-Wstringop-truncation warning was introduced in GCC-8 as truncation
checker for strncpy and strncat.
Systems using gcc version >= 8 would receive the following warnings:
read_config_yy.c: In function ‘yyparse’:
read_config_yy.y:1594:2: warning: ‘strncpy’ specified bound 16 equals
destination size [-Wstringop-truncation]
1594 | strncpy(policy->name, $2, CTD_HELPER_NAME_LEN);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
read_config_yy.y:1384:2: warning: ‘strncpy’ specified bound 256 equals
destination size [-Wstringop-truncation]
1384 | strncpy(conf.stats.logfile, $2, FILENAME_MAXLEN);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
read_config_yy.y:692:2: warning: ‘strncpy’ specified bound 108 equals
destination size [-Wstringop-truncation]
692 | strncpy(conf.local.path, $2, UNIX_PATH_MAX);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
read_config_yy.y:169:2: warning: ‘strncpy’ specified bound 256 equals
destination size [-Wstringop-truncation]
169 | strncpy(conf.lockfile, $2, FILENAME_MAXLEN);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
read_config_yy.y:119:2: warning: ‘strncpy’ specified bound 256 equals
destination size [-Wstringop-truncation]
119 | strncpy(conf.logfile, $2, FILENAME_MAXLEN);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
main.c: In function ‘main’:
main.c:168:5: warning: ‘strncpy’ specified bound 4096 equals destination size
[-Wstringop-truncation]
168 | strncpy(config_file, argv[i], PATH_MAX);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix the issue by checking for string length first. Also using
snprintf instead.
In addition, correct an off-by-one when warning about maximum config
file path length.
Signed-off-by: Jose M. Guisado Gomez <gui...@riseup.net>
---
src/main.c | 4 ++--
src/read_config_yy.y | 35 +++++++++++++++++++++++++++--------
2 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/src/main.c b/src/main.c
index 7062e12..d4fbbfa 100644
--- a/src/main.c
+++ b/src/main.c
@@ -165,13 +165,13 @@ int main(int argc, char *argv[])
break;
case 'C':
if (++i < argc) {
- strncpy(config_file, argv[i], PATH_MAX);
if (strlen(argv[i]) >= PATH_MAX){
config_file[PATH_MAX-1]='\0';
dlog(LOG_WARNING, "Path to config file"
" to long. Cutting it down to %d"
- " characters", PATH_MAX);
+ " characters", PATH_MAX - 1);
}
+ snprintf(config_file, PATH_MAX, "%.*s",
PATH_MAX - 1, argv[i]);
break;
}
show_usage(argv[0]);
diff --git a/src/read_config_yy.y b/src/read_config_yy.y
index 4311cd6..696a86d 100644
--- a/src/read_config_yy.y
+++ b/src/read_config_yy.y
@@ -116,7 +116,12 @@ logfile_bool : T_LOG T_OFF
logfile_path : T_LOG T_PATH_VAL
{
- strncpy(conf.logfile, $2, FILENAME_MAXLEN);
+ if (strlen($2) >= FILENAME_MAXLEN) {
+ dlog(LOG_ERR, "Filename is longer than %u characters",
+ FILENAME_MAXLEN - 1);
+ exit(EXIT_FAILURE);
+ }
+ snprintf(conf.logfile, FILENAME_MAXLEN, "%.*s", FILENAME_MAXLEN - 1,
$2);
free($2);
};
@@ -166,7 +171,12 @@ syslog_facility : T_SYSLOG T_STRING
lock : T_LOCK T_PATH_VAL
{
- strncpy(conf.lockfile, $2, FILENAME_MAXLEN);
+ if (strlen($2) >= FILENAME_MAXLEN) {
+ dlog(LOG_ERR, "Filename is longer than %u characters",
+ FILENAME_MAXLEN - 1);
+ exit(EXIT_FAILURE);
+ }
+ snprintf(conf.lockfile, FILENAME_MAXLEN, "%.*s", FILENAME_MAXLEN - 1,
$2);
free($2);
};
@@ -689,13 +699,13 @@ unix_options:
unix_option : T_PATH T_PATH_VAL
{
- strncpy(conf.local.path, $2, UNIX_PATH_MAX);
- free($2);
- if (conf.local.path[UNIX_PATH_MAX - 1]) {
+ if (strlen($2) >= UNIX_PATH_MAX) {
dlog(LOG_ERR, "UNIX Path is longer than %u characters",
UNIX_PATH_MAX - 1);
exit(EXIT_FAILURE);
}
+ snprintf(conf.local.path, UNIX_PATH_MAX, "%.*s", UNIX_PATH_MAX - 1, $2);
+ free($2);
};
unix_option : T_BACKLOG T_NUMBER
@@ -1381,7 +1391,12 @@ stat_logfile_bool : T_LOG T_OFF
stat_logfile_path : T_LOG T_PATH_VAL
{
- strncpy(conf.stats.logfile, $2, FILENAME_MAXLEN);
+ if (strlen($2) >= FILENAME_MAXLEN) {
+ dlog(LOG_ERR, "Log file path is longer than %u characters",
+ FILENAME_MAXLEN - 1);
+ exit(EXIT_FAILURE);
+ }
+ snprintf(conf.stats.logfile, FILENAME_MAXLEN, "%.*s", FILENAME_MAXLEN -
1, $2);
free($2);
};
@@ -1589,11 +1604,15 @@ helper_type: T_HELPER_POLICY T_STRING '{'
helper_policy_list '}'
exit(EXIT_FAILURE);
break;
}
+ if (strlen($2) >= CTD_HELPER_NAME_LEN) {
+ dlog(LOG_ERR, "CTD helper name is longer than %u characters",
+ CTD_HELPER_NAME_LEN - 1);
+ exit(EXIT_FAILURE);
+ }
policy = (struct ctd_helper_policy *) &e->data;
- strncpy(policy->name, $2, CTD_HELPER_NAME_LEN);
+ snprintf(policy->name, CTD_HELPER_NAME_LEN, "%.*s", CTD_HELPER_NAME_LEN
- 1, $2);
free($2);
- policy->name[CTD_HELPER_NAME_LEN-1] = '\0';
/* Now object is complete. */
e->type = SYMBOL_HELPER_POLICY_EXPECT_ROOT;
stack_item_push(&symbol_stack, e);
--
2.23.0.rc1
