Start moving pwnables to new token encryption

packages/ctfbase/ctfbase.mk

@@ -5,7 +5,6 @@ ctfbase-install: ctfbase-build
 
 	$(call COPYTREE, packages/ctfbase/service, $(CTFBASE_PKGDIR)/service)
 
-	cp packages/ctfbase/src/tokencli $(CTFBASE_PKGDIR)/bin/
 	cp packages/ctfbase/src/arc4 $(CTFBASE_PKGDIR)/bin/
 
 ctfbase-clean:

packages/ctfbase/src/Makefile

@@ -1,9 +1,7 @@
-build: tokencli arc4
+build: arc4
 
 arc4: arc4.c
-	$(CC) $(CFLAGS) $(LDFLAGS) -DARC4_MAIN -o $@ $<
-
-tokencli: tokencli.o arc4.o
+arc4: CFLAGS += -DARC4_MAIN
 
 clean:
-	rm -f *.o tokencli arc4
+	rm -f *.o arc4

packages/ctfbase/src/arc4.c

@@ -1 +1 @@
-../../../include/arc4.c
+../../../src/arc4.c

packages/ctfbase/src/arc4.h

@@ -1 +1 @@
-../../../include/arc4.h
+../../../src/arc4.h

packages/pwnables/src/Makefile

@@ -5,11 +5,11 @@ all: build
 
 build: $(TARGETS)
 
-gimmie: gimmie.o token.o
-octopus: octopus.o token.o
-ltraceme: ltraceme.o token.o
-straceme: straceme.o token.o
-killme: killme.o token.o
+gimmie: gimmie.o token.o arc4.o
+octopus: octopus.o token.o arc4.o
+ltraceme: ltraceme.o token.o arc4.o
+straceme: straceme.o token.o arc4.o
+killme: killme.o token.o arc4.o
 
 install: $(TARGETS)
 	install -m 0755 $(TARGETS) $(DESTDIR)/bin

packages/pwnables/src/arc4.c

@@ -0,0 +1 @@
+../../../src/arc4.c

packages/pwnables/src/arc4.h

@@ -0,0 +1 @@
+../../../src/arc4.h

packages/pwnables/src/gimmie.c

@@ -1,4 +1,7 @@
+#include <stdio.h>
 #include <unistd.h>
+#include <stdlib.h>
+#include <sysexits.h>
 #include "token.h"
 
 uint8_t const key[] = {0x5f, 0x64, 0x13, 0x29,
@@ -9,19 +12,10 @@ uint8_t const key[] = {0x5f, 0x64, 0x13, 0x29,
 int
 main(int argc, char *argv[])
 {
-  char    token[200];
-  ssize_t tokenlen;
-
-  tokenlen = read_token("gimmie",
-                        key, sizeof(key),
-                        token, sizeof(token) - 1);
-  if (-1 == tokenlen) {
-    write(1, "Something is broken\nI can't read my token.\n", 43);
-    return 69;
+  if (-1 == print_token("gimmie", key, sizeof(key))) {
+    fprintf(stderr, "Something is broken; I can't read my token.\n");
+    return EX_UNAVAILABLE;
   }
 
-  token[tokenlen++] = '\n';
-  write(1, token, tokenlen);
-
   return 0;
 }

packages/pwnables/src/token.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <limits.h>
+#include "token.h"
+#include "arc4.h"
+
+#ifndef CTF_BASE
+#define CTF_BASE "/var/lib/ctf"
+#endif
+
+ssize_t
+write_token(FILE *out,
+            const char *name,
+            const uint8_t *key, size_t keylen)
+{
+  char    *base;
+  char     path[PATH_MAX];
+  int      pathlen;
+  FILE    *f;
+  ssize_t  ret;
+
+  base = getenv("CTF_BASE");
+  if (! base) base = CTF_BASE;
+
+  pathlen = snprintf(path, sizeof(path) - 1,
+                     "%s/tokens/%s", base, name);
+  path[pathlen] = '\0';
+
+  f = fopen(path, "r");
+  if (NULL == f) return -1;
+  ret = arc4_decrypt_stream(out, f, key, keylen);
+  fclose(f);
+
+  return ret;
+}
+
+ssize_t
+print_token(const char *name,
+            const uint8_t *key, size_t keylen)
+{
+  return write_token(stdout, name, key, keylen);
+}

packages/pwnables/src/token.h

@@ -0,0 +1,15 @@
+#ifndef __TOKEN_H__
+#define __TOKEN_H__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+ssize_t write_token(FILE *out,
+                    const char *name,
+                    const uint8_t *key, size_t keylen);
+ssize_t print_token(const char *name,
+                    const uint8_t *key, size_t keylen);
+
+
+#endif

src/arc4.c

@@ -159,11 +159,11 @@ arc4_decrypt_stream(FILE *out, FILE *in,
   char            sig[4];
   int             i;
 
-  fread(&sig, sizeof(sig), 1, stdin);
+  fread(&sig, sizeof(sig), 1, in);
   if (memcmp(sig, "arc4", 4)) {
     return -1;
   }
-  fread(&seed, sizeof(seed), 1, stdin);
+  fread(&seed, sizeof(seed), 1, in);
 
   arc4_nonce(nonce, sizeof(nonce), &seed, sizeof(seed));
   for (i = 0; i < keylen; i += 1) {
@@ -191,11 +191,8 @@ arc4_decrypt_stream(FILE *out, FILE *in,
 int
 main(int argc, char *argv[])
 {
-  struct arc4_ctx ctx;
-  uint8_t         key[ARC4_KEYLEN] = {0};
-  size_t          keylen;
-  uint8_t         nonce[ARC4_KEYLEN];
-  int             i;
+  uint8_t key[ARC4_KEYLEN] = {0};
+  size_t  keylen;
 
   /* Read key and initialize context */
   {
@@ -206,19 +203,20 @@ main(int argc, char *argv[])
       memcpy(key, ekey, keylen);
     } else {
       keylen = read(3, key, sizeof(key));
+      if (-1 == keylen) {
+        fprintf(stderr, "error: must specify key.\n");
+        return 1;
+      }
     }
   }
 
   if (! argv[1]) {
     if (-1 == arc4_decrypt_stream(stdout, stdin, key, keylen)) {
-      perror("decrypting");
+      fprintf(stderr, "error: not an arc4 stream.\n");
       return 1;
     }
   } else if (0 == strcmp(argv[1], "-e")) {
-    if (-1 == arc4_encrypt_stream(stdout, stdin, key, keylen)) {
-      perror("encrypting");
-      return 1;
-    }
+    arc4_encrypt_stream(stdout, stdin, key, keylen);
   } else {
     fprintf(stderr, "Usage: %s [-e] <PLAINTEXT\n", argv[0]);
     fprintf(stderr, "\n");