Skip to content

Commit

Permalink
ALSA: hda - Fix possible races of accesses to connection list array
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Takashi Iwai committed May 19, 2012
1 parent c882246 commit 09cf03b
Show file tree
Hide file tree
Showing 4 changed files with 52 additions and 56 deletions.
82 changes: 37 additions & 45 deletions sound/pci/hda/hda_codec.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);

/**
Expand Down Expand Up @@ -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 */
Expand All @@ -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);
Expand Down
7 changes: 5 additions & 2 deletions sound/pci/hda/hda_codec.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down
17 changes: 9 additions & 8 deletions sound/pci/hda/patch_realtek.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand Down Expand Up @@ -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);

Expand All @@ -2554,20 +2553,22 @@ 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;
if (type == AC_WID_AUD_SEL) {
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;
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
}
Expand Down
2 changes: 1 addition & 1 deletion sound/pci/hda/patch_via.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down

0 comments on commit 09cf03b

Please sign in to comment.