[RFC][PATCH 4/4] pstore: Replace classic kmalloc code pattern with typed argument

[Kees Cook <kees@xxxxxxxxxx>]

Using a short Coccinelle script, it is possible to replace the classic
kmalloc code patterns with the typed information:

@alloc@
type TYPE;
TYPE *P;
expression GFP;
identifier ALLOC =~ "k[mz]alloc";
@@

	P = ALLOC(
-		\(sizeof(*P)\|sizeof(TYPE)\), GFP)
+		P, GFP)

Show this just for kmalloc/kzalloc usage in fs/pstore as an example.

Doing this for all allocator calls in the kernel touches much more:

 11941 files changed, 22459 insertions(+), 22345 deletions(-)

And obviously requires some more wrappers for kv*alloc, devm_*alloc,
etc.

Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
---
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: "Guilherme G. Piccoli" <gpiccoli@xxxxxxxxxx>
Cc: linux-hardening@xxxxxxxxxxxxxxx
---
 fs/pstore/blk.c      | 2 +-
 fs/pstore/platform.c | 2 +-
 fs/pstore/ram.c      | 3 +--
 fs/pstore/ram_core.c | 2 +-
 fs/pstore/zone.c     | 2 +-
 5 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index de8cf5d75f34..7bb9cacb380f 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -297,7 +297,7 @@ static int __init __best_effort_init(void)
 		return -EINVAL;
 	}
 
-	best_effort_dev = kzalloc(sizeof(*best_effort_dev), GFP_KERNEL);
+	best_effort_dev = kzalloc(best_effort_dev, GFP_KERNEL);
 	if (!best_effort_dev)
 		return -ENOMEM;
 
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 03425928d2fb..4e527c3ea530 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -682,7 +682,7 @@ void pstore_get_backend_records(struct pstore_info *psi,
 		struct pstore_record *record;
 		int rc;
 
-		record = kzalloc(sizeof(*record), GFP_KERNEL);
+		record = kzalloc(record, GFP_KERNEL);
 		if (!record) {
 			pr_err("out of memory creating record\n");
 			break;
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index b1a455f42e93..a0665a98b135 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -228,8 +228,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 			 */
 			struct persistent_ram_zone *tmp_prz, *prz_next;
 
-			tmp_prz = kzalloc(sizeof(struct persistent_ram_zone),
-					  GFP_KERNEL);
+			tmp_prz = kzalloc(tmp_prz, GFP_KERNEL);
 			if (!tmp_prz)
 				return -ENOMEM;
 			prz = tmp_prz;
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index f1848cdd6d34..01ddf1be6c3a 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -588,7 +588,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;
 
-	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+	prz = kzalloc(prz, GFP_KERNEL);
 	if (!prz) {
 		pr_err("failed to allocate persistent ram zone\n");
 		goto err;
diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c
index 694db616663f..8df890bb4db9 100644
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -1165,7 +1165,7 @@ static struct pstore_zone *psz_init_zone(enum pstore_type_id type,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	zone = kzalloc(sizeof(struct pstore_zone), GFP_KERNEL);
+	zone = kzalloc(zone, GFP_KERNEL);
 	if (!zone)
 		return ERR_PTR(-ENOMEM);
 
-- 
2.34.1