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

Kees Cook
2024-07-08T19:18:41Z

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@kernel.org>
---
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: linux-hardening@vger.kernel.org
---
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