su: work when binary has a UNC path

ShellExecuteEx() requires backslashes as the file separator if
the binary to be executed has a UNC path.  Convert separators
unconditionally.

1 files changed, 11 insertions, 1 deletions

diff --git a/loginutils/suw32.c b/loginutils/suw32.c
index d51a7f58c..93fd145f1 100644
--- a/loginutils/suw32.c
+++ b/loginutils/suw32.c
@@ -28,17 +28,27 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
 {
         char *opt_command = NULL;
         SHELLEXECUTEINFO info;
+        char *bb_path, *s;
 
         getopt32(argv, "c:", &opt_command);
         if (argv[optind])
                 bb_show_usage();
 
+        /* ShellExecuteEx() needs backslash as separator in UNC paths. */
+        bb_path = s = xstrdup(bb_busybox_exec_path);
+        for ( ; *s; ++s) {
+                if (*s == '/')
+                        *s = '\\';
+        }
+
         memset(&info, 0, sizeof(SHELLEXECUTEINFO));
         info.cbSize = sizeof(SHELLEXECUTEINFO);
         /* info.fMask = SEE_MASK_DEFAULT; */
         /* info.hwnd = NULL; */
         info.lpVerb = "runas";
-        info.lpFile = bb_busybox_exec_path;
+        info.lpFile = bb_path;
+        /* ShellExecuteEx() always runs system binaries in C:\Windows\System32.
+         * Pass the directory we want to the shell. */
         info.lpParameters = xasprintf("--busybox ash -d \"%s\"", getcwd(NULL, 0));
         if (opt_command)
                 info.lpParameters =