[PATCH v11 05/20] x86: Add early SHA-1 support for Secure Launch early measurements
From: Ross Philipson <hidden>
Date: 2024-09-13 20:11:29
Also in:
kexec, linux-crypto, linux-efi, linux-integrity, lkml
Subsystem:
crypto api, crypto library, library code, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Herbert Xu, "David S. Miller", Eric Biggers, Jason A. Donenfeld, Ard Biesheuvel, Andrew Morton, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: "Daniel P. Smith" <redacted>
Secure Launch is written to be compliant with the Intel TXT Measured Launch
Developer's Guide. The MLE Guide dictates that the system can be configured to
use both the SHA-1 and SHA-2 hashing algorithms.
Regardless of the preference towards SHA-2, if the firmware elected to start
with the SHA-1 and SHA-2 banks active and the dynamic launch was configured to
include SHA-1, Secure Launch is obligated to record measurements for all
algorithms requested in the launch configuration.
The user environment or the integrity management does not desire to use SHA-1,
it is free to just ignore the SHA-1 bank in any integrity operation with the
TPM. If there is a larger concern about the SHA-1 bank being active, it is free
to deliberately cap the SHA-1 PCRs, recording the event in the D-RTM log.
The SHA-1 code here has its origins in the code from the main kernel:
commit c4d5b9f ("crypto: sha1 - implement base layer for SHA-1")
A modified version of this code was introduced to the lib/crypto/sha1.c to bring
it in line with the SHA-256 code and allow it to be pulled into the setup kernel
in the same manner as SHA-256 is.
Signed-off-by: Daniel P. Smith <redacted>
Signed-off-by: Ross Philipson <redacted>
---
arch/x86/boot/compressed/Makefile | 2 +
arch/x86/boot/compressed/sha1.c | 6 +++
include/crypto/sha1.h | 1 +
lib/crypto/sha1.c | 81 +++++++++++++++++++++++++++++++
4 files changed, 90 insertions(+)
create mode 100644 arch/x86/boot/compressed/sha1.c
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index f2051644de94..7eb03afb841b 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile@@ -107,6 +107,8 @@ vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_mixed.o vmlinux-libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a +vmlinux-objs-$(CONFIG_SECURE_LAUNCH) += $(obj)/sha1.o + $(obj)/vmlinux: $(vmlinux-objs-y) $(vmlinux-libs-y) FORCE $(call if_changed,ld)
diff --git a/arch/x86/boot/compressed/sha1.c b/arch/x86/boot/compressed/sha1.c
new file mode 100644
index 000000000000..d754489941ac
--- /dev/null
+++ b/arch/x86/boot/compressed/sha1.c@@ -0,0 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2024 Apertus Solutions, LLC. + */ + +#include "../../../../lib/crypto/sha1.c"
diff --git a/include/crypto/sha1.h b/include/crypto/sha1.h
index 044ecea60ac8..d715dd5332e1 100644
--- a/include/crypto/sha1.h
+++ b/include/crypto/sha1.h@@ -42,5 +42,6 @@ extern int crypto_sha1_finup(struct shash_desc *desc, const u8 *data, #define SHA1_WORKSPACE_WORDS 16 void sha1_init(__u32 *buf); void sha1_transform(__u32 *digest, const char *data, __u32 *W); +void sha1(const u8 *data, unsigned int len, u8 *out); #endif /* _CRYPTO_SHA1_H */
diff --git a/lib/crypto/sha1.c b/lib/crypto/sha1.c
index 6d2922747cab..de11d22ebded 100644
--- a/lib/crypto/sha1.c
+++ b/lib/crypto/sha1.c@@ -137,5 +137,86 @@ void sha1_init(__u32 *buf) } EXPORT_SYMBOL(sha1_init); +static void __sha1_transform(u32 *digest, const char *data) +{ + u32 ws[SHA1_WORKSPACE_WORDS]; + + sha1_transform(digest, data, ws); + + /* Ensure local data for generating digest is cleared in all cases */ + memzero_explicit(ws, sizeof(ws)); +} + +static void sha1_update(struct sha1_state *sctx, const u8 *data, unsigned int len) +{ + unsigned int partial = sctx->count % SHA1_BLOCK_SIZE; + int blocks; + + sctx->count += len; + + if (unlikely((partial + len) < SHA1_BLOCK_SIZE)) + goto out; + + if (partial) { + int p = SHA1_BLOCK_SIZE - partial; + + memcpy(sctx->buffer + partial, data, p); + data += p; + len -= p; + + __sha1_transform(sctx->state, sctx->buffer); + } + + blocks = len / SHA1_BLOCK_SIZE; + len %= SHA1_BLOCK_SIZE; + + if (blocks) { + while (blocks--) { + __sha1_transform(sctx->state, data); + data += SHA1_BLOCK_SIZE; + } + } + partial = 0; + +out: + memcpy(sctx->buffer + partial, data, len); +} + +static void sha1_final(struct sha1_state *sctx, u8 *out) +{ + const int bit_offset = SHA1_BLOCK_SIZE - sizeof(__be64); + unsigned int partial = sctx->count % SHA1_BLOCK_SIZE; + __be64 *bits = (__be64 *)(sctx->buffer + bit_offset); + __be32 *digest = (__be32 *)out; + int i; + + sctx->buffer[partial++] = 0x80; + if (partial > bit_offset) { + memset(sctx->buffer + partial, 0x0, SHA1_BLOCK_SIZE - partial); + partial = 0; + + __sha1_transform(sctx->state, sctx->buffer); + } + + memset(sctx->buffer + partial, 0x0, bit_offset - partial); + *bits = cpu_to_be64(sctx->count << 3); + __sha1_transform(sctx->state, sctx->buffer); + + for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(__be32); i++) + put_unaligned_be32(sctx->state[i], digest++); + + *sctx = (struct sha1_state){}; +} + +void sha1(const u8 *data, unsigned int len, u8 *out) +{ + struct sha1_state sctx = {0}; + + sha1_init(sctx.state); + sha1_update(&sctx, data, len); + sha1_final(&sctx, out); +} +EXPORT_SYMBOL(sha1); + MODULE_DESCRIPTION("SHA-1 Algorithm"); MODULE_LICENSE("GPL");
--
2.39.3