[PATCH 1/3] crypto: pass the flag CRYPTO_ALG_ALLOCATES_MEMORY

From: Mikulas Patocka
Date: Wed Jun 17 2020 - 11:09:45 EST

Introduce a new flag CRYPTO_ALG_ALLOCATES_MEMORY and pass it down the
crypto stack.

If the flag is set, then the crypto driver allocates memory in its request
routine. Such drivers are not suitable for disk encryption because
GFP_ATOMIC allocation can fail anytime (causing random I/O errors) and
GFP_KERNEL allocation can recurse into the block layer, causing a
deadlock.

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>

---
crypto/adiantum.c | 3 ++-
crypto/authenc.c | 5 +++--
crypto/authencesn.c | 5 +++--
crypto/ccm.c | 7 ++++---
crypto/chacha20poly1305.c | 5 +++--
crypto/cryptd.c | 9 ++++++---
crypto/ctr.c | 3 ++-
crypto/cts.c | 5 +++--
crypto/essiv.c | 5 +++--
crypto/gcm.c | 15 +++++++++------
crypto/geniv.c | 3 ++-
crypto/lrw.c | 5 +++--
crypto/rsa-pkcs1pad.c | 5 +++--
crypto/xts.c | 2 +-
include/crypto/algapi.h | 9 +++++++++
include/linux/crypto.h | 11 ++++++++++-
16 files changed, 66 insertions(+), 31 deletions(-)

Index: linux-2.6/include/linux/crypto.h
===================================================================
--- linux-2.6.orig/include/linux/crypto.h
+++ linux-2.6/include/linux/crypto.h
@@ -97,9 +97,18 @@
#define CRYPTO_ALG_OPTIONAL_KEY 0x00004000

/*
+ * The driver may allocate memory during request processing, so it shouldn't be
+ * used in cases where memory allocation failures aren't acceptable, such as
+ * during block device encryption.
+ */
+#define CRYPTO_ALG_ALLOCATES_MEMORY 0x00008000
+
+/*
* Don't trigger module loading
*/
-#define CRYPTO_NOLOAD 0x00008000
+#define CRYPTO_NOLOAD 0x00010000
+
+#define CRYPTO_ALG_INHERITED_FLAGS (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY)

/*
* Transform masks and values (for crt_flags).
Index: linux-2.6/crypto/authenc.c
===================================================================
--- linux-2.6.orig/crypto/authenc.c
+++ linux-2.6/crypto/authenc.c
@@ -388,7 +388,8 @@ static int crypto_authenc_create(struct
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -424,7 +425,7 @@ static int crypto_authenc_create(struct
goto err_free_inst;

inst->alg.base.cra_flags = (auth_base->cra_flags |
- enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
+ enc->base.cra_flags) & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
auth_base->cra_priority;
inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
Index: linux-2.6/crypto/authencesn.c
===================================================================
--- linux-2.6.orig/crypto/authencesn.c
+++ linux-2.6/crypto/authencesn.c
@@ -406,7 +406,8 @@ static int crypto_authenc_esn_create(str
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -438,7 +439,7 @@ static int crypto_authenc_esn_create(str
goto err_free_inst;

inst->alg.base.cra_flags = (auth_base->cra_flags |
- enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
+ enc->base.cra_flags) & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
auth_base->cra_priority;
inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
Index: linux-2.6/crypto/ccm.c
===================================================================
--- linux-2.6.orig/crypto/ccm.c
+++ linux-2.6/crypto/ccm.c
@@ -462,7 +462,8 @@ static int crypto_ccm_create_common(stru
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
if (!inst)
@@ -507,7 +508,7 @@ static int crypto_ccm_create_common(stru
mac->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;

- inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = (mac->base.cra_priority +
ctr->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
@@ -759,7 +760,7 @@ static int crypto_rfc4309_create(struct
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
Index: linux-2.6/crypto/chacha20poly1305.c
===================================================================
--- linux-2.6.orig/crypto/chacha20poly1305.c
+++ linux-2.6/crypto/chacha20poly1305.c
@@ -573,7 +573,8 @@ static int chachapoly_create(struct cryp
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -614,7 +615,7 @@ static int chachapoly_create(struct cryp
goto err_free_inst;

inst->alg.base.cra_flags = (chacha->base.cra_flags |
- poly->base.cra_flags) & CRYPTO_ALG_ASYNC;
+ poly->base.cra_flags) & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = (chacha->base.cra_priority +
poly->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
Index: linux-2.6/crypto/cryptd.c
===================================================================
--- linux-2.6.orig/crypto/cryptd.c
+++ linux-2.6/crypto/cryptd.c
@@ -396,7 +396,8 @@ static int cryptd_create_skcipher(struct
goto err_free_inst;

inst->alg.base.cra_flags = CRYPTO_ALG_ASYNC |
- (alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
+ (alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS) |
+ (alg->base.cra_flags & CRYPTO_ALG_INTERNAL);

inst->alg.ivsize = crypto_skcipher_alg_ivsize(alg);
inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
@@ -663,7 +664,8 @@ static int cryptd_create_hash(struct cry

inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
(alg->base.cra_flags & (CRYPTO_ALG_INTERNAL |
- CRYPTO_ALG_OPTIONAL_KEY));
+ CRYPTO_ALG_OPTIONAL_KEY |
+ CRYPTO_ALG_INHERITED_FLAGS));

inst->alg.halg.digestsize = alg->digestsize;
inst->alg.halg.statesize = alg->statesize;
@@ -849,7 +851,8 @@ static int cryptd_create_aead(struct cry
goto err_free_inst;

inst->alg.base.cra_flags = CRYPTO_ALG_ASYNC |
- (alg->base.cra_flags & CRYPTO_ALG_INTERNAL);
+ (alg->base.cra_flags & CRYPTO_ALG_INTERNAL) |
+ (alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS);
inst->alg.base.cra_ctxsize = sizeof(struct cryptd_aead_ctx);

inst->alg.ivsize = crypto_aead_alg_ivsize(alg);
Index: linux-2.6/crypto/ctr.c
===================================================================
--- linux-2.6.orig/crypto/ctr.c
+++ linux-2.6/crypto/ctr.c
@@ -276,6 +276,7 @@ static int crypto_rfc3686_create(struct
return -ENOMEM;

mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask) |
crypto_requires_off(algt->type, algt->mask,
CRYPTO_ALG_NEED_FALLBACK);

@@ -310,7 +311,7 @@ static int crypto_rfc3686_create(struct
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;

inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
Index: linux-2.6/crypto/cts.c
===================================================================
--- linux-2.6.orig/crypto/cts.c
+++ linux-2.6/crypto/cts.c
@@ -337,7 +337,8 @@ static int crypto_cts_create(struct cryp
if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
@@ -364,7 +365,7 @@ static int crypto_cts_create(struct cryp
if (err)
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
Index: linux-2.6/crypto/essiv.c
===================================================================
--- linux-2.6.orig/crypto/essiv.c
+++ linux-2.6/crypto/essiv.c
@@ -468,7 +468,8 @@ static int essiv_create(struct crypto_te
return PTR_ERR(shash_name);

type = algt->type & algt->mask;
- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

switch (type) {
case CRYPTO_ALG_TYPE_SKCIPHER:
@@ -559,7 +560,7 @@ static int essiv_create(struct crypto_te
hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto out_free_hash;

- base->cra_flags = block_base->cra_flags & CRYPTO_ALG_ASYNC;
+ base->cra_flags = block_base->cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
base->cra_blocksize = block_base->cra_blocksize;
base->cra_ctxsize = sizeof(struct essiv_tfm_ctx);
base->cra_alignmask = block_base->cra_alignmask;
Index: linux-2.6/crypto/gcm.c
===================================================================
--- linux-2.6.orig/crypto/gcm.c
+++ linux-2.6/crypto/gcm.c
@@ -593,7 +593,8 @@ static int crypto_gcm_create_common(stru
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -636,7 +637,7 @@ static int crypto_gcm_create_common(stru
goto err_free_inst;

inst->alg.base.cra_flags = (ghash->base.cra_flags |
- ctr->base.cra_flags) & CRYPTO_ALG_ASYNC;
+ ctr->base.cra_flags) & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = (ghash->base.cra_priority +
ctr->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
@@ -849,7 +850,8 @@ static int crypto_rfc4106_create(struct
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
@@ -882,7 +884,7 @@ static int crypto_rfc4106_create(struct
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
@@ -1071,7 +1073,8 @@ static int crypto_rfc4543_create(struct
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -1104,7 +1107,7 @@ static int crypto_rfc4543_create(struct
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
Index: linux-2.6/crypto/geniv.c
===================================================================
--- linux-2.6.orig/crypto/geniv.c
+++ linux-2.6/crypto/geniv.c
@@ -64,6 +64,7 @@ struct aead_instance *aead_geniv_alloc(s

/* Ignore async algorithms if necessary. */
mask |= crypto_requires_sync(algt->type, algt->mask);
+ mask |= crypto_requires_nomem(algt->type, algt->mask);

err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), type, mask);
@@ -89,7 +90,7 @@ struct aead_instance *aead_geniv_alloc(s
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
Index: linux-2.6/crypto/lrw.c
===================================================================
--- linux-2.6.orig/crypto/lrw.c
+++ linux-2.6/crypto/lrw.c
@@ -311,7 +311,8 @@ static int create(struct crypto_template
if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
@@ -379,7 +380,7 @@ static int create(struct crypto_template
} else
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
Index: linux-2.6/crypto/rsa-pkcs1pad.c
===================================================================
--- linux-2.6.orig/crypto/rsa-pkcs1pad.c
+++ linux-2.6/crypto/rsa-pkcs1pad.c
@@ -611,7 +611,8 @@ static int pkcs1pad_create(struct crypto
if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
@@ -658,7 +659,7 @@ static int pkcs1pad_create(struct crypto
goto err_free_inst;
}

- inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);

Index: linux-2.6/crypto/xts.c
===================================================================
--- linux-2.6.orig/crypto/xts.c
+++ linux-2.6/crypto/xts.c
@@ -415,7 +415,7 @@ static int create(struct crypto_template
} else
goto err_free_inst;

- inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
Index: linux-2.6/include/crypto/algapi.h
===================================================================
--- linux-2.6.orig/include/crypto/algapi.h
+++ linux-2.6/include/crypto/algapi.h
@@ -247,6 +247,15 @@ static inline int crypto_requires_sync(u
return crypto_requires_off(type, mask, CRYPTO_ALG_ASYNC);
}

+/*
+ * Returns CRYPTO_ALG_ALLOCATES_MEMORY if type/mask requires the use of drivers
+ * that don't allocate memory. Otherwise returns zero.
+ */
+static inline int crypto_requires_nomem(u32 type, u32 mask)
+{
+ return crypto_requires_off(type, mask, CRYPTO_ALG_ALLOCATES_MEMORY);
+}
+
noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size);

/**
Index: linux-2.6/crypto/adiantum.c
===================================================================
--- linux-2.6.orig/crypto/adiantum.c
+++ linux-2.6/crypto/adiantum.c
@@ -507,7 +507,8 @@ static int adiantum_create(struct crypto
if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
return -EINVAL;

- mask = crypto_requires_sync(algt->type, algt->mask);
+ mask = crypto_requires_sync(algt->type, algt->mask) |
+ crypto_requires_nomem(algt->type, algt->mask);

inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
if (!inst)