Properly check for short writes when sending the response in nscd

5 files changed, 99 insertions, 62 deletions

diff --git a/ChangeLog b/ChangeLog
index 2284d7f..2791724 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2013-04-15  Andreas Schwab  <schwab@suse.de>
+
+	* nscd/grpcache.c (cache_addgr): Properly check for short write.
+	* nscd/initgrcache.c (addinitgroupsX): Likewise.
+	* nscd/pwdcache.c (cache_addpw): Likewise.
+	* nscd/servicescache.c (cache_addserv): Likewise.  Don't write
+	more than recsize.
+
 2013-04-15  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
 	* benchtests/Makefile (bench): Write all output to
diff --git a/nscd/grpcache.c b/nscd/grpcache.c
index d25d8e9..5658792 100644
--- a/nscd/grpcache.c
+++ b/nscd/grpcache.c
@@ -75,8 +75,8 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	     const void *key, struct group *grp, uid_t owner,
 	     struct hashentry *const he, struct datahead *dh, int errval)
 {
+  bool all_written = true;
   ssize_t total;
-  ssize_t written;
   time_t t = time (NULL);
 
   /* We allocate all data in one memory block: the iov vector,
@@ -105,7 +105,7 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	  /* Reload with the same time-to-live value.  */
 	  timeout = dh->timeout = t + db->postimeout;
 
-	  written = total = 0;
+	  total = 0;
 	}
       else
 	{
@@ -113,11 +113,10 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	     case.  */
 	  total = sizeof (notfound);
 
-	  if (fd != -1)
-	    written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
-						MSG_NOSIGNAL));
-	  else
-	    written = total;
+	  if (fd != -1
+	      && TEMP_FAILURE_RETRY (send (fd, &notfound, total,
+					   MSG_NOSIGNAL)) != total)
+	    all_written = false;
 
 	  /* If we have a transient error or cannot permanently store
 	     the result, so be it.  */
@@ -197,9 +196,9 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	  gr_mem_len_total += gr_mem_len[gr_mem_cnt];
 	}
 
-      written = total = (offsetof (struct dataset, strdata)
-			 + gr_mem_cnt * sizeof (uint32_t)
-			 + gr_name_len + gr_passwd_len + gr_mem_len_total);
+      total = (offsetof (struct dataset, strdata)
+	       + gr_mem_cnt * sizeof (uint32_t)
+	       + gr_name_len + gr_passwd_len + gr_mem_len_total);
 
       /* If we refill the cache, first assume the reconrd did not
 	 change.  Allocate memory on the cache since it is likely
@@ -328,20 +327,27 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 		      <= (sizeof (struct database_pers_head)
 			  + db->head->module * sizeof (ref_t)
 			  + db->head->data_size));
-	      written = sendfileall (fd, db->wr_fd,
-				     (char *) &dataset->resp
-				     - (char *) db->head, dataset->head.recsize);
+	      ssize_t written = sendfileall (fd, db->wr_fd,
+					     (char *) &dataset->resp
+					     - (char *) db->head,
+					     dataset->head.recsize);
+	      if (written != dataset->head.recsize)
+		{
 # ifndef __ASSUME_SENDFILE
-	      if (written == -1 && errno == ENOSYS)
-		goto use_write;
+		  if (written == -1 && errno == ENOSYS)
+		    goto use_write;
 # endif
+		  all_written = false;
+		}
 	    }
 	  else
 # ifndef __ASSUME_SENDFILE
 	  use_write:
 # endif
 #endif
-	    written = writeall (fd, &dataset->resp, dataset->head.recsize);
+	    if (writeall (fd, &dataset->resp, dataset->head.recsize)
+		!= dataset->head.recsize)
+	      all_written = false;
 	}
 
       /* Add the record to the database.  But only if it has not been
@@ -401,7 +407,7 @@ cache_addgr (struct database_dyn *db, int fd, request_header *req,
 	}
     }
 
-  if (__builtin_expect (written != total, 0) && debug_level > 0)
+  if (__builtin_expect (!all_written, 0) && debug_level > 0)
     {
       char buf[256];
       dbg_log (_("short write in %s: %s"),  __FUNCTION__,
diff --git a/nscd/initgrcache.c b/nscd/initgrcache.c
index 196407c..462780e 100644
--- a/nscd/initgrcache.c
+++ b/nscd/initgrcache.c
@@ -171,15 +171,16 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 	nip = nip->next;
     }
 
+  bool all_written;
   ssize_t total;
-  ssize_t written;
   time_t timeout;
  out:
+  all_written = true;
   timeout = MAX_TIMEOUT_VALUE;
   if (!any_success)
     {
       /* Nothing found.  Create a negative result record.  */
-      written = total = sizeof (notfound);
+      total = sizeof (notfound);
 
       if (he != NULL && all_tryagain)
 	{
@@ -197,9 +198,10 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 	{
 	  /* We have no data.  This means we send the standard reply for this
 	     case.  */
-	  if (fd != -1)
-	    written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
-						MSG_NOSIGNAL));
+	  if (fd != -1
+	      && TEMP_FAILURE_RETRY (send (fd, &notfound, total,
+					   MSG_NOSIGNAL)) != total)
+	    all_written = false;
 
 	  /* If we have a transient error or cannot permanently store
 	     the result, so be it.  */
@@ -251,8 +253,7 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
   else
     {
 
-      written = total = (offsetof (struct dataset, strdata)
-			 + start * sizeof (int32_t));
+      total = offsetof (struct dataset, strdata) + start * sizeof (int32_t);
 
       /* If we refill the cache, first assume the reconrd did not
 	 change.  Allocate memory on the cache since it is likely
@@ -365,20 +366,27 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 		      <= (sizeof (struct database_pers_head)
 			  + db->head->module * sizeof (ref_t)
 			  + db->head->data_size));
-	      written = sendfileall (fd, db->wr_fd,
-				     (char *) &dataset->resp
-				     - (char *) db->head, dataset->head.recsize);
+	      ssize_t written = sendfileall (fd, db->wr_fd,
+					     (char *) &dataset->resp
+					     - (char *) db->head,
+					     dataset->head.recsize);
+	      if (written != dataset->head.recsize)
+		{
 # ifndef __ASSUME_SENDFILE
-	      if (written == -1 && errno == ENOSYS)
-		goto use_write;
+		  if (written == -1 && errno == ENOSYS)
+		    goto use_write;
 # endif
+		  all_written = false;
+		}
 	    }
 	  else
 # ifndef __ASSUME_SENDFILE
 	  use_write:
 # endif
 #endif
-	    written = writeall (fd, &dataset->resp, dataset->head.recsize);
+	    if (writeall (fd, &dataset->resp, dataset->head.recsize)
+		!= dataset->head.recsize)
+	      all_written = false;
 	}
 
 
@@ -405,7 +413,7 @@ addinitgroupsX (struct database_dyn *db, int fd, request_header *req,
 
   free (groups);
 
-  if (__builtin_expect (written != total, 0) && debug_level > 0)
+  if (__builtin_expect (!all_written, 0) && debug_level > 0)
     {
       char buf[256];
       dbg_log (_("short write in %s: %s"), __FUNCTION__,
diff --git a/nscd/pwdcache.c b/nscd/pwdcache.c
index ef492b5..4f3fb41 100644
--- a/nscd/pwdcache.c
+++ b/nscd/pwdcache.c
@@ -81,8 +81,8 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 	     const void *key, struct passwd *pwd, uid_t owner,
 	     struct hashentry *const he, struct datahead *dh, int errval)
 {
+  bool all_written = true;
   ssize_t total;
-  ssize_t written;
   time_t t = time (NULL);
 
   /* We allocate all data in one memory block: the iov vector,
@@ -111,17 +111,18 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 	  /* Reload with the same time-to-live value.  */
 	  timeout = dh->timeout = t + db->postimeout;
 
-	  written = total = 0;
+	  total = 0;
 	}
       else
 	{
 	  /* We have no data.  This means we send the standard reply for this
 	     case.  */
-	  written = total = sizeof (notfound);
+	  total = sizeof (notfound);
 
-	  if (fd != -1)
-	    written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
-						MSG_NOSIGNAL));
+	  if (fd != -1
+	      && TEMP_FAILURE_RETRY (send (fd, &notfound, total,
+					   MSG_NOSIGNAL)) != total)
+	    all_written = false;
 
 	  /* If we have a transient error or cannot permanently store
 	     the result, so be it.  */
@@ -189,9 +190,9 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
       n = snprintf (buf, buf_len, "%d%c%n%s", pwd->pw_uid, '\0',
 		    &key_offset, (char *) key) + 1;
 
-      written = total = (offsetof (struct dataset, strdata)
-			 + pw_name_len + pw_passwd_len
-			 + pw_gecos_len + pw_dir_len + pw_shell_len);
+      total = (offsetof (struct dataset, strdata)
+	       + pw_name_len + pw_passwd_len
+	       + pw_gecos_len + pw_dir_len + pw_shell_len);
 
       /* If we refill the cache, first assume the reconrd did not
 	 change.  Allocate memory on the cache since it is likely
@@ -304,20 +305,27 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 		      <= (sizeof (struct database_pers_head)
 			  + db->head->module * sizeof (ref_t)
 			  + db->head->data_size));
-	      written = sendfileall (fd, db->wr_fd,
-				     (char *) &dataset->resp
-				     - (char *) db->head, dataset->head.recsize );
+	      ssize_t written = sendfileall (fd, db->wr_fd,
+					     (char *) &dataset->resp
+					     - (char *) db->head,
+					     dataset->head.recsize);
+	      if (written != dataset->head.recsize)
+		{
 # ifndef __ASSUME_SENDFILE
-	      if (written == -1 && errno == ENOSYS)
-		goto use_write;
+		  if (written == -1 && errno == ENOSYS)
+		    goto use_write;
 # endif
+		  all_written = false;
+		}
 	    }
 	  else
 # ifndef __ASSUME_SENDFILE
 	  use_write:
 # endif
 #endif
-	    written = writeall (fd, &dataset->resp, dataset->head.recsize);
+	    if (writeall (fd, &dataset->resp, dataset->head.recsize)
+		!= dataset->head.recsize)
+	      all_written = false;
 	}
 
 
@@ -377,7 +385,7 @@ cache_addpw (struct database_dyn *db, int fd, request_header *req,
 	}
     }
 
-  if (__builtin_expect (written != total, 0) && debug_level > 0)
+  if (__builtin_expect (!all_written, 0) && debug_level > 0)
     {
       char buf[256];
       dbg_log (_("short write in %s: %s"),  __FUNCTION__,
diff --git a/nscd/servicescache.c b/nscd/servicescache.c
index d29cde7..ebb8c45 100644
--- a/nscd/servicescache.c
+++ b/nscd/servicescache.c
@@ -65,8 +65,8 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 	       const void *key, struct servent *serv, uid_t owner,
 	       struct hashentry *const he, struct datahead *dh, int errval)
 {
+  bool all_written = true;
   ssize_t total;
-  ssize_t written;
   time_t t = time (NULL);
 
   /* We allocate all data in one memory block: the iov vector,
@@ -95,17 +95,18 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 	  /* Reload with the same time-to-live value.  */
 	  timeout = dh->timeout = t + db->postimeout;
 
-	  written = total = 0;
+	  total = 0;
 	}
       else
 	{
 	  /* We have no data.  This means we send the standard reply for this
 	     case.  */
-	  written = total = sizeof (notfound);
+	  total = sizeof (notfound);
 
-	  if (fd != -1)
-	    written = TEMP_FAILURE_RETRY (send (fd, &notfound, total,
-						MSG_NOSIGNAL));
+	  if (fd != -1
+	      && TEMP_FAILURE_RETRY (send (fd, &notfound, total,
+					   MSG_NOSIGNAL)) != total)
+	    all_written = false;
 
 	  /* If we have a transient error or cannot permanently store
 	     the result, so be it.  */
@@ -182,7 +183,6 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 		+ s_name_len
 		+ s_proto_len
 		+ s_aliases_cnt * sizeof (uint32_t));
-      written = total;
 
       /* If we refill the cache, first assume the reconrd did not
 	 change.  Allocate memory on the cache since it is likely
@@ -290,25 +290,32 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 	    {
 	      assert (db->wr_fd != -1);
 	      assert ((char *) &dataset->resp > (char *) db->data);
-	      assert ((char *) &dataset->resp - (char *) db->head
+	      assert ((char *) dataset - (char *) db->head
 		      + total
 		      <= (sizeof (struct database_pers_head)
 			  + db->head->module * sizeof (ref_t)
 			  + db->head->data_size));
-	      written = sendfileall (fd, db->wr_fd,
-				     (char *) &dataset->resp
-				     - (char *) db->head, total);
+	      ssize_t written = sendfileall (fd, db->wr_fd,
+					     (char *) &dataset->resp
+					     - (char *) db->head,
+					     dataset->head.recsize);
+	      if (written != dataset->head.recsize)
+		{
 # ifndef __ASSUME_SENDFILE
-	      if (written == -1 && errno == ENOSYS)
-		goto use_write;
+		  if (written == -1 && errno == ENOSYS)
+		    goto use_write;
 # endif
+		  all_written = false;
+		}
 	    }
 	  else
 # ifndef __ASSUME_SENDFILE
 	  use_write:
 # endif
 #endif
-	    written = writeall (fd, &dataset->resp, total);
+	    if (writeall (fd, &dataset->resp, dataset->head.recsize)
+		!= dataset->head.recsize)
+	      all_written = false;
 	}
 
       /* Add the record to the database.  But only if it has not been
@@ -332,7 +339,7 @@ cache_addserv (struct database_dyn *db, int fd, request_header *req,
 	}
     }
 
-  if (__builtin_expect (written != total, 0) && debug_level > 0)
+  if (__builtin_expect (!all_written, 0) && debug_level > 0)
     {
       char buf[256];
       dbg_log (_("short write in %s: %s"),  __FUNCTION__,