conntrack: fix compiler warnings

.... those do not indicate bugs, but they are distracting.

'exp_filter_add' at filter.c:513:2:
__builtin_strncpy specified bound 16 equals destination size [-Wstringop-truncation]

This warning is because the size argument passed to strncpy() is
identical to buffer size, i.e. if hit the resulting string is not
0-terminated.

read_config_yy.y:1625: warning: '__builtin_snprintf' output may be truncated before the last format character [-Wformat-truncation=]
 1625 |         snprintf(policy->name, CTD_HELPER_NAME_LEN, "%s", $2);
read_config_yy.y:1399: warning: '__builtin_snprintf' output may be ...
 1399 |         snprintf(conf.stats.logfile, FILENAME_MAXLEN, "%s", $2);
read_config_yy.y:707: warning: '__builtin_snprintf' output may be ...
  707 |         snprintf(conf.local.path, UNIX_PATH_MAX, "%s", $2);
read_config_yy.y:179: warning: '__builtin_snprintf' output may be ...
  179 |         snprintf(conf.lockfile, FILENAME_MAXLEN, "%s", $2);
read_config_yy.y:124: warning: '__builtin_snprintf' output may be ...
  124 |         snprintf(conf.logfile, FILENAME_MAXLEN, "%s", $2);

... its because the _MAXLEN constants are one less than the output
buffer size, i.e. could use either .._MAXLEN + 1 or sizeof, this uses
sizeof().

Signed-off-by: Florian Westphal <fw@strlen.de>

2 files changed, 6 insertions, 6 deletions

diff --git a/src/filter.c b/src/filter.c
index 6577102..ee316e7 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -476,7 +476,7 @@ struct exp_filter *exp_filter_create(void)
 
 struct exp_filter_item {
 	struct list_head	head;
-	char			helper_name[NFCT_HELPER_NAME_MAX];
+	char			helper_name[NFCT_HELPER_NAME_MAX + 1];
 };
 
 /* this is ugly, but it simplifies read_config_yy.y */
diff --git a/src/read_config_yy.y b/src/read_config_yy.y
index 95845a1..070b349 100644
--- a/src/read_config_yy.y
+++ b/src/read_config_yy.y
@@ -121,7 +121,7 @@ logfile_path : T_LOG T_PATH_VAL
 		     FILENAME_MAXLEN);
 		exit(EXIT_FAILURE);
 	}
-	snprintf(conf.logfile, FILENAME_MAXLEN, "%s", $2);
+	snprintf(conf.logfile, sizeof(conf.logfile), "%s", $2);
 	free($2);
 };
 
@@ -176,7 +176,7 @@ lock : T_LOCK T_PATH_VAL
 		     FILENAME_MAXLEN);
 		exit(EXIT_FAILURE);
 	}
-	snprintf(conf.lockfile, FILENAME_MAXLEN, "%s", $2);
+	snprintf(conf.lockfile, sizeof(conf.lockfile), "%s", $2);
 	free($2);
 };
 
@@ -704,7 +704,7 @@ unix_option : T_PATH T_PATH_VAL
 		     UNIX_PATH_MAX);
 		exit(EXIT_FAILURE);
 	}
-	snprintf(conf.local.path, UNIX_PATH_MAX, "%s", $2);
+	snprintf(conf.local.path, sizeof(conf.local.path), "%s", $2);
 	free($2);
 };
 
@@ -1396,7 +1396,7 @@ stat_logfile_path : T_LOG T_PATH_VAL
 		     FILENAME_MAXLEN);
 		exit(EXIT_FAILURE);
 	}
-	snprintf(conf.stats.logfile, FILENAME_MAXLEN, "%s", $2);
+	snprintf(conf.stats.logfile, sizeof(conf.stats.logfile), "%s", $2);
 	free($2);
 };
 
@@ -1622,7 +1622,7 @@ helper_type: T_HELPER_POLICY T_STRING '{' helper_policy_list '}'
 	}
 
 	policy = (struct ctd_helper_policy *) &e->data;
-	snprintf(policy->name, CTD_HELPER_NAME_LEN, "%s", $2);
+	snprintf(policy->name, sizeof(policy->name), "%s", $2);
 	free($2);
 	/* Now object is complete. */
 	e->type = SYMBOL_HELPER_POLICY_EXPECT_ROOT;