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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /fs/verity/hash_algs.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'fs/verity/hash_algs.c')
-rw-r--r--fs/verity/hash_algs.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/fs/verity/hash_algs.c b/fs/verity/hash_algs.c
new file mode 100644
index 000000000..de53e14c8
--- /dev/null
+++ b/fs/verity/hash_algs.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs-verity hash algorithms
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include "fsverity_private.h"
+
+/* The hash algorithms supported by fs-verity */
+const struct fsverity_hash_alg fsverity_hash_algs[] = {
+ [FS_VERITY_HASH_ALG_SHA256] = {
+ .name = "sha256",
+ .digest_size = SHA256_DIGEST_SIZE,
+ .block_size = SHA256_BLOCK_SIZE,
+ .algo_id = HASH_ALGO_SHA256,
+ },
+ [FS_VERITY_HASH_ALG_SHA512] = {
+ .name = "sha512",
+ .digest_size = SHA512_DIGEST_SIZE,
+ .block_size = SHA512_BLOCK_SIZE,
+ .algo_id = HASH_ALGO_SHA512,
+ },
+};
+
+/**
+ * fsverity_get_hash_alg() - get a hash algorithm by number
+ * @inode: optional inode for logging purposes
+ * @num: the hash algorithm number
+ *
+ * Get the struct fsverity_hash_alg for the given hash algorithm number.
+ *
+ * Return: pointer to the hash alg if it's known, otherwise NULL.
+ */
+const struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
+ unsigned int num)
+{
+ if (num >= ARRAY_SIZE(fsverity_hash_algs) ||
+ !fsverity_hash_algs[num].name) {
+ fsverity_warn(inode, "Unknown hash algorithm number: %u", num);
+ return NULL;
+ }
+ return &fsverity_hash_algs[num];
+}
+
+/**
+ * fsverity_prepare_hash_state() - precompute the initial hash state
+ * @alg: hash algorithm
+ * @salt: a salt which is to be prepended to all data to be hashed
+ * @salt_size: salt size in bytes
+ *
+ * Return: the kmalloc()'ed initial hash state, or NULL if out of memory.
+ */
+union fsverity_hash_ctx *
+fsverity_prepare_hash_state(const struct fsverity_hash_alg *alg,
+ const u8 *salt, size_t salt_size)
+{
+ u8 *padded_salt = NULL;
+ size_t padded_salt_size;
+ union fsverity_hash_ctx ctx;
+ void *res = NULL;
+
+ /*
+ * Zero-pad the salt to the next multiple of the input size of the hash
+ * algorithm's compression function, e.g. 64 bytes for SHA-256 or 128
+ * bytes for SHA-512. This ensures that the hash algorithm won't have
+ * any bytes buffered internally after processing the salt, thus making
+ * salted hashing just as fast as unsalted hashing.
+ */
+ padded_salt_size = round_up(salt_size, alg->block_size);
+ padded_salt = kzalloc(padded_salt_size, GFP_KERNEL);
+ if (!padded_salt)
+ return NULL;
+ memcpy(padded_salt, salt, salt_size);
+
+ switch (alg->algo_id) {
+ case HASH_ALGO_SHA256:
+ sha256_init(&ctx.sha256);
+ sha256_update(&ctx.sha256, padded_salt, padded_salt_size);
+ res = kmemdup(&ctx.sha256, sizeof(ctx.sha256), GFP_KERNEL);
+ break;
+ case HASH_ALGO_SHA512:
+ sha512_init(&ctx.sha512);
+ sha512_update(&ctx.sha512, padded_salt, padded_salt_size);
+ res = kmemdup(&ctx.sha512, sizeof(ctx.sha512), GFP_KERNEL);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ kfree(padded_salt);
+ return res;
+}
+
+/**
+ * fsverity_hash_block() - hash a single data or hash block
+ * @params: the Merkle tree's parameters
+ * @data: virtual address of a buffer containing the block to hash
+ * @out: output digest, size 'params->digest_size' bytes
+ *
+ * Hash a single data or hash block. The hash is salted if a salt is specified
+ * in the Merkle tree parameters.
+ */
+void fsverity_hash_block(const struct merkle_tree_params *params,
+ const void *data, u8 *out)
+{
+ union fsverity_hash_ctx ctx;
+
+ if (!params->hashstate) {
+ fsverity_hash_buffer(params->hash_alg, data, params->block_size,
+ out);
+ return;
+ }
+
+ switch (params->hash_alg->algo_id) {
+ case HASH_ALGO_SHA256:
+ ctx.sha256 = params->hashstate->sha256;
+ sha256_update(&ctx.sha256, data, params->block_size);
+ sha256_final(&ctx.sha256, out);
+ return;
+ case HASH_ALGO_SHA512:
+ ctx.sha512 = params->hashstate->sha512;
+ sha512_update(&ctx.sha512, data, params->block_size);
+ sha512_final(&ctx.sha512, out);
+ return;
+ default:
+ BUG();
+ }
+}
+
+/**
+ * fsverity_hash_buffer() - hash some data
+ * @alg: the hash algorithm to use
+ * @data: the data to hash
+ * @size: size of data to hash, in bytes
+ * @out: output digest, size 'alg->digest_size' bytes
+ */
+void fsverity_hash_buffer(const struct fsverity_hash_alg *alg,
+ const void *data, size_t size, u8 *out)
+{
+ switch (alg->algo_id) {
+ case HASH_ALGO_SHA256:
+ sha256(data, size, out);
+ return;
+ case HASH_ALGO_SHA512:
+ sha512(data, size, out);
+ return;
+ default:
+ BUG();
+ }
+}
+
+void __init fsverity_check_hash_algs(void)
+{
+ size_t i;
+
+ /*
+ * Sanity check the hash algorithms (could be a build-time check, but
+ * they're in an array)
+ */
+ for (i = 0; i < ARRAY_SIZE(fsverity_hash_algs); i++) {
+ const struct fsverity_hash_alg *alg = &fsverity_hash_algs[i];
+
+ if (!alg->name)
+ continue;
+
+ /*
+ * 0 must never be allocated as an FS_VERITY_HASH_ALG_* value,
+ * as it is reserved for users that use 0 to mean unspecified or
+ * a default value. fs/verity/ itself doesn't care and doesn't
+ * have a default algorithm, but some users make use of this.
+ */
+ BUG_ON(i == 0);
+
+ BUG_ON(alg->digest_size > FS_VERITY_MAX_DIGEST_SIZE);
+
+ /*
+ * For efficiency, the implementation currently assumes the
+ * digest and block sizes are powers of 2. This limitation can
+ * be lifted if the code is updated to handle other values.
+ */
+ BUG_ON(!is_power_of_2(alg->digest_size));
+ BUG_ON(!is_power_of_2(alg->block_size));
+
+ /* Verify that there is a valid mapping to HASH_ALGO_*. */
+ BUG_ON(alg->algo_id == 0);
+ BUG_ON(alg->digest_size != hash_digest_size[alg->algo_id]);
+ }
+}