ALSA: oss: Relax __free() variable declarations

We used to have a variable declaration with __free() initialized with
NULL.  This was to keep the old coding style rule, but recently it's
relaxed and rather recommends to follow the new rule to declare in
place of use for __free() -- which avoids potential deadlocks or UAFs
with nested cleanups.

Although the current code has no bug, per se, let's follow the new
standard and move the declaration to the place of assignment (or
directly assign the allocated result) instead of NULL initializations.

Fixes: a55bc334d3df ("ALSA: pcm_oss: ump: Use automatic cleanup of kfree()")
Fixes: 6c40eec521af ("ALSA: mixer_oss: ump: Use automatic cleanup of kfree()")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20251216140634.171890-5-tiwai@suse.de

diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index e839a4bb93f819a42fcc87c5b0614a23e711da39..69422ab2d80861118d9e87452ef24c59fff6fde6 100644 (file)
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -517,8 +517,6 @@ static void snd_mixer_oss_get_volume1_vol(struct snd_mixer_oss_file *fmixer,
                                          unsigned int numid,
                                          int *left, int *right)
 {
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        struct snd_kcontrol *kctl;
        struct snd_card *card = fmixer->card;
 
@@ -528,8 +526,11 @@ static void snd_mixer_oss_get_volume1_vol(struct snd_mixer_oss_file *fmixer,
        kctl = snd_ctl_find_numid(card, numid);
        if (!kctl)
                return;
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return;
        if (kctl->info(kctl, uinfo))
@@ -550,8 +551,6 @@ static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
                                         int *left, int *right,
                                         int route)
 {
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        struct snd_kcontrol *kctl;
        struct snd_card *card = fmixer->card;
 
@@ -561,8 +560,11 @@ static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
        kctl = snd_ctl_find_numid(card, numid);
        if (!kctl)
                return;
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return;
        if (kctl->info(kctl, uinfo))
@@ -609,8 +611,6 @@ static void snd_mixer_oss_put_volume1_vol(struct snd_mixer_oss_file *fmixer,
                                          unsigned int numid,
                                          int left, int right)
 {
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        struct snd_kcontrol *kctl;
        struct snd_card *card = fmixer->card;
        int res;
@@ -621,8 +621,11 @@ static void snd_mixer_oss_put_volume1_vol(struct snd_mixer_oss_file *fmixer,
        kctl = snd_ctl_find_numid(card, numid);
        if (!kctl)
                return;
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return;
        if (kctl->info(kctl, uinfo))
@@ -646,8 +649,6 @@ static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
                                         int left, int right,
                                         int route)
 {
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        struct snd_kcontrol *kctl;
        struct snd_card *card = fmixer->card;
        int res;
@@ -658,8 +659,11 @@ static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
        kctl = snd_ctl_find_numid(card, numid);
        if (!kctl)
                return;
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return;
        if (kctl->info(kctl, uinfo))
@@ -783,12 +787,12 @@ static int snd_mixer_oss_get_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
        struct snd_kcontrol *kctl;
        struct snd_mixer_oss_slot *pslot;
        struct slot *slot;
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        int err, idx;
        
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return -ENOMEM;
        guard(rwsem_read)(&card->controls_rwsem);
@@ -825,13 +829,13 @@ static int snd_mixer_oss_put_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
        struct snd_kcontrol *kctl;
        struct snd_mixer_oss_slot *pslot;
        struct slot *slot = NULL;
-       struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
-       struct snd_ctl_elem_value *uctl __free(kfree) = NULL;
        int err;
        unsigned int idx;
 
-       uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-       uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
+       struct snd_ctl_elem_info *uinfo __free(kfree) =
+               kzalloc(sizeof(*uinfo), GFP_KERNEL);
+       struct snd_ctl_elem_value *uctl __free(kfree) =
+               kzalloc(sizeof(*uctl), GFP_KERNEL);
        if (uinfo == NULL || uctl == NULL)
                return -ENOMEM;
        guard(rwsem_read)(&card->controls_rwsem);
@@ -872,18 +876,18 @@ struct snd_mixer_oss_assign_table {
 
 static int snd_mixer_oss_build_test(struct snd_mixer_oss *mixer, struct slot *slot, const char *name, int index, int item)
 {
-       struct snd_ctl_elem_info *info __free(kfree) = NULL;
        struct snd_kcontrol *kcontrol;
        struct snd_card *card = mixer->card;
        int err;
 
+       struct snd_ctl_elem_info *info __free(kfree) =
+               kmalloc(sizeof(*info), GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
        scoped_guard(rwsem_read, &card->controls_rwsem) {
                kcontrol = snd_mixer_oss_test_id(mixer, name, index);
                if (kcontrol == NULL)
                        return 0;
-               info = kmalloc(sizeof(*info), GFP_KERNEL);
-               if (!info)
-                       return -ENOMEM;
                err = kcontrol->info(kcontrol, info);
                if (err < 0)
                        return err;
@@ -1006,9 +1010,9 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer,
        if (!ptr->index)
                kctl = snd_mixer_oss_test_id(mixer, "Capture Source", 0);
        if (kctl) {
-               struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
+               struct snd_ctl_elem_info *uinfo __free(kfree) =
+                       kzalloc(sizeof(*uinfo), GFP_KERNEL);
 
-               uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
                if (!uinfo)
                        return -ENOMEM;
                        

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index a82dd155e1d3a630a33d828c847f54fc3e925d31..1dffa8fdf429aaa116ff63c6d90e6269604b46d2 100644 (file)
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -377,7 +377,6 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm,
                                 snd_pcm_hw_param_t var, unsigned int best,
                                 int *dir)
 {
-       struct snd_pcm_hw_params *save __free(kfree) = NULL;
        int v;
        unsigned int saved_min;
        int last = 0;
@@ -397,19 +396,22 @@ static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm,
                maxdir = 1;
                max--;
        }
-       save = kmalloc(sizeof(*save), GFP_KERNEL);
+
+       struct snd_pcm_hw_params *save __free(kfree) =
+               kmalloc(sizeof(*save), GFP_KERNEL);
        if (save == NULL)
                return -ENOMEM;
        *save = *params;
        saved_min = min;
        min = snd_pcm_hw_param_min(pcm, params, var, min, &mindir);
        if (min >= 0) {
-               struct snd_pcm_hw_params *params1 __free(kfree) = NULL;
                if (max < 0)
                        goto _end;
                if ((unsigned int)min == saved_min && mindir == valdir)
                        goto _end;
-               params1 = kmalloc(sizeof(*params1), GFP_KERNEL);
+
+               struct snd_pcm_hw_params *params1 __free(kfree) =
+                       kmalloc(sizeof(*params1), GFP_KERNEL);
                if (params1 == NULL)
                        return -ENOMEM;
                *params1 = *save;
@@ -781,10 +783,10 @@ static int choose_rate(struct snd_pcm_substream *substream,
                       struct snd_pcm_hw_params *params, unsigned int best_rate)
 {
        const struct snd_interval *it;
-       struct snd_pcm_hw_params *save __free(kfree) = NULL;
        unsigned int rate, prev;
 
-       save = kmalloc(sizeof(*save), GFP_KERNEL);
+       struct snd_pcm_hw_params *save __free(kfree) =
+               kmalloc(sizeof(*save), GFP_KERNEL);
        if (save == NULL)
                return -ENOMEM;
        *save = *params;
@@ -1834,7 +1836,6 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file)
        struct snd_pcm_substream *substream;
        int err;
        int direct;
-       struct snd_pcm_hw_params *params __free(kfree) = NULL;
        unsigned int formats = 0;
        const struct snd_mask *format_mask;
        int fmt;
@@ -1854,7 +1855,9 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file)
                        AFMT_S32_LE | AFMT_S32_BE |
                        AFMT_S24_LE | AFMT_S24_BE |
                        AFMT_S24_PACKED;
-       params = kmalloc(sizeof(*params), GFP_KERNEL);
+
+       struct snd_pcm_hw_params *params __free(kfree) =
+               kmalloc(sizeof(*params), GFP_KERNEL);
        if (!params)
                return -ENOMEM;
        _snd_pcm_hw_params_any(params);