seitan: Initial import

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/build.c b/build.c
new file mode 100644
index 0000000..9695b5e
--- /dev/null
+++ b/build.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+/* SEITAN - Syscall Expressive Interpreter, Transformer and Notifier
+ *
+ * build.c - Build BPF program and transformation table blobs
+ *
+ * Copyright (c) 2022 Red Hat GmbH
+ * Author: Stefano Brivio <sbrivio@redhat.com>
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <linux/audit.h>
+#include <linux/filter.h>
+#include <linux/seccomp.h>
+
+struct syscall_numbers {
+	char name[1024];
+	long number;
+};
+
+enum transform {
+	NONE,
+	FD1_UNIX,
+	FDRET_SRC,
+	DEV_CHECK,
+};
+
+#include "filter.h"
+#include "numbers.h"
+
+struct table {
+	enum transform type;
+	long number;
+
+	char arg[6][1024];
+};
+
+static struct table t[16];
+
+int main(void)
+{
+	struct table *tp = t;
+	char buf[BUFSIZ];
+	FILE *fp;
+	int fd;
+
+	fd = open(BUILD_BPF_OUT, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC,
+		  S_IRUSR | S_IWUSR);
+	write(fd, BUILD_PROFILE, sizeof(BUILD_PROFILE));
+	close(fd);
+
+	fp = fopen(BUILD_IN, "r");
+	while (fgets(buf, BUFSIZ, fp)) {
+		char name[1024];
+		char type[1024];
+		unsigned i;
+
+		if (*buf == '\n' || *buf == '#')
+			continue;
+		if (sscanf(buf, "%s %s " /* syscall, type */
+				"%s %s %s %s %s %s", name, type,
+				tp->arg[0], tp->arg[1], tp->arg[2],
+				tp->arg[3], tp->arg[4], tp->arg[5]) < 3)
+			continue;
+
+		for (i = 0; i < sizeof(numbers) / sizeof(numbers[0]); i++) {
+			if (!strcmp(name, numbers[i].name))
+				break;
+		}
+
+		if (i == sizeof(numbers))
+			continue;
+
+		if (!strcmp(type, "fd1_unix"))
+			tp->type = 1;
+		else if (!strcmp(type, "fdret_src"))
+			tp->type = 2;
+		else if (!strcmp(type, "dev_check"))
+			tp->type = 3;
+		else
+			continue;
+
+		tp->number = numbers[i].number;
+
+		tp++;
+	}
+	fclose(fp);
+
+	fd = open(BUILD_TRANSFORM_OUT,
+		  O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, S_IRUSR | S_IWUSR);
+
+	write(fd, t, sizeof(t));
+	close(fd);
+
+	return 0;
+}