From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 18 Jun 2020 04:48:45 +0000 (+0900)
Subject: udev: udev_event_apply_format() always make buf NUL terminated
X-Git-Tag: v246-rc1~137^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5eb6ef8b452ef15788cc0c7d176be38a2cef8ca2;p=thirdparty%2Fsystemd.git

udev: udev_event_apply_format() always make buf NUL terminated

The return value of udev_event_apply_format() is always ignored.
So, the destination buffer must be always NUL terminated.
---

diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
index 309cfebc8d2..b468ce9c034 100644
--- a/src/udev/udev-event.c
+++ b/src/udev/udev-event.c
@@ -437,9 +437,9 @@ null_terminate:
         return 0;
 }
 
-ssize_t udev_event_apply_format(UdevEvent *event,
-                                const char *src, char *dest, size_t size,
-                                bool replace_whitespace) {
+size_t udev_event_apply_format(UdevEvent *event,
+                               const char *src, char *dest, size_t size,
+                               bool replace_whitespace) {
         const char *s = src;
         int r;
 
@@ -455,9 +455,10 @@ ssize_t udev_event_apply_format(UdevEvent *event,
                 ssize_t subst_len;
 
                 r = get_subst_type(&s, false, &type, attr);
-                if (r < 0)
-                        return log_device_warning_errno(event->dev, r, "Invalid format string, ignoring: %s", src);
-                if (r == 0) {
+                if (r < 0) {
+                        log_device_warning_errno(event->dev, r, "Invalid format string, ignoring: %s", src);
+                        break;
+                } else if (r == 0) {
                         if (size < 2) /* need space for this char and the terminating NUL */
                                 break;
                         *dest++ = *s++;
@@ -466,10 +467,12 @@ ssize_t udev_event_apply_format(UdevEvent *event,
                 }
 
                 subst_len = udev_event_subst_format(event, type, attr, dest, size);
-                if (subst_len < 0)
-                        return log_device_warning_errno(event->dev, subst_len,
-                                                        "Failed to substitute variable '$%s' or apply format '%%%c', ignoring: %m",
-                                                        format_type_to_string(type), format_type_to_char(type));
+                if (subst_len < 0) {
+                        log_device_warning_errno(event->dev, subst_len,
+                                                 "Failed to substitute variable '$%s' or apply format '%%%c', ignoring: %m",
+                                                 format_type_to_string(type), format_type_to_char(type));
+                        break;
+                }
 
                 /* FORMAT_SUBST_RESULT handles spaces itself */
                 if (replace_whitespace && type != FORMAT_SUBST_RESULT)
diff --git a/src/udev/udev-event.h b/src/udev/udev-event.h
index a78cea440da..a0193ffef35 100644
--- a/src/udev/udev-event.h
+++ b/src/udev/udev-event.h
@@ -48,9 +48,9 @@ UdevEvent *udev_event_new(sd_device *dev, usec_t exec_delay_usec, sd_netlink *rt
 UdevEvent *udev_event_free(UdevEvent *event);
 DEFINE_TRIVIAL_CLEANUP_FUNC(UdevEvent*, udev_event_free);
 
-ssize_t udev_event_apply_format(UdevEvent *event,
-                                const char *src, char *dest, size_t size,
-                                bool replace_whitespace);
+size_t udev_event_apply_format(UdevEvent *event,
+                               const char *src, char *dest, size_t size,
+                               bool replace_whitespace);
 int udev_check_format(const char *value, size_t *offset, const char **hint);
 int udev_event_spawn(UdevEvent *event,
                      usec_t timeout_usec,
diff --git a/src/udev/udevadm-test.c b/src/udev/udevadm-test.c
index 8b348098990..3f8bdc28120 100644
--- a/src/udev/udevadm-test.c
+++ b/src/udev/udevadm-test.c
@@ -151,7 +151,7 @@ int test_main(int argc, char *argv[], void *userdata) {
         ORDERED_HASHMAP_FOREACH_KEY(val, cmd, event->run_list, i) {
                 char program[UTIL_PATH_SIZE];
 
-                udev_event_apply_format(event, cmd, program, sizeof(program), false);
+                (void) udev_event_apply_format(event, cmd, program, sizeof(program), false);
                 printf("run: '%s'\n", program);
         }