stabbish

commit 6d7ea95206f370df80d8774856f81579dc5600cb
parent 6d82ae0f70fc61dbd592e4d721757c662358e4ac
Author: Szymon Mikulicz <szymon.mikulicz@posteo.net>
Date:   Fri,  3 Jul 2026 15:12:36 +0200

Sumthin

Diffstat:
M
main.c
 | 
18
++++++++++++++----

1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/main.c b/main.c
@@ -5,6 +5,7 @@
 #include <malloc.h>
 #include <sched.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <unistd.h>
@@ -50,11 +51,20 @@ const size_t MAGICS_size = sizeof(MAGICS) / sizeof(MAGICS[0]);
   }
 
 int main(int argc, char **argv) {
-  int bbox, script, self;
+  int bbox, script, self, envfile;
   size_t self_size;
   unsigned char *self_map;
 
   checkerr(bbox = memfd_create("busybox", 0), != -1);
+  checkerr(envfile = memfd_create("envfile", 0), != -1);
+  dprintf(envfile, "export ENV; echo No payload present, starting shell.");
+
+  char *envstr;
+  checkerr(asprintf(&envstr, "/dev/fd/%i", envfile), != -1);
+  setenv("ENV", envstr, 1);
+
+  checkerr(asprintf(&envstr, "/dev/fd/%i", bbox), != -1);
+  setenv("BUSYBOX", envstr, 1);
 
   checkerr(write(bbox, _inc_busybox, _inc_busybox_size), != -1);
 
@@ -88,11 +98,11 @@ int main(int argc, char **argv) {
   checkerr(write(script, &self_map[payload_i], payload_size), != -1);
   munmap(self_map, self_size);
 
-  char scriptarg[1024];
+  char *scriptarg;
   if (tool)
-    snprintf(scriptarg, 1024, ". <(%s /dev/fd/%i)", tool, script);
+    asprintf(&scriptarg, ". <(%s /dev/fd/%i)", tool, script);
   else
-    snprintf(scriptarg, 1024, ". /dev/fd/%i", script);
+    asprintf(&scriptarg, ". /dev/fd/%i", script);
 
   char **newargv = malloc(sizeof(char *) * (argc + 4));
   newargv[0] = "ash";