Fix: oom error check, realloc oom leak

print_exclusions can return a NULL pointer on OOM, should be checked.
Also, realloc always need to store result in a different variable than
its input in case it fails (and its returned pointer needs to be checked
for NULL).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng/commands/enable_events.c b/src/bin/lttng/commands/enable_events.c
index 0b3443caa0d983a96f0f5276aa67aa5b25aef657..c6a24ada5222cd161e8287c32c6827eddfa6513a 100644 (file)
--- a/src/bin/lttng/commands/enable_events.c
+++ b/src/bin/lttng/commands/enable_events.c
@@ -624,11 +624,25 @@ int check_exclusion_subsets(const char *event_name,
                                goto error;
                        }
                        if (e == '*') {
+                               char *string;
+                               char **new_exclusion_list;
+
                                /* Excluder is a proper subset of event */
+                               string = strndup(next_excluder, excluder_length);
+                               if (!string) {
+                                       PERROR("strndup error");
+                                       goto error;
+                               }
+                               new_exclusion_list = realloc(exclusion_list,
+                                       sizeof(char **) * (exclusion_count + 1));
+                               if (!new_exclusion_list) {
+                                       PERROR("realloc");
+                                       free(string);
+                                       goto error;
+                               }
+                               exclusion_list = new_exclusion_list;
                                exclusion_count++;
-                               exclusion_list = realloc(exclusion_list, sizeof(char **) * exclusion_count);
-                               exclusion_list[exclusion_count - 1] = strndup(next_excluder, excluder_length);
-
+                               exclusion_list[exclusion_count - 1] = string;
                                break;
                        }
                        if (x != e) {
@@ -829,6 +843,12 @@ static int enable_events(char *session_name)
                        case LTTNG_EVENT_TRACEPOINT:
                                if (opt_loglevel && dom.type != LTTNG_DOMAIN_KERNEL) {
                                        char *exclusion_string = print_exclusions(exclusion_count, exclusion_list);
+
+                                       if (!exclusion_string) {
+                                               PERROR("Cannot allocate exclusion_string");
+                                               error = 1;
+                                               goto end;
+                                       }
                                        MSG("All %s tracepoints%s are enabled in channel %s for loglevel %s",
                                                        get_domain_str(dom.type),
                                                        exclusion_string,
@@ -837,6 +857,12 @@ static int enable_events(char *session_name)
                                        free(exclusion_string);
                                } else {
                                        char *exclusion_string = print_exclusions(exclusion_count, exclusion_list);
+
+                                       if (!exclusion_string) {
+                                               PERROR("Cannot allocate exclusion_string");
+                                               error = 1;
+                                               goto end;
+                                       }
                                        MSG("All %s tracepoints%s are enabled in channel %s",
                                                        get_domain_str(dom.type),
                                                        exclusion_string,
@@ -854,6 +880,12 @@ static int enable_events(char *session_name)
                        case LTTNG_EVENT_ALL:
                                if (opt_loglevel && dom.type != LTTNG_DOMAIN_KERNEL) {
                                        char *exclusion_string = print_exclusions(exclusion_count, exclusion_list);
+
+                                       if (!exclusion_string) {
+                                               PERROR("Cannot allocate exclusion_string");
+                                               error = 1;
+                                               goto end;
+                                       }
                                        MSG("All %s events%s are enabled in channel %s for loglevel %s",
                                                        get_domain_str(dom.type),
                                                        exclusion_string,
@@ -862,6 +894,12 @@ static int enable_events(char *session_name)
                                        free(exclusion_string);
                                } else {
                                        char *exclusion_string = print_exclusions(exclusion_count, exclusion_list);
+
+                                       if (!exclusion_string) {
+                                               PERROR("Cannot allocate exclusion_string");
+                                               error = 1;
+                                               goto end;
+                                       }
                                        MSG("All %s events%s are enabled in channel %s",
                                                        get_domain_str(dom.type),
                                                        exclusion_string,
@@ -1128,6 +1166,11 @@ static int enable_events(char *session_name)
                                        &ev, channel_name,
                                        NULL, exclusion_count, exclusion_list);
                        exclusion_string = print_exclusions(exclusion_count, exclusion_list);
+                       if (!exclusion_string) {
+                               PERROR("Cannot allocate exclusion_string");
+                               error = 1;
+                               goto end;
+                       }
                        if (command_ret < 0) {
                                /* Turn ret to positive value to handle the positive error code */
                                switch (-command_ret) {
@@ -1187,7 +1230,11 @@ static int enable_events(char *session_name)
                        command_ret = lttng_enable_event_with_exclusions(handle, &ev, channel_name,
                                        opt_filter, exclusion_count, exclusion_list);
                        exclusion_string = print_exclusions(exclusion_count, exclusion_list);
-
+                       if (!exclusion_string) {
+                               PERROR("Cannot allocate exclusion_string");
+                               error = 1;
+                               goto end;
+                       }
                        if (command_ret < 0) {
                                switch (-command_ret) {
                                case LTTNG_ERR_FILTER_EXIST: