1 files changed, 30 insertions, 0 deletions
diff --git a/semestr-5/so/lista4/so21_lista_4/leaky.c b/semestr-5/so/lista4/so21_lista_4/leaky.c
new file mode 100644
index 0000000..9257d5c
--- /dev/null
+++ b/semestr-5/so/lista4/so21_lista_4/leaky.c
@@ -0,0 +1,30 @@
+#include "csapp.h"
+
+int main(int argc, char **argv) {
+  long max_fd = sysconf(_SC_OPEN_MAX);
+
+  /* Initialize PRNG seed. */
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  srandom(tv.tv_usec);
+
+  /* This opens a file with password that is checked later. */
+  int fd_1 = Open("mypasswd", O_RDONLY, 0);
+  int fd_2 = 3 + random() % (max_fd - 3);
+  (void)Dup2(fd_1, fd_2);
+  Close(fd_1);
+  Lseek(fd_2, 0, SEEK_END);
+
+  /* TODO: Something is missing here to fix the issue! */
+  fcntl(fd_2, F_SETFD, FD_CLOEXEC);
+  /* Let's suppose a user typed in correct password and was allowed to execute
+   * a command and they choose to run our program. */
+  int rc = system("./innocent");
+  if (rc < 0)
+    unix_error("System error");
+
+  /* At this point we may finally close the file. */
+  Close(fd_2);
+
+  return rc;
+}