Fix access of freed memory in namehints

Sometimes a hook manipulates the config tree, which makes currently
running iterators point to freed memory. As a workaround, make two
copies, one for the iterators and another for the hooks.

BugLink: https://bugs.launchpad.net/bugs/1008600
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/control/namehint.c b/src/control/namehint.c
index 8d5e925..28975a4 100644 (file)
--- a/src/control/namehint.c
+++ b/src/control/namehint.c
@@ -406,7 +406,7 @@ static const next_devices_t next_devices[] = {
 };
 #endif
 
-static int add_card(snd_config_t *config, struct hint_list *list, int card)
+static int add_card(snd_config_t *config, snd_config_t *rw_config, struct hint_list *list, int card)
 {
        int err, ok;
        snd_config_t *conf, *n;
@@ -449,7 +449,7 @@ static int add_card(snd_config_t *config, struct hint_list *list, int card)
                        ok = 0;
                        for (device = 0; err >= 0 && device <= max_device; device++) {
                                list->device = device;
-                               err = try_config(config, list, list->siface, str);
+                               err = try_config(rw_config, list, list->siface, str);
                                if (err < 0)
                                        break;
                                ok++;
@@ -464,7 +464,7 @@ static int add_card(snd_config_t *config, struct hint_list *list, int card)
                if (err < 0) {
                        list->card = card;
                        list->device = -1;
-                       err = try_config(config, list, list->siface, str);
+                       err = try_config(rw_config, list, list->siface, str);
                }
                if (err == -ENOMEM)
                        goto __error;
@@ -493,7 +493,8 @@ static int get_card_name(struct hint_list *list, int card)
        return 0;
 }
 
-static int add_software_devices(snd_config_t *config, struct hint_list *list)
+static int add_software_devices(snd_config_t *config, snd_config_t *rw_config,
+                               struct hint_list *list)
 {
        int err;
        snd_config_t *conf, *n;
@@ -509,7 +510,7 @@ static int add_software_devices(snd_config_t *config, struct hint_list *list)
                        continue;
                list->card = -1;
                list->device = -1;
-               err = try_config(config, list, list->siface, str);
+               err = try_config(rw_config, list, list->siface, str);
                if (err == -ENOMEM)
                        return -ENOMEM;
        }
@@ -547,7 +548,7 @@ int snd_device_name_hint(int card, const char *iface, void ***hints)
        struct hint_list list;
        char ehints[24];
        const char *str;
-       snd_config_t *conf, *local_config = NULL;
+       snd_config_t *conf, *local_config = NULL, *local_config_rw = NULL;
        snd_config_update_t *local_config_update = NULL;
        snd_config_iterator_t i, next;
        int err;
@@ -557,6 +558,7 @@ int snd_device_name_hint(int card, const char *iface, void ***hints)
        err = snd_config_update_r(&local_config, &local_config_update, NULL);
        if (err < 0)
                return err;
+       err = snd_config_copy(&local_config_rw, local_config);
        list.list = NULL;
        list.count = list.allocated = 0;
        list.siface = iface;
@@ -586,9 +588,9 @@ int snd_device_name_hint(int card, const char *iface, void ***hints)
        if (card >= 0) {
                err = get_card_name(&list, card);
                if (err >= 0)
-                       err = add_card(local_config, &list, card);
+                       err = add_card(local_config, local_config_rw, &list, card);
        } else {
-               add_software_devices(local_config, &list);
+               add_software_devices(local_config, local_config_rw, &list);
                err = snd_card_next(&card);
                if (err < 0)
                        goto __error;
@@ -596,7 +598,7 @@ int snd_device_name_hint(int card, const char *iface, void ***hints)
                        err = get_card_name(&list, card);
                        if (err < 0)
                                goto __error;
-                       err = add_card(local_config, &list, card);
+                       err = add_card(local_config, local_config_rw, &list, card);
                        if (err < 0)
                                goto __error;
                        err = snd_card_next(&card);
@@ -630,6 +632,8 @@ int snd_device_name_hint(int card, const char *iface, void ***hints)
                if (list.cardname)
                        free(list.cardname);
        }
+       if (local_config_rw)
+               snd_config_delete(local_config_rw);
        if (local_config)
                snd_config_delete(local_config);
        if (local_config_update)