[PATCH v2] ALSA: gus: Fix memory leaks at memory allocator error paths

[PATCH v2] ALSA: gus: Fix memory leaks at memory allocator error paths

[Takashi Iwai]

When snd_gf1_mem_xalloc() returns NULL, the current code still leaves
the formerly allocated block.name string but returns an error
immediately.  This patch does code-refactoring to move the kstrdup()
call itself into snd_gf1_mem_xalloc() and deals with the resource free
in the helper code by itself for fixing those memory leaks.

Suggested-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20211213132444.22385-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/isa/gus/gus_mem.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/sound/isa/gus/gus_mem.c b/sound/isa/gus/gus_mem.c
index 5e3ff3137dd7..3e56c01c4544 100644
--- a/sound/isa/gus/gus_mem.c
+++ b/sound/isa/gus/gus_mem.c
@@ -24,8 +24,9 @@ void snd_gf1_mem_lock(struct snd_gf1_mem * alloc, int xup)
 	}
 }
 
-static struct snd_gf1_mem_block *snd_gf1_mem_xalloc(struct snd_gf1_mem * alloc,
-					       struct snd_gf1_mem_block * block)
+static struct snd_gf1_mem_block *
+snd_gf1_mem_xalloc(struct snd_gf1_mem *alloc, struct snd_gf1_mem_block *block,
+		   const char *name)
 {
 	struct snd_gf1_mem_block *pblock, *nblock;
 
@@ -33,6 +34,12 @@ static struct snd_gf1_mem_block *snd_gf1_mem_xalloc(struct snd_gf1_mem * alloc,
 	if (nblock == NULL)
 		return NULL;
 	*nblock = *block;
+	nblock->name = kstrdup(name, GFP_KERNEL);
+	if (!nblock->name) {
+		kfree(nblock);
+		return NULL;
+	}
+
 	pblock = alloc->first;
 	while (pblock) {
 		if (pblock->ptr > nblock->ptr) {
@@ -198,12 +205,7 @@ struct snd_gf1_mem_block *snd_gf1_mem_alloc(struct snd_gf1_mem * alloc, int owne
 	if (share_id != NULL)
 		memcpy(&block.share_id, share_id, sizeof(block.share_id));
 	block.owner = owner;
-	block.name = kstrdup(name, GFP_KERNEL);
-	if (block.name == NULL) {
-		snd_gf1_mem_lock(alloc, 1);
-		return NULL;
-	}
-	nblock = snd_gf1_mem_xalloc(alloc, &block);
+	nblock = snd_gf1_mem_xalloc(alloc, &block, name);
 	snd_gf1_mem_lock(alloc, 1);
 	return nblock;
 }
@@ -240,14 +242,12 @@ int snd_gf1_mem_init(struct snd_gus_card * gus)
 	if (gus->gf1.enh_mode) {
 		block.ptr = 0;
 		block.size = 1024;
-		block.name = kstrdup("InterWave LFOs", GFP_KERNEL);
-		if (block.name == NULL || snd_gf1_mem_xalloc(alloc, &block) == NULL)
+		if (!snd_gf1_mem_xalloc(alloc, &block, "InterWave LFOs"))
 			return -ENOMEM;
 	}
 	block.ptr = gus->gf1.default_voice_address;
 	block.size = 4;
-	block.name = kstrdup("Voice default (NULL's)", GFP_KERNEL);
-	if (block.name == NULL || snd_gf1_mem_xalloc(alloc, &block) == NULL)
+	if (!snd_gf1_mem_xalloc(alloc, &block, "Voice default (NULL's)"))
 		return -ENOMEM;
 #ifdef CONFIG_SND_DEBUG
 	snd_card_ro_proc_new(gus->card, "gusmem", gus, snd_gf1_mem_info_read);
-- 
2.31.1

Re: [PATCH v2] ALSA: gus: Fix memory leaks at memory allocator error paths

[Jaroslav Kysela]

On 13. 12. 21 15:15, Takashi Iwai wrote:
> When snd_gf1_mem_xalloc() returns NULL, the current code still leaves
> the formerly allocated block.name string but returns an error
> immediately.  This patch does code-refactoring to move the kstrdup()
> call itself into snd_gf1_mem_xalloc() and deals with the resource free
> in the helper code by itself for fixing those memory leaks.
> 
> Suggested-by: Jaroslav Kysela <perex@perex.cz>
> Link: https://lore.kernel.org/r/20211213132444.22385-2-tiwai@suse.de
> Signed-off-by: Takashi Iwai <tiwai@suse.de>

Reviewed-by: Jaroslav Kysela <perex@perex.cz>

Thanks.

				Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.