From 8ef17919509e909746b0ad6465e9c6c952a3fe34 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Sun, 19 Jan 2025 14:59:13 +0100
Subject: [PATCH] hurd: Fix EINVAL error on linking to a slash-trailing path
 [BZ #32569]

When the target path finishes with a slash, __file_name_split_at returns
an empty file name. We can test for this to refuse doing the link.
---
 sysdeps/mach/hurd/bind.c      | 8 ++++++--
 sysdeps/mach/hurd/linkat.c    | 6 +++++-
 sysdeps/mach/hurd/mknodat.c   | 8 ++++++--
 sysdeps/mach/hurd/symlinkat.c | 8 ++++++--
 4 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/sysdeps/mach/hurd/bind.c b/sysdeps/mach/hurd/bind.c
index f4cf5bd14e..bb408afcf6 100644
--- a/sysdeps/mach/hurd/bind.c
+++ b/sysdeps/mach/hurd/bind.c
@@ -47,8 +47,12 @@ __bind  (int fd, __CONST_SOCKADDR_ARG addrarg, socklen_t len)
       if (dir == MACH_PORT_NULL)
 	return -1;
 
-      /* Create a new, unlinked node in the target directory.  */
-      err = __dir_mkfile (dir, O_CREAT, 0666 & ~_hurd_umask, &node);
+      if (! *n)
+	/* Can't bind on the existing directory itself.  */
+	err = ENOTDIR;
+      else
+	/* Create a new, unlinked node in the target directory.  */
+	err = __dir_mkfile (dir, O_CREAT, 0666 & ~_hurd_umask, &node);
 
       if (! err)
 	{
diff --git a/sysdeps/mach/hurd/linkat.c b/sysdeps/mach/hurd/linkat.c
index 75b4244f57..8f8e6c36fb 100644
--- a/sysdeps/mach/hurd/linkat.c
+++ b/sysdeps/mach/hurd/linkat.c
@@ -48,7 +48,11 @@ __linkat_common (int fromfd, const char *from, int tofd, const char *to, int at_
   todir = __file_name_split_at (tofd, to, &toname);
   if (todir != MACH_PORT_NULL)
     {
-      err = __dir_link (todir, linknode, toname, 1);
+      if (! *toname)
+	/* Can't link to the existing directory itself.  */
+	err = ENOTDIR;
+      else
+	err = __dir_link (todir, linknode, toname, 1);
       __mach_port_deallocate (__mach_task_self (), todir);
     }
   __mach_port_deallocate (__mach_task_self (), linknode);
diff --git a/sysdeps/mach/hurd/mknodat.c b/sysdeps/mach/hurd/mknodat.c
index 13f2191766..c1fe3430d0 100644
--- a/sysdeps/mach/hurd/mknodat.c
+++ b/sysdeps/mach/hurd/mknodat.c
@@ -88,8 +88,12 @@ __mknodat (int fd, const char *path, mode_t mode, dev_t dev)
   if (dir == MACH_PORT_NULL)
     return -1;
 
-  /* Create a new, unlinked node in the target directory.  */
-  errnode = err = __dir_mkfile (dir, O_WRITE, (mode & ~S_IFMT) & ~_hurd_umask, &node);
+  if (! *name)
+    /* Can't link to the existing directory itself.  */
+    errnode = err = ENOTDIR;
+  else
+    /* Create a new, unlinked node in the target directory.  */
+    errnode = err = __dir_mkfile (dir, O_WRITE, (mode & ~S_IFMT) & ~_hurd_umask, &node);
 
   if (! err && translator != NULL)
     /* Set the node's translator to make it a device.  */
diff --git a/sysdeps/mach/hurd/symlinkat.c b/sysdeps/mach/hurd/symlinkat.c
index 8f72b2bea2..e7dfb673df 100644
--- a/sysdeps/mach/hurd/symlinkat.c
+++ b/sysdeps/mach/hurd/symlinkat.c
@@ -45,8 +45,12 @@ __symlinkat (const char *from, int fd, const char *to)
   if (dir == MACH_PORT_NULL)
     return -1;
 
-  /* Create a new, unlinked node in the target directory.  */
-  err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
+  if (! *name)
+    /* Can't link to the existing directory itself.  */
+    err = ENOTDIR;
+  else
+    /* Create a new, unlinked node in the target directory.  */
+    err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
 
   if (! err)
     {