ALSA: hda - Fix possible races of accesses to connection list array

Like the previous fixes for cache hash accesses, a protection over
accesses to the widget connection list array must be provided.
Together with this action, remove snd_hda_get_conn_list() which can be
always race, and replace it with either snd_hda_get_num_conns() or
snd_hda_get_connections() calls.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

4 files changed, 52 insertions, 56 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index c556fe1c25eb..eb09a3348325 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -334,78 +334,67 @@ static hda_nid_t *lookup_conn_list(struct snd_array *array, hda_nid_t nid)
         return NULL;
 }
 
+/* read the connection and add to the cache */
+static int read_and_add_raw_conns(struct hda_codec *codec, hda_nid_t nid)
+{
+        hda_nid_t list[HDA_MAX_CONNECTIONS];
+        int len;
+
+        len = snd_hda_get_raw_connections(codec, nid, list, ARRAY_SIZE(list));
+        if (len < 0)
+                return len;
+        return snd_hda_override_conn_list(codec, nid, len, list);
+}
+
 /**
- * snd_hda_get_conn_list - get connection list
+ * snd_hda_get_connections - copy connection list
  * @codec: the HDA codec
  * @nid: NID to parse
- * @listp: the pointer to store NID list
+ * @conn_list: connection list array; when NULL, checks only the size
+ * @max_conns: max. number of connections to store
  *
  * Parses the connection list of the given widget and stores the list
  * of NIDs.
  *
  * Returns the number of connections, or a negative error code.
  */
-int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
-                          const hda_nid_t **listp)
+int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
+                            hda_nid_t *conn_list, int max_conns)
 {
         struct snd_array *array = &codec->conn_lists;
-        int len, err;
-        hda_nid_t list[HDA_MAX_CONNECTIONS];
+        int len;
         hda_nid_t *p;
         bool added = false;
 
  again:
+        mutex_lock(&codec->hash_mutex);
+        len = -1;
         /* if the connection-list is already cached, read it */
         p = lookup_conn_list(array, nid);
         if (p) {
-                if (listp)
-                        *listp = p + 2;
-                return p[1];
+                len = p[1];
+                if (conn_list && len > max_conns) {
+                        snd_printk(KERN_ERR "hda_codec: "
+                                   "Too many connections %d for NID 0x%x\n",
+                                   len, nid);
+                        mutex_unlock(&codec->hash_mutex);
+                        return -EINVAL;
+                }
+                if (conn_list && len)
+                        memcpy(conn_list, p + 2, len * sizeof(hda_nid_t));
         }
+        mutex_unlock(&codec->hash_mutex);
+        if (len >= 0)
+                return len;
         if (snd_BUG_ON(added))
                 return -EINVAL;
 
-        /* read the connection and add to the cache */
-        len = snd_hda_get_raw_connections(codec, nid, list, HDA_MAX_CONNECTIONS);
+        len = read_and_add_raw_conns(codec, nid);
         if (len < 0)
                 return len;
-        err = snd_hda_override_conn_list(codec, nid, len, list);
-        if (err < 0)
-                return err;
         added = true;
         goto again;
 }
-EXPORT_SYMBOL_HDA(snd_hda_get_conn_list);
-
-/**
- * snd_hda_get_connections - copy connection list
- * @codec: the HDA codec
- * @nid: NID to parse
- * @conn_list: connection list array
- * @max_conns: max. number of connections to store
- *
- * Parses the connection list of the given widget and stores the list
- * of NIDs.
- *
- * Returns the number of connections, or a negative error code.
- */
-int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
-                             hda_nid_t *conn_list, int max_conns)
-{
-        const hda_nid_t *list;
-        int len = snd_hda_get_conn_list(codec, nid, &list);
-
-        if (len <= 0)
-                return len;
-        if (len > max_conns) {
-                snd_printk(KERN_ERR "hda_codec: "
-                           "Too many connections %d for NID 0x%x\n",
-                           len, nid);
-                return -EINVAL;
-        }
-        memcpy(conn_list, list, len * sizeof(hda_nid_t));
-        return len;
-}
 EXPORT_SYMBOL_HDA(snd_hda_get_connections);
 
 /**
@@ -543,6 +532,7 @@ int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
         hda_nid_t *p;
         int i, old_used;
 
+        mutex_lock(&codec->hash_mutex);
         p = lookup_conn_list(array, nid);
         if (p)
                 *p = -1; /* invalidate the old entry */
@@ -553,10 +543,12 @@ int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int len,
         for (i = 0; i < len; i++)
                 if (!add_conn_list(array, list[i]))
                         goto error_add;
+        mutex_unlock(&codec->hash_mutex);
         return 0;
 
  error_add:
         array->used = old_used;
+        mutex_unlock(&codec->hash_mutex);
         return -ENOMEM;
 }
 EXPORT_SYMBOL_HDA(snd_hda_override_conn_list);
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 29a311b05f2d..54b52819fb47 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -911,10 +911,13 @@ int snd_hda_get_sub_nodes(struct hda_codec *codec, hda_nid_t nid,
                           hda_nid_t *start_id);
 int snd_hda_get_connections(struct hda_codec *codec, hda_nid_t nid,
                             hda_nid_t *conn_list, int max_conns);
+static inline int
+snd_hda_get_num_conns(struct hda_codec *codec, hda_nid_t nid)
+{
+        return snd_hda_get_connections(codec, nid, NULL, 0);
+}
 int snd_hda_get_raw_connections(struct hda_codec *codec, hda_nid_t nid,
                             hda_nid_t *conn_list, int max_conns);
-int snd_hda_get_conn_list(struct hda_codec *codec, hda_nid_t nid,
-                          const hda_nid_t **listp);
 int snd_hda_override_conn_list(struct hda_codec *codec, hda_nid_t nid, int nums,
                           const hda_nid_t *list);
 int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index 152f458afd2b..0d68bb0ff376 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -349,7 +349,7 @@ static int alc_mux_select(struct hda_codec *codec, unsigned int adc_idx,
         nid = get_capsrc(spec, adc_idx);
 
         /* no selection? */
-        num_conns = snd_hda_get_conn_list(codec, nid, NULL);
+        num_conns = snd_hda_get_num_conns(codec, nid);
         if (num_conns <= 1)
                 return 1;
 
@@ -2543,7 +2543,6 @@ static int alc_auto_fill_adc_caps(struct hda_codec *codec)
         nid = codec->start_nid;
         for (i = 0; i < codec->num_nodes; i++, nid++) {
                 hda_nid_t src;
-                const hda_nid_t *list;
                 unsigned int caps = get_wcaps(codec, nid);
                 int type = get_wcaps_type(caps);
 
@@ -2554,6 +2553,7 @@ static int alc_auto_fill_adc_caps(struct hda_codec *codec)
                 src = nid;
                 for (;;) {
                         int n;
+                        hda_nid_t conn_nid;
                         type = get_wcaps_type(get_wcaps(codec, src));
                         if (type == AC_WID_PIN)
                                 break;
@@ -2561,13 +2561,14 @@ static int alc_auto_fill_adc_caps(struct hda_codec *codec)
                                 cap_nids[nums] = src;
                                 break;
                         }
-                        n = snd_hda_get_conn_list(codec, src, &list);
+                        n = snd_hda_get_num_conns(codec, src);
                         if (n > 1) {
                                 cap_nids[nums] = src;
                                 break;
                         } else if (n != 1)
                                 break;
-                        src = *list;
+                        if (snd_hda_get_connections(codec, src, &src, 1) != 1)
+                                break;
                 }
                 if (++nums >= max_nums)
                         break;
@@ -2708,7 +2709,7 @@ static void alc_auto_init_analog_input(struct hda_codec *codec)
 
         /* mute all loopback inputs */
         if (spec->mixer_nid) {
-                int nums = snd_hda_get_conn_list(codec, spec->mixer_nid, NULL);
+                int nums = snd_hda_get_num_conns(codec, spec->mixer_nid);
                 for (i = 0; i < nums; i++)
                         snd_hda_codec_write(codec, spec->mixer_nid, 0,
                                             AC_VERB_SET_AMP_GAIN_MUTE,
@@ -3338,7 +3339,7 @@ static int alc_auto_add_sw_ctl(struct hda_codec *codec,
         if (wid_type == AC_WID_PIN || wid_type == AC_WID_AUD_OUT) {
                 type = ALC_CTL_WIDGET_MUTE;
                 val = HDA_COMPOSE_AMP_VAL(nid, chs, 0, HDA_OUTPUT);
-        } else if (snd_hda_get_conn_list(codec, nid, NULL) == 1) {
+        } else if (snd_hda_get_num_conns(codec, nid) == 1) {
                 type = ALC_CTL_WIDGET_MUTE;
                 val = HDA_COMPOSE_AMP_VAL(nid, chs, 0, HDA_INPUT);
         } else {
@@ -3898,7 +3899,7 @@ static void alc_remove_invalid_adc_nids(struct hda_codec *codec)
         nums = 0;
         for (n = 0; n < spec->num_adc_nids; n++) {
                 hda_nid_t cap = spec->private_capsrc_nids[n];
-                int num_conns = snd_hda_get_conn_list(codec, cap, NULL);
+                int num_conns = snd_hda_get_num_conns(codec, cap);
                 for (i = 0; i < imux->num_items; i++) {
                         hda_nid_t pin = spec->imux_pins[i];
                         if (pin) {
@@ -4027,7 +4028,7 @@ static void select_or_unmute_capsrc(struct hda_codec *codec, hda_nid_t cap,
         if (get_wcaps_type(get_wcaps(codec, cap)) == AC_WID_AUD_MIX) {
                 snd_hda_codec_amp_stereo(codec, cap, HDA_INPUT, idx,
                                          HDA_AMP_MUTE, 0);
-        } else if (snd_hda_get_conn_list(codec, cap, NULL) > 1) {
+        } else if (snd_hda_get_num_conns(codec, cap) > 1) {
                 snd_hda_codec_write_cache(codec, cap, 0,
                                           AC_VERB_SET_CONNECT_SEL, idx);
         }
diff --git a/sound/pci/hda/patch_via.c b/sound/pci/hda/patch_via.c
index db272fb5e579..82b368068e08 100644
--- a/sound/pci/hda/patch_via.c
+++ b/sound/pci/hda/patch_via.c
@@ -485,7 +485,7 @@ static void activate_output_mix(struct hda_codec *codec, struct nid_path *path,
 
         if (!path)
                 return;
-        num = snd_hda_get_conn_list(codec, mix_nid, NULL);
+        num = snd_hda_get_num_conns(codec, mix_nid);
         for (i = 0; i < num; i++) {
                 if (i == idx)
                         val = AMP_IN_UNMUTE(i);