A tfm's context holds the expanded key schedule, which a crash dump would capture.
Allocate tfms from the secret pool, so that their backing pages are marked by crash_memaction for the kdump kernel to wipe. The context is a flexible array at the end of struct crypto_tfm and the frontend's private data sits in front of the struct, so the whole allocation moves into the pool. Allocation cost increases by a bucket lookup in crash_memaction. Freeing is unchanged. Signed-off-by: Jan Sebastian Götte <[email protected]> Assisted-by: Claude Opus 5 <[email protected]> --- crypto/api.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/crypto/api.c b/crypto/api.c index 24227582cfcf..eba310f128dc 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -18,6 +18,7 @@ #include <linux/module.h> #include <linux/param.h> #include <linux/sched/signal.h> +#include <linux/secret_pool.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/completion.h> @@ -413,7 +414,7 @@ struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type, int err = -ENOMEM; tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask); - tfm = kzalloc(tfm_size, GFP_KERNEL); + tfm = secret_pool_zalloc(tfm_size, GFP_KERNEL); if (tfm == NULL) goto out_err; @@ -428,7 +429,7 @@ struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type, crypto_exit_ops(tfm); if (err == -EAGAIN) crypto_shoot_alg(alg); - kfree(tfm); + kfree_sensitive(tfm); out_err: tfm = ERR_PTR(err); out: @@ -502,7 +503,7 @@ void *crypto_create_tfm_node(struct crypto_alg *alg, int err; size = frontend->tfmsize + sizeof(*tfm) + frontend->extsize(alg); - mem = kzalloc_node(size, GFP_KERNEL, node); + mem = secret_pool_zalloc_node(size, GFP_KERNEL, node); if (!mem) return ERR_PTR(-ENOMEM); @@ -525,7 +526,7 @@ void *crypto_create_tfm_node(struct crypto_alg *alg, out_free_tfm: if (err == -EAGAIN) crypto_shoot_alg(alg); - kfree(mem); + kfree_sensitive(mem); mem = ERR_PTR(err); out: return mem; -- 2.55.0
