) */
+	fd = (s32)bpf_syscall_get_argument(data, 0);
+	if (fd == AT_FDCWD)
+		fd = PPM_AT_FDCWD;
+	res = bpf_push_s64_to_ring(data, (s64)fd);
+	CHECK_RES(res);
+
+	/* Parameter 3: path (type: PT_CHARBUF) */
+	val = bpf_syscall_get_argument(data, 1);
+	res = bpf_val_to_ring(data, val);
+	CHECK_RES(res);
+
+	/* Parameter 4: mode (type: PT_MODE) */
+	u32 mode = bpf_syscall_get_argument(data, 2);
+	res = bpf_push_u32_to_ring(data, mknod_mode_to_scap(mode));
+	CHECK_RES(res);
+
+	/* Parameter 5: dev (type: PT_UINT32) */
+	u32 dev = bpf_syscall_get_argument(data, 3);
+	return bpf_push_u32_to_ring(data, bpf_encode_dev(dev));
+}
 #endif

driver/event_stats.h

@@ -1,7 +1,7 @@
 #pragma once
 
 /* These numbers must be updated when we add new events in the event table */
-#define SYSCALL_EVENTS_NUM 366
+#define SYSCALL_EVENTS_NUM 370
 #define TRACEPOINT_EVENTS_NUM 6
 #define METAEVENTS_NUM 20
 #define PLUGIN_EVENTS_NUM 1

driver/event_table.c

@@ -463,6 +463,10 @@ const struct ppm_event_info g_event_info[] = {
 	[PPME_SYSCALL_INIT_MODULE_X] = {"init_module", EC_OTHER | EC_SYSCALL, EF_NONE, 4, {{"res", PT_ERRNO, PF_DEC}, {"img", PT_BYTEBUF, PF_NA}, {"length", PT_UINT64, PF_DEC}, {"uargs", PT_CHARBUF, PF_NA}}},
 	[PPME_SYSCALL_FINIT_MODULE_E] = {"finit_module", EC_OTHER | EC_SYSCALL, EF_NONE, 0},
 	[PPME_SYSCALL_FINIT_MODULE_X] = {"finit_module", EC_OTHER | EC_SYSCALL, EF_USES_FD | EF_READS_FROM_FD, 4, {{"res", PT_ERRNO, PF_DEC}, {"fd", PT_FD, PF_DEC}, {"uargs", PT_CHARBUF, PF_NA}, {"flags", PT_FLAGS32, PF_DEC}}},
+	[PPME_SYSCALL_MKNOD_E] = {"mknod", EC_OTHER | EC_SYSCALL, EF_NONE, 0},
+	[PPME_SYSCALL_MKNOD_X] = {"mknod", EC_OTHER | EC_SYSCALL, EF_NONE, 4, {{"res", PT_ERRNO, PF_DEC}, {"path", PT_CHARBUF, PF_NA},{"mode", PT_MODE, PF_OCT, mknod_mode},{"dev", PT_UINT32, PF_DEC}}},
+ 	[PPME_SYSCALL_MKNODAT_E] = {"mknodat", EC_OTHER | EC_SYSCALL, EF_NONE, 0},
+	[PPME_SYSCALL_MKNODAT_X] = {"mknodat", EC_OTHER | EC_SYSCALL, EF_USES_FD, 5, {{"res", PT_ERRNO, PF_DEC}, {"dirfd", PT_FD, PF_DEC},{"path", PT_CHARBUF, PF_NA},{"mode", PT_MODE, PF_OCT, mknod_mode},{"dev", PT_UINT32, PF_DEC}}},
 };
 
 // We don't need this check in kmod (this source file is included during kmod compilation!)

driver/fillers_table.c

@@ -347,5 +347,9 @@ const struct ppm_event_entry g_ppm_events[PPM_EVENT_MAX] = {
 	[PPME_SYSCALL_INIT_MODULE_E] = {FILLER_REF(sys_empty)},
 	[PPME_SYSCALL_INIT_MODULE_X] = {FILLER_REF(sys_init_module_x)},
 	[PPME_SYSCALL_FINIT_MODULE_E] = {FILLER_REF(sys_empty)},
-	[PPME_SYSCALL_FINIT_MODULE_X] = {FILLER_REF(sys_finit_module_x)}
+	[PPME_SYSCALL_FINIT_MODULE_X] = {FILLER_REF(sys_finit_module_x)},
+	[PPME_SYSCALL_MKNOD_E] = {FILLER_REF(sys_empty)},
+	[PPME_SYSCALL_MKNOD_X] = {FILLER_REF(sys_mknod_x)},
+	[PPME_SYSCALL_MKNODAT_E] = {FILLER_REF(sys_empty)},
+	[PPME_SYSCALL_MKNODAT_X] = {FILLER_REF(sys_mknodat_x)}
 };

driver/flags_table.c

@@ -684,4 +684,26 @@ const struct ppm_name_value memfd_create_flags[] = {
 const struct ppm_name_value pidfd_open_flags[] = {
 	{"PIDFD_NONBLOCK", PPM_PIDFD_NONBLOCK},
 	{0,0},
-};
+};
+
+const struct ppm_name_value mknod_mode[] = {
+	{"S_IXOTH", PPM_S_IXOTH},
+	{"S_IWOTH", PPM_S_IWOTH},
+	{"S_IROTH", PPM_S_IROTH},
+	{"S_IXGRP", PPM_S_IXGRP},
+	{"S_IWGRP", PPM_S_IWGRP},
+	{"S_IRGRP", PPM_S_IRGRP},
+	{"S_IXUSR", PPM_S_IXUSR},
+	{"S_IWUSR", PPM_S_IWUSR},
+	{"S_IRUSR", PPM_S_IRUSR},
+	{"S_ISVTX", PPM_S_ISVTX},
+	{"S_ISGID", PPM_S_ISGID},
+	{"S_ISUID", PPM_S_ISUID},
+	{"S_IFREG", PPM_S_IFREG},
+	{"S_IFCHR", PPM_S_IFCHR},
+	{"S_IFBLK", PPM_S_IFBLK},
+	{"S_IFIFO", PPM_S_IFIFO},
+	{"S_IFSOCK", PPM_S_IFSOCK},
+	{0, 0},
+};
+

driver/modern_bpf/definitions/events_dimensions.h

@@ -243,6 +243,8 @@
 #define PIDFD_OPEN_X_SIZE HEADER_LEN + sizeof(int64_t) * 2 + sizeof(uint32_t) + 3 * PARAM_LEN
 #define INIT_MODULE_E_SIZE HEADER_LEN
 #define FINIT_MODULE_E_SIZE HEADER_LEN
+#define MKNOD_E_SIZE HEADER_LEN
+#define MKNODAT_E_SIZE HEADER_LEN
 
 /* Generic tracepoints events. */
 #define SCHED_SWITCH_SIZE HEADER_LEN + sizeof(int64_t) + sizeof(uint64_t) * 2 + sizeof(uint32_t) * 3 + PARAM_LEN * 6

driver/modern_bpf/programs/tail_called/events/syscall_dispatched_events/mknod.bpf.c

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2023 The Falco Authors.
+ *
+ * This file is dual licensed under either the MIT or GPL 2. See MIT.txt
+ * or GPL2.txt for full copies of the license.
+ */
+
+#include <helpers/interfaces/fixed_size_event.h>
+#include <helpers/interfaces/variable_size_event.h>
+
+/*=============================== ENTER EVENT ===========================*/
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(mknod_e,
+	     struct pt_regs *regs,
+	     long id)
+{
+	struct ringbuf_struct ringbuf;
+	if(!ringbuf__reserve_space(&ringbuf, ctx, MKNOD_E_SIZE, PPME_SYSCALL_MKNOD_E))
+	{
+		return 0;
+	}
+
+	ringbuf__store_event_header(&ringbuf);
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	// Here we have no parameters to collect.
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	ringbuf__submit_event(&ringbuf);
+
+	return 0;
+
+
+}
+
+/*=============================== ENTER EVENT ===========================*/
+
+/*=============================== EXIT EVENT ===========================*/
+
+SEC("tp_btf/sys_exit")
+int BPF_PROG(mknod_x,
+	     struct pt_regs *regs,
+	     long ret)
+{
+	struct auxiliary_map *auxmap = auxmap__get();
+	if(!auxmap)
+	{
+		return 0;
+	}
+
+	auxmap__preload_event_header(auxmap, PPME_SYSCALL_MKNOD_X);
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	/* Parameter 1: ret (type: PT_ERRNO) */
+	auxmap__store_s64_param(auxmap, ret);
+
+	/* Parameter 2: path (type: PT_CHARBUF) */
+	unsigned long path_pointer = extract__syscall_argument(regs, 0);
+	auxmap__store_charbuf_param(auxmap, path_pointer, MAX_PATH, USER);
+
+	/* Parameter 3: mode (type: PT_MODE) */
+	u32 mode = (u32)extract__syscall_argument(regs, 1);
+	auxmap__store_u32_param(auxmap,mknod_mode_to_scap(mode));
+
+	/* Parameter 4: dev (type: PT_UINT32) */
+	u32 dev = (u32)extract__syscall_argument(regs, 2);
+	auxmap__store_u32_param(auxmap, encode_dev(dev));
+
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	auxmap__finalize_event_header(auxmap);
+
+	auxmap__submit_event(auxmap, ctx);
+
+	return 0;
+}
+
+/*=============================== EXIT EVENT ===========================*/

driver/modern_bpf/programs/tail_called/events/syscall_dispatched_events/mknodat.bpf.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2023 The Falco Authors.
+ *
+ * This file is dual licensed under either the MIT or GPL 2. See MIT.txt
+ * or GPL2.txt for full copies of the license.
+ */
+
+#include <helpers/interfaces/fixed_size_event.h>
+#include <helpers/interfaces/variable_size_event.h>
+
+/*=============================== ENTER EVENT ===========================*/
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(mknodat_e,
+	     struct pt_regs *regs,
+	     long id)
+{
+	struct ringbuf_struct ringbuf;
+	if(!ringbuf__reserve_space(&ringbuf, ctx, MKNODAT_E_SIZE, PPME_SYSCALL_MKNODAT_E))
+	{
+		return 0;
+	}
+
+	ringbuf__store_event_header(&ringbuf);
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	// Here we have no parameters to collect.
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	ringbuf__submit_event(&ringbuf);
+
+	return 0;
+
+
+}
+
+/*=============================== ENTER EVENT ===========================*/
+
+/*=============================== EXIT EVENT ===========================*/
+
+SEC("tp_btf/sys_exit")
+int BPF_PROG(mknodat_x,
+	     struct pt_regs *regs,
+	     long ret)
+{
+	struct auxiliary_map *auxmap = auxmap__get();
+	if(!auxmap)
+	{
+		return 0;
+	}
+
+	auxmap__preload_event_header(auxmap, PPME_SYSCALL_MKNODAT_X);
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	/* Parameter 1: ret (type: PT_ERRNO) */
+	auxmap__store_s64_param(auxmap, ret);
+
+	/* Parameter 2: dirfd (type: PT_FD) */
+	s32 dirfd = (s32)extract__syscall_argument(regs, 0);
+	if(dirfd == AT_FDCWD)
+	{
+		dirfd = PPM_AT_FDCWD;
+	}
+	auxmap__store_s64_param(auxmap, (s64)dirfd);
+
+	/* Parameter 2: path (type: PT_CHARBUF) */
+	unsigned long path_pointer = extract__syscall_argument(regs, 1);
+	auxmap__store_charbuf_param(auxmap, path_pointer, MAX_PATH, USER);
+
+	/* Parameter 3: mode (type: PT_MODE) */
+	u32 mode = (u32)extract__syscall_argument(regs, 2);
+	auxmap__store_u32_param(auxmap, mknod_mode_to_scap(mode));
+
+	/* Parameter 4: dev (type: PT_UINT32) */
+	u32 dev = (u32)extract__syscall_argument(regs, 3);
+	auxmap__store_u32_param(auxmap, encode_dev(dev));
+
+
+	/*=============================== COLLECT PARAMETERS  ===========================*/
+
+	auxmap__finalize_event_header(auxmap);
+
+	auxmap__submit_event(auxmap, ctx);
+
+	return 0;
+}
+
+/*=============================== EXIT EVENT ===========================*/

driver/ppm_events_public.h

@@ -117,6 +117,15 @@ or GPL2.txt for full copies of the license.
 #define PPM_S_ISGID (1 << 10)
 #define PPM_S_ISUID (1 << 11)
 
+/*
+ * mknod() modes
+ */
+#define PPM_S_IFREG  0100000
+#define PPM_S_IFCHR  0020000
+#define PPM_S_IFBLK  0060000
+#define PPM_S_IFIFO  0010000
+#define PPM_S_IFSOCK 0140000
+
 /*
  * flock() flags
  */
@@ -1394,7 +1403,11 @@ typedef enum {
 	PPME_SYSCALL_INIT_MODULE_X = 411,
 	PPME_SYSCALL_FINIT_MODULE_E = 412,
 	PPME_SYSCALL_FINIT_MODULE_X = 413,
-	PPM_EVENT_MAX = 414
+	PPME_SYSCALL_MKNOD_E = 414,
+	PPME_SYSCALL_MKNOD_X = 415,
+	PPME_SYSCALL_MKNODAT_E = 416,
+	PPME_SYSCALL_MKNODAT_X = 417,
+	PPM_EVENT_MAX = 418
 } ppm_event_code;
 /*@}*/
 
@@ -2090,6 +2103,7 @@ extern const struct ppm_name_value pf_flags[];
 extern const struct ppm_name_value unlinkat_flags[];
 extern const struct ppm_name_value linkat_flags[];
 extern const struct ppm_name_value chmod_mode[];
+extern const struct ppm_name_value mknod_mode[];
 extern const struct ppm_name_value renameat2_flags[];
 extern const struct ppm_name_value openat2_flags[];
 extern const struct ppm_name_value execve_flags[];