diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-30 09:22:00 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-30 09:22:00 -0700 |
| commit | 034dd340b08be1f2f0477ad16131d609f9dbd53c (patch) | |
| tree | 2536f4b2d7893ccd916b5abdf3c454ad6edc03c2 /crypto/hctr2.c | |
| download | linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.tar.gz linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.zip | |
Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted
Pull tracing fixes from Steven Rostedt:
- Fix error output of boot instance creation failure
Currently if a boot instance creation fails, instead of printing out
the name of the instance that failed, it prints "(null)". That is
because it prints "cur_str" that had already been processed by
strsep(). Print the saved name instead.
While at it, print the error code of the failure.
- Fix use-after-free for same named historgrams
Histograms can be named so that they can be used in multiple events.
But if the named histogram has a variable attached, the second event
that uses the named histogram which duplicates it and needs to free
the original after duplication leaves the old variable in place and
still visible. If another histogram uses than variable, it will use
the stale one which will try to reference the freed duplicate
histogram and crash the kernel.
Free the duplicate variables along with the duplicated histogram
data.
- Check return value of kthread_run() in event self test
The events self tests uses a kthread for testing but does not check
if it succeeded in creating a kthread. If the kthread creation were
to fail, the code will still try to call kthread_stop() on the error
returned.
- Fix race between reading trace_pipe and updating subbuffer size
If a user is reading the trace_pipe file at the same time they update
the ring buffer sub-buffer size, can cause the trace_pipe read to
read stale data. Add trace_access_lock() around updating the ring
buffer sub-buffer size.
- Fix eventfs_inode on failure path in creation of the events directory
In the creation of the "events" directory, if after allocating the
eventfs_inode a failure is detected, it calls cleanup_ei() which
calls free_ei(). The free_ei() will test if eventfs_inode being freed
has no children. It is a bug if it does. But on the failure case of
the creation of the "events" directory, the children lists have not
yet been initialized and the free will trigger a warning because
list_empty() on an uninitialized list returns false.
Move the initialization into init_ei() where it makes more sense and
makes sure that a created eventfs_inode has its lists initialized
upon creation.
- Check return value of kthread_run() in ftrace direct sample code
The sample code that shows how to use the ftrace direct calls does
not test the return of kthread_run() to see if it succeeds. Return a
failure if the kthread_run() doesn't succeed.
- Clear user events state on fork in case of alloc failure
On fork, the child gets a pointer to the parent's user events state.
It makes a copy of it then updates the child's pointer to it. But if
the allocation fails, the duplication function leaves the child with
a pointer to its parent's descriptor. When the child cleans up its
data, it will free the parent's descriptor while the parent is still
using it.
In the duplication function, set the child's user_event_mm to NULL
before testing if the allocation succeeded, and when it exits it will
not free the parent's descriptor.
- Fix retry exhaustion in simple ring buffer reader swap
simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
post-decrements it only after a failed link replacement. On the final
attempt, a successful replacement leaves retry at zero, while a
failed replacement leaves it at -1.
But the check for success expects the retry value to be non-zero and
exits with an error on zero. This is the opposite result. Fix it.
- Fail nicely when the remote swap_reader_page() returns an error
Currently, if the swap_reader_page() of a remote buffer fails, it
triggers a WARN_ON_ONCE() and continues normally. Instead, have it
exit with an error and a pr_warn() print instead of a full WARNING.
* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Stop remote reader update when page swap fails
tracing: Fix retry exhaustion in simple ring buffer reader swap
tracing/user_events: Clear copied tracing state before fork duplication
samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
eventfs: Initialize ei->children and ei->list in init_ei()
tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
tracing: Fix crash passing ERR_PTR to kthread_stop()
tracing: Fix use-after-free with same-name named triggers
tracing: Fix logged instance name on creation failure
Diffstat (limited to 'crypto/hctr2.c')
| -rw-r--r-- | crypto/hctr2.c | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/crypto/hctr2.c b/crypto/hctr2.c new file mode 100644 index 000000000..cfc2343bc --- /dev/null +++ b/crypto/hctr2.c @@ -0,0 +1,480 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HCTR2 length-preserving encryption mode + * + * Copyright 2021 Google LLC + */ + + +/* + * HCTR2 is a length-preserving encryption mode that is efficient on + * processors with instructions to accelerate AES and carryless + * multiplication, e.g. x86 processors with AES-NI and CLMUL, and ARM + * processors with the ARMv8 crypto extensions. + * + * For more details, see the paper: "Length-preserving encryption with HCTR2" + * (https://eprint.iacr.org/2021/1441.pdf) + */ + +#include <crypto/gf128hash.h> +#include <crypto/internal/cipher.h> +#include <crypto/internal/skcipher.h> +#include <crypto/scatterwalk.h> +#include <linux/module.h> + +#define BLOCKCIPHER_BLOCK_SIZE 16 + +/* + * The specification allows variable-length tweaks, but Linux's crypto API + * currently only allows algorithms to support a single length. The "natural" + * tweak length for HCTR2 is 16, since that fits into one POLYVAL block for + * the best performance. But longer tweaks are useful for fscrypt, to avoid + * needing to derive per-file keys. So instead we use two blocks, or 32 bytes. + */ +#define TWEAK_SIZE 32 + +struct hctr2_instance_ctx { + struct crypto_cipher_spawn blockcipher_spawn; + struct crypto_skcipher_spawn xctr_spawn; +}; + +struct hctr2_tfm_ctx { + struct crypto_cipher *blockcipher; + struct crypto_skcipher *xctr; + struct polyval_key poly_key; + struct polyval_elem hashed_tweaklens[2]; + u8 L[BLOCKCIPHER_BLOCK_SIZE]; +}; + +struct hctr2_request_ctx { + u8 first_block[BLOCKCIPHER_BLOCK_SIZE]; + u8 xctr_iv[BLOCKCIPHER_BLOCK_SIZE]; + struct scatterlist *bulk_part_dst; + struct scatterlist *bulk_part_src; + struct scatterlist sg_src[2]; + struct scatterlist sg_dst[2]; + struct polyval_elem hashed_tweak; + /* + * skcipher sub-request size is unknown at compile-time, so it needs to + * go after the members with known sizes. + */ + union { + struct polyval_ctx poly_ctx; + struct skcipher_request xctr_req; + } u; +}; + +/* + * The input data for each HCTR2 hash step begins with a 16-byte block that + * contains the tweak length and a flag that indicates whether the input is evenly + * divisible into blocks. Since this implementation only supports one tweak + * length, we precompute the two hash states resulting from hashing the two + * possible values of this initial block. This reduces by one block the amount of + * data that needs to be hashed for each encryption/decryption + * + * These precomputed hashes are stored in hctr2_tfm_ctx. + */ +static void hctr2_hash_tweaklens(struct hctr2_tfm_ctx *tctx) +{ + struct polyval_ctx ctx; + + for (int has_remainder = 0; has_remainder < 2; has_remainder++) { + const __le64 tweak_length_block[2] = { + cpu_to_le64(TWEAK_SIZE * 8 * 2 + 2 + has_remainder), + }; + + polyval_init(&ctx, &tctx->poly_key); + polyval_update(&ctx, (const u8 *)&tweak_length_block, + sizeof(tweak_length_block)); + static_assert(sizeof(tweak_length_block) == POLYVAL_BLOCK_SIZE); + polyval_export_blkaligned( + &ctx, &tctx->hashed_tweaklens[has_remainder]); + } + memzero_explicit(&ctx, sizeof(ctx)); +} + +static int hctr2_setkey(struct crypto_skcipher *tfm, const u8 *key, + unsigned int keylen) +{ + struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + u8 hbar[BLOCKCIPHER_BLOCK_SIZE]; + int err; + + crypto_cipher_clear_flags(tctx->blockcipher, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(tctx->blockcipher, + crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_MASK); + err = crypto_cipher_setkey(tctx->blockcipher, key, keylen); + if (err) + return err; + + crypto_skcipher_clear_flags(tctx->xctr, CRYPTO_TFM_REQ_MASK); + crypto_skcipher_set_flags(tctx->xctr, + crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_MASK); + err = crypto_skcipher_setkey(tctx->xctr, key, keylen); + if (err) + return err; + + memset(hbar, 0, sizeof(hbar)); + crypto_cipher_encrypt_one(tctx->blockcipher, hbar, hbar); + + memset(tctx->L, 0, sizeof(tctx->L)); + tctx->L[0] = 0x01; + crypto_cipher_encrypt_one(tctx->blockcipher, tctx->L, tctx->L); + + static_assert(sizeof(hbar) == POLYVAL_BLOCK_SIZE); + polyval_preparekey(&tctx->poly_key, hbar); + memzero_explicit(hbar, sizeof(hbar)); + + hctr2_hash_tweaklens(tctx); + return 0; +} + +static void hctr2_hash_tweak(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); + struct polyval_ctx *poly_ctx = &rctx->u.poly_ctx; + bool has_remainder = req->cryptlen % POLYVAL_BLOCK_SIZE; + + polyval_import_blkaligned(poly_ctx, &tctx->poly_key, + &tctx->hashed_tweaklens[has_remainder]); + polyval_update(poly_ctx, req->iv, TWEAK_SIZE); + + // Store the hashed tweak, since we need it when computing both + // H(T || N) and H(T || V). + static_assert(TWEAK_SIZE % POLYVAL_BLOCK_SIZE == 0); + polyval_export_blkaligned(poly_ctx, &rctx->hashed_tweak); +} + +static void hctr2_hash_message(struct skcipher_request *req, + struct scatterlist *sgl, + u8 digest[POLYVAL_DIGEST_SIZE]) +{ + static const u8 padding = 0x1; + struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); + struct polyval_ctx *poly_ctx = &rctx->u.poly_ctx; + const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE; + struct sg_mapping_iter miter; + int i; + int n = 0; + + sg_miter_start(&miter, sgl, sg_nents(sgl), + SG_MITER_FROM_SG | SG_MITER_ATOMIC); + for (i = 0; i < bulk_len; i += n) { + sg_miter_next(&miter); + n = min_t(unsigned int, miter.length, bulk_len - i); + polyval_update(poly_ctx, miter.addr, n); + } + sg_miter_stop(&miter); + + if (req->cryptlen % BLOCKCIPHER_BLOCK_SIZE) + polyval_update(poly_ctx, &padding, 1); + polyval_final(poly_ctx, digest); +} + +static int hctr2_finish(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); + struct polyval_ctx *poly_ctx = &rctx->u.poly_ctx; + u8 digest[POLYVAL_DIGEST_SIZE]; + + // U = UU ^ H(T || V) + // or M = MM ^ H(T || N) + polyval_import_blkaligned(poly_ctx, &tctx->poly_key, + &rctx->hashed_tweak); + hctr2_hash_message(req, rctx->bulk_part_dst, digest); + crypto_xor(rctx->first_block, digest, BLOCKCIPHER_BLOCK_SIZE); + + // Copy U (or M) into dst scatterlist + scatterwalk_map_and_copy(rctx->first_block, req->dst, + 0, BLOCKCIPHER_BLOCK_SIZE, 1); + return 0; +} + +static void hctr2_xctr_done(void *data, int err) +{ + struct skcipher_request *req = data; + + if (!err) + err = hctr2_finish(req); + + skcipher_request_complete(req, err); +} + +static int hctr2_crypt(struct skcipher_request *req, bool enc) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + const struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + struct hctr2_request_ctx *rctx = skcipher_request_ctx(req); + u8 digest[POLYVAL_DIGEST_SIZE]; + int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE; + + // Requests must be at least one block + if (req->cryptlen < BLOCKCIPHER_BLOCK_SIZE) + return -EINVAL; + + // Copy M (or U) into a temporary buffer + scatterwalk_map_and_copy(rctx->first_block, req->src, + 0, BLOCKCIPHER_BLOCK_SIZE, 0); + + // Create scatterlists for N and V + rctx->bulk_part_src = scatterwalk_ffwd(rctx->sg_src, req->src, + BLOCKCIPHER_BLOCK_SIZE); + rctx->bulk_part_dst = scatterwalk_ffwd(rctx->sg_dst, req->dst, + BLOCKCIPHER_BLOCK_SIZE); + + // MM = M ^ H(T || N) + // or UU = U ^ H(T || V) + hctr2_hash_tweak(req); + hctr2_hash_message(req, rctx->bulk_part_src, digest); + crypto_xor(digest, rctx->first_block, BLOCKCIPHER_BLOCK_SIZE); + + // UU = E(MM) + // or MM = D(UU) + if (enc) + crypto_cipher_encrypt_one(tctx->blockcipher, rctx->first_block, + digest); + else + crypto_cipher_decrypt_one(tctx->blockcipher, rctx->first_block, + digest); + + // S = MM ^ UU ^ L + crypto_xor(digest, rctx->first_block, BLOCKCIPHER_BLOCK_SIZE); + crypto_xor_cpy(rctx->xctr_iv, digest, tctx->L, BLOCKCIPHER_BLOCK_SIZE); + + // V = XCTR(S, N) + // or N = XCTR(S, V) + skcipher_request_set_tfm(&rctx->u.xctr_req, tctx->xctr); + skcipher_request_set_crypt(&rctx->u.xctr_req, rctx->bulk_part_src, + rctx->bulk_part_dst, bulk_len, + rctx->xctr_iv); + skcipher_request_set_callback(&rctx->u.xctr_req, + req->base.flags, + hctr2_xctr_done, req); + return crypto_skcipher_encrypt(&rctx->u.xctr_req) ?: + hctr2_finish(req); +} + +static int hctr2_encrypt(struct skcipher_request *req) +{ + return hctr2_crypt(req, true); +} + +static int hctr2_decrypt(struct skcipher_request *req) +{ + return hctr2_crypt(req, false); +} + +static int hctr2_init_tfm(struct crypto_skcipher *tfm) +{ + struct skcipher_instance *inst = skcipher_alg_instance(tfm); + struct hctr2_instance_ctx *ictx = skcipher_instance_ctx(inst); + struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + struct crypto_skcipher *xctr; + struct crypto_cipher *blockcipher; + int err; + + xctr = crypto_spawn_skcipher(&ictx->xctr_spawn); + if (IS_ERR(xctr)) + return PTR_ERR(xctr); + + blockcipher = crypto_spawn_cipher(&ictx->blockcipher_spawn); + if (IS_ERR(blockcipher)) { + err = PTR_ERR(blockcipher); + goto err_free_xctr; + } + + tctx->xctr = xctr; + tctx->blockcipher = blockcipher; + + BUILD_BUG_ON(offsetofend(struct hctr2_request_ctx, u) != + sizeof(struct hctr2_request_ctx)); + crypto_skcipher_set_reqsize( + tfm, max(sizeof(struct hctr2_request_ctx), + offsetofend(struct hctr2_request_ctx, u.xctr_req) + + crypto_skcipher_reqsize(xctr))); + return 0; + +err_free_xctr: + crypto_free_skcipher(xctr); + return err; +} + +static void hctr2_exit_tfm(struct crypto_skcipher *tfm) +{ + struct hctr2_tfm_ctx *tctx = crypto_skcipher_ctx(tfm); + + crypto_free_cipher(tctx->blockcipher); + crypto_free_skcipher(tctx->xctr); +} + +static void hctr2_free_instance(struct skcipher_instance *inst) +{ + struct hctr2_instance_ctx *ictx = skcipher_instance_ctx(inst); + + crypto_drop_cipher(&ictx->blockcipher_spawn); + crypto_drop_skcipher(&ictx->xctr_spawn); + kfree(inst); +} + +static int hctr2_create_common(struct crypto_template *tmpl, struct rtattr **tb, + const char *xctr_name) +{ + struct skcipher_alg_common *xctr_alg; + u32 mask; + struct skcipher_instance *inst; + struct hctr2_instance_ctx *ictx; + struct crypto_alg *blockcipher_alg; + char blockcipher_name[CRYPTO_MAX_ALG_NAME]; + int len; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask); + if (err) + return err; + + inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL); + if (!inst) + return -ENOMEM; + ictx = skcipher_instance_ctx(inst); + + /* Stream cipher, xctr(block_cipher) */ + err = crypto_grab_skcipher(&ictx->xctr_spawn, + skcipher_crypto_instance(inst), + xctr_name, 0, mask); + if (err) + goto err_free_inst; + xctr_alg = crypto_spawn_skcipher_alg_common(&ictx->xctr_spawn); + + err = -EINVAL; + if (strncmp(xctr_alg->base.cra_name, "xctr(", 5)) + goto err_free_inst; + len = strscpy(blockcipher_name, xctr_alg->base.cra_name + 5); + if (len < 1) + goto err_free_inst; + if (blockcipher_name[len - 1] != ')') + goto err_free_inst; + blockcipher_name[len - 1] = 0; + + /* Block cipher, e.g. "aes" */ + err = crypto_grab_cipher(&ictx->blockcipher_spawn, + skcipher_crypto_instance(inst), + blockcipher_name, 0, mask); + if (err) + goto err_free_inst; + blockcipher_alg = crypto_spawn_cipher_alg(&ictx->blockcipher_spawn); + + /* Require blocksize of 16 bytes */ + err = -EINVAL; + if (blockcipher_alg->cra_blocksize != BLOCKCIPHER_BLOCK_SIZE) + goto err_free_inst; + + /* Instance fields */ + + err = -ENAMETOOLONG; + if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, "hctr2(%s)", + blockcipher_alg->cra_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, + "hctr2_base(%s,polyval-lib)", + xctr_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + inst->alg.base.cra_blocksize = BLOCKCIPHER_BLOCK_SIZE; + inst->alg.base.cra_ctxsize = sizeof(struct hctr2_tfm_ctx); + inst->alg.base.cra_alignmask = xctr_alg->base.cra_alignmask; + inst->alg.base.cra_priority = (2 * xctr_alg->base.cra_priority + + blockcipher_alg->cra_priority) / + 3; + + inst->alg.setkey = hctr2_setkey; + inst->alg.encrypt = hctr2_encrypt; + inst->alg.decrypt = hctr2_decrypt; + inst->alg.init = hctr2_init_tfm; + inst->alg.exit = hctr2_exit_tfm; + inst->alg.min_keysize = xctr_alg->min_keysize; + inst->alg.max_keysize = xctr_alg->max_keysize; + inst->alg.ivsize = TWEAK_SIZE; + + inst->free = hctr2_free_instance; + + err = skcipher_register_instance(tmpl, inst); + if (err) { +err_free_inst: + hctr2_free_instance(inst); + } + return err; +} + +static int hctr2_create_base(struct crypto_template *tmpl, struct rtattr **tb) +{ + const char *xctr_name; + const char *polyval_name; + + xctr_name = crypto_attr_alg_name(tb[1]); + if (IS_ERR(xctr_name)) + return PTR_ERR(xctr_name); + + polyval_name = crypto_attr_alg_name(tb[2]); + if (IS_ERR(polyval_name)) + return PTR_ERR(polyval_name); + if (strcmp(polyval_name, "polyval") != 0 && + strcmp(polyval_name, "polyval-lib") != 0) + return -ENOENT; + + return hctr2_create_common(tmpl, tb, xctr_name); +} + +static int hctr2_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + const char *blockcipher_name; + char xctr_name[CRYPTO_MAX_ALG_NAME]; + + blockcipher_name = crypto_attr_alg_name(tb[1]); + if (IS_ERR(blockcipher_name)) + return PTR_ERR(blockcipher_name); + + if (snprintf(xctr_name, CRYPTO_MAX_ALG_NAME, "xctr(%s)", + blockcipher_name) >= CRYPTO_MAX_ALG_NAME) + return -ENAMETOOLONG; + + return hctr2_create_common(tmpl, tb, xctr_name); +} + +static struct crypto_template hctr2_tmpls[] = { + { + /* hctr2_base(xctr_name, polyval_name) */ + .name = "hctr2_base", + .create = hctr2_create_base, + .module = THIS_MODULE, + }, { + /* hctr2(blockcipher_name) */ + .name = "hctr2", + .create = hctr2_create, + .module = THIS_MODULE, + } +}; + +static int __init hctr2_module_init(void) +{ + return crypto_register_templates(hctr2_tmpls, ARRAY_SIZE(hctr2_tmpls)); +} + +static void __exit hctr2_module_exit(void) +{ + return crypto_unregister_templates(hctr2_tmpls, + ARRAY_SIZE(hctr2_tmpls)); +} + +module_init(hctr2_module_init); +module_exit(hctr2_module_exit); + +MODULE_DESCRIPTION("HCTR2 length-preserving encryption mode"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS_CRYPTO("hctr2"); +MODULE_IMPORT_NS("CRYPTO_INTERNAL"); |
