[Libguestfs] [PATCH 2/3] touch: Restrict touch to regular files only (RHBZ#582484).

[Richard W.M. Jones]

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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>From 74958b0ad44df6ed703cd3009983d04ade3a8e93 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones at redhat.com>
Date: Fri, 4 Jun 2010 11:55:54 +0100
Subject: [PATCH 2/3] touch: Restrict touch to regular files only (RHBZ#582484).

---
 daemon/file.c    |   20 ++++++++++++++++++++
 src/generator.ml |    5 ++++-
 2 files changed, 24 insertions(+), 1 deletions(-)

diff --git a/daemon/file.c b/daemon/file.c
index 2594207..9824472 100644
--- a/daemon/file.c
+++ b/daemon/file.c
@@ -34,6 +34,26 @@ do_touch (const char *path)
 {
   int fd;
   int r;
+  struct stat buf;
+
+  /* RHBZ#582484: Restrict touch to regular files.  It's also OK
+   * here if the file does not exist, since we will create it.
+   */
+  CHROOT_IN;
+  r = lstat (path, &buf);
+  CHROOT_OUT;
+
+  if (r == -1) {
+    if (errno != ENOENT) {
+      reply_with_perror ("lstat: %s", path);
+      return -1;
+    }
+  } else {
+    if (! S_ISREG (buf.st_mode)) {
+      reply_with_error ("%s: touch can only be used on a regular files", path);
+      return -1;
+    }
+  }
 
   CHROOT_IN;
   fd = open (path, O_WRONLY | O_CREAT | O_NOCTTY, 0666);
diff --git a/src/generator.ml b/src/generator.ml
index ec6123a..c7dbdfc 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -992,7 +992,10 @@ closing the handle.");
    "\
 Touch acts like the L<touch(1)> command.  It can be used to
 update the timestamps on a file, or, if the file does not exist,
-to create a new zero-length file.");
+to create a new zero-length file.
+
+This command only works on regular files, and will fail on other
+file types such as directories, symbolic links, block special etc.");
 
   ("cat", (RString "content", [Pathname "path"]), 4, [ProtocolLimitWarning],
    [InitISOFS, Always, TestOutput (
-- 
1.6.6.1