initial commit

1 files changed, 98 insertions, 0 deletions

diff --git a/suidcmd.c b/suidcmd.c
new file mode 100644
index 0000000..b601c15
--- /dev/null
+++ b/suidcmd.c
@@ -0,0 +1,98 @@
+/*
+ * build with: gcc -std=c99 -D_GNU_SOURCE=1 -Wall -O2 -ffunction-sections -fdata-sections -fomit-frame-pointer ./suidcmd.c -o ./suidcmd
+ * strip -s ./suidcmd
+ */
+
+#ifdef _HAVE_CONFIG
+#include "config.h"
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/wait.h>
+
+
+#ifndef CMD
+#define CMD "/usr/sbin/ether-wake"
+#endif
+
+
+int safe_exec(const char* cmdWithArgs)
+{
+  pid_t child;
+  if ( (child = fork()) == 0 ) {
+    size_t szCur = 0, szMax = 10;
+    char** args = calloc(szMax, sizeof(char**));
+    const char* cmd = NULL;
+
+    const char* prv = cmdWithArgs;
+    const char* cur = NULL;
+    while ( (cur = strchr(prv, ' ')) ) {
+      if (cmd == NULL)
+        cmd = strndup(prv, cur-prv);
+
+      args[szCur++] = strndup(prv, cur-prv);
+      if (szCur >= szMax) {
+        szMax *= 2;
+        args = realloc(args, sizeof(char**)*szMax);
+      }
+
+      cur++;
+      prv = cur;
+    }
+    if (cmd == NULL) {
+      cmd = cmdWithArgs;
+    } else {
+      args[szCur++] = strndup(prv, cur-prv);
+    }
+    args[szCur] = NULL;
+    execv(cmd, args);
+  } else {
+    int retval = 0;
+    waitpid(child, &retval, 0);
+    return retval;
+  }
+  return -1;
+}
+
+int main(int argc, char** argv)
+{
+  uid_t ruid, euid, suid;
+
+  if (getresuid(&ruid, &euid, &suid) != 0) {
+    perror("getresuid()");
+  } else {
+    printf("%s: RUID:%u , EUID:%u , SUID:%u\n", argv[0], ruid, euid, suid);
+  }
+
+  if (setuid(0) != 0) {
+    perror("setuid(0)");
+  } else printf("%s: setuid(0)\n", argv[0]);
+
+  char* cmd = NULL;
+  if (asprintf(&cmd, "%s", CMD) <= 0) {
+    fprintf(stderr, "%s: asprintf(\"%s\") error\n", argv[0], CMD);
+    return 1;
+  }
+
+  char* prev_cmd = NULL;
+  for (int i = 1; i < argc; ++i) {
+    prev_cmd = cmd;
+    if (asprintf(&cmd, "%s %s", prev_cmd, argv[i]) < 0) {
+      fprintf(stderr, "%s: asprintf(\"%s\") error\n", argv[0], argv[i]);
+      return 1;
+    }
+    free(prev_cmd);
+  }
+
+  int retval = -1;
+  switch ( (retval = safe_exec(cmd)) ) {
+    case -1: fprintf(stderr, "%s: could not create child process..\n", argv[0]); return 1;
+    case 127: fprintf(stderr, "%s: could not execute shell (child process)..\n", argv[0]); return 1;
+    default:
+      printf("%s: child process returned with: %d\n", argv[0], retval);
+  }
+  free(cmd);
+  return 0;
+}