From 11350529fee2dbbcfda333bbe10d72f023dc2109 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Mon, 20 Apr 2009 15:13:34 +0100
Subject: [PATCH] Various fixes to the daemon:  - make sure SIGPIPE doesn't
 kill us  - warn not to use macros in FileIn functions  - add shell_quote
 function

---
 daemon/daemon.h   | 19 +++++++++++++++----
 daemon/guestfsd.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/daemon/daemon.h b/daemon/daemon.h
index bd14b12..3f51056 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -44,6 +44,8 @@ extern int command (char **stdoutput, char **stderror, const char *name, ...);
 extern int commandv (char **stdoutput, char **stderror,
 		     char * const* const argv);
 
+extern int shell_quote (char *out, int len, const char *in);
+
 extern int verbose;
 
 /*-- in proto.c --*/
@@ -90,7 +92,9 @@ extern void send_file_end (int cancel);
 /* only call this if there is a FileOut parameter */
 extern void reply (xdrproc_t xdrp, char *ret);
 
-/* Helper for functions that need a root filesystem mounted. */
+/* Helper for functions that need a root filesystem mounted.
+ * NB. Cannot be used for FileIn functions.
+ */
 #define NEED_ROOT(errcode)						\
   do {									\
     if (!root_mounted) {						\
@@ -100,7 +104,9 @@ extern void reply (xdrproc_t xdrp, char *ret);
   }									\
   while (0)
 
-/* Helper for functions that need an argument ("path") that is absolute. */
+/* Helper for functions that need an argument ("path") that is absolute.
+ * NB. Cannot be used for FileIn functions.
+ */
 #define ABS_PATH(path,errcode)						\
   do {									\
     if ((path)[0] != '/') {						\
@@ -109,7 +115,9 @@ extern void reply (xdrproc_t xdrp, char *ret);
     }									\
   } while (0)
 
-/* Helper for functions that need an argument ("path") that is a device. */
+/* Helper for functions that need an argument ("path") that is a device.
+ * NB. Cannot be used for FileIn functions.
+ */
 #define IS_DEVICE(path,errcode)						\
   do {									\
     struct stat statbuf;						\
@@ -125,6 +133,7 @@ extern void reply (xdrproc_t xdrp, char *ret);
 
 /* Helper for functions which need either an absolute path in the
  * mounted filesystem, OR a /dev/ device which exists.
+ * NB. Cannot be used for FileIn functions.
  */
 #define NEED_ROOT_OR_IS_DEVICE(path,errcode) \
   do {									\
@@ -147,7 +156,9 @@ extern void reply (xdrproc_t xdrp, char *ret);
 #define CHROOT_OUT \
   do { int old_errno = errno; chroot ("."); errno = old_errno; } while (0)
 
-/* Marks functions which are not implemented. */
+/* Marks functions which are not implemented.
+ * NB. Cannot be used for FileIn functions.
+ */
 #define XXX_NOT_IMPL(errcode)						\
   do {									\
     reply_with_error ("%s: function not implemented", __func__);	\
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index a957683..d7ba482 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -32,6 +32,8 @@
 #include <sys/select.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <ctype.h>
+#include <signal.h>
 
 #include "daemon.h"
 
@@ -66,6 +68,7 @@ main (int argc, char *argv[])
   struct addrinfo hints;
   XDR xdr;
   uint32_t len;
+  struct sigaction sa;
 
   for (;;) {
     c = getopt_long (argc, argv, options, long_options, NULL);
@@ -140,6 +143,13 @@ main (int argc, char *argv[])
     port = VMCHANNEL_PORT;
   }
 
+  /* Make sure SIGPIPE doesn't kill us. */
+  memset (&sa, 0, sizeof sa);
+  sa.sa_handler = SIG_IGN;
+  sa.sa_flags = 0;
+  if (sigaction (SIGPIPE, &sa, NULL) == -1)
+    perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
+
   /* Resolve the hostname. */
   memset (&hints, 0, sizeof hints);
   hints.ai_socktype = SOCK_STREAM;
@@ -510,3 +520,40 @@ commandv (char **stdoutput, char **stderror, char * const* const argv)
   } else
     return -1;
 }
+
+/* Quote 'in' for the shell, and write max len-1 bytes to out.  The
+ * result will be NUL-terminated, even if it is truncated.
+ *
+ * Returns number of bytes needed, so if result >= len then the buffer
+ * should have been longer.
+ *
+ * XXX This doesn't quote \n correctly (but is still safe).
+ */
+int
+shell_quote (char *out, int len, const char *in)
+{
+#define SAFE(c) (isalnum((c)) ||					\
+		 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
+  int i, j;
+  int outlen = strlen (in);
+
+  /* Calculate how much output space this really needs. */
+  for (i = 0; in[i]; ++i)
+    if (!SAFE (in[i])) outlen++;
+
+  /* Now copy the string, but only up to len-1 bytes. */
+  for (i = 0, j = 0; in[i]; ++i) {
+    int is_safe = SAFE (in[i]);
+
+    /* Enough space left to write this character? */
+    if (j >= len-1 || (!is_safe && j >= len-2))
+      break;
+
+    if (!is_safe) out[j++] = '\\';
+    out[j++] = in[i];
+  }
+
+  out[j] = '\0';
+
+  return outlen;
+}
-- 
1.8.3.1