From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- lib/crypto/sha1.c | 336 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 336 insertions(+) create mode 100644 lib/crypto/sha1.c (limited to 'lib/crypto/sha1.c') diff --git a/lib/crypto/sha1.c b/lib/crypto/sha1.c new file mode 100644 index 000000000..b687b89d9 --- /dev/null +++ b/lib/crypto/sha1.c @@ -0,0 +1,336 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SHA-1 and HMAC-SHA1 library functions + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "fips-sha.h" + +static const struct sha1_block_state sha1_iv = { + .h = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 }, +}; + +/* + * If you have 32 registers or more, the compiler can (and should) + * try to change the array[] accesses into registers. However, on + * machines with less than ~25 registers, that won't really work, + * and at least gcc will make an unholy mess of it. + * + * So to avoid that mess which just slows things down, we force + * the stores to memory to actually happen (we might be better off + * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as + * suggested by Artur Skawina - that will also make gcc unable to + * try to do the silly "optimize away loads" part because it won't + * see what the value will be). + * + * Ben Herrenschmidt reports that on PPC, the C version comes close + * to the optimized asm with this (ie on PPC you don't want that + * 'volatile', since there are lots of registers). + * + * On ARM we get the best code generation by forcing a full memory barrier + * between each SHA_ROUND, otherwise gcc happily get wild with spilling and + * the stack frame size simply explode and performance goes down the drain. + */ + +#ifdef CONFIG_X86 + #define setW(x, val) (*(volatile __u32 *)&W(x) = (val)) +#elif defined(CONFIG_ARM) + #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) +#else + #define setW(x, val) (W(x) = (val)) +#endif + +/* This "rolls" over the 512-bit array */ +#define W(x) (workspace[(x)&15]) + +/* + * Where do we get the source from? The first 16 iterations get it from + * the input data, the next mix it from the 512-bit array. + */ +#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t) +#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1) + +#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ + __u32 TEMP = input(t); setW(t, TEMP); \ + E += TEMP + rol32(A,5) + (fn) + (constant); \ + B = ror32(B, 2); \ + TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0) + +#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) +#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) +#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) +#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E ) +#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) + +#define SHA1_WORKSPACE_WORDS 16 + +static void sha1_block_generic(struct sha1_block_state *state, + const u8 data[SHA1_BLOCK_SIZE], + u32 workspace[SHA1_WORKSPACE_WORDS]) +{ + __u32 A, B, C, D, E; + unsigned int i = 0; + + A = state->h[0]; + B = state->h[1]; + C = state->h[2]; + D = state->h[3]; + E = state->h[4]; + + /* Round 1 - iterations 0-16 take their input from 'data' */ + for (; i < 16; ++i) + T_0_15(i, A, B, C, D, E); + + /* Round 1 - tail. Input from 512-bit mixing array */ + for (; i < 20; ++i) + T_16_19(i, A, B, C, D, E); + + /* Round 2 */ + for (; i < 40; ++i) + T_20_39(i, A, B, C, D, E); + + /* Round 3 */ + for (; i < 60; ++i) + T_40_59(i, A, B, C, D, E); + + /* Round 4 */ + for (; i < 80; ++i) + T_60_79(i, A, B, C, D, E); + + state->h[0] += A; + state->h[1] += B; + state->h[2] += C; + state->h[3] += D; + state->h[4] += E; +} + +static void __maybe_unused sha1_blocks_generic(struct sha1_block_state *state, + const u8 *data, size_t nblocks) +{ + u32 workspace[SHA1_WORKSPACE_WORDS]; + + do { + sha1_block_generic(state, data, workspace); + data += SHA1_BLOCK_SIZE; + } while (--nblocks); + + memzero_explicit(workspace, sizeof(workspace)); +} + +#ifdef CONFIG_CRYPTO_LIB_SHA1_ARCH +#include "sha1.h" /* $(SRCARCH)/sha1.h */ +#else +#define sha1_blocks sha1_blocks_generic +#endif + +void sha1_init(struct sha1_ctx *ctx) +{ + ctx->state = sha1_iv; + ctx->bytecount = 0; +} +EXPORT_SYMBOL_GPL(sha1_init); + +void sha1_update(struct sha1_ctx *ctx, const u8 *data, size_t len) +{ + size_t partial = ctx->bytecount % SHA1_BLOCK_SIZE; + + ctx->bytecount += len; + + if (partial + len >= SHA1_BLOCK_SIZE) { + size_t nblocks; + + if (partial) { + size_t l = SHA1_BLOCK_SIZE - partial; + + memcpy(&ctx->buf[partial], data, l); + data += l; + len -= l; + + sha1_blocks(&ctx->state, ctx->buf, 1); + } + + nblocks = len / SHA1_BLOCK_SIZE; + len %= SHA1_BLOCK_SIZE; + + if (nblocks) { + sha1_blocks(&ctx->state, data, nblocks); + data += nblocks * SHA1_BLOCK_SIZE; + } + partial = 0; + } + if (len) + memcpy(&ctx->buf[partial], data, len); +} +EXPORT_SYMBOL_GPL(sha1_update); + +static void __sha1_final(struct sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE]) +{ + u64 bitcount = ctx->bytecount << 3; + size_t partial = ctx->bytecount % SHA1_BLOCK_SIZE; + + ctx->buf[partial++] = 0x80; + if (partial > SHA1_BLOCK_SIZE - 8) { + memset(&ctx->buf[partial], 0, SHA1_BLOCK_SIZE - partial); + sha1_blocks(&ctx->state, ctx->buf, 1); + partial = 0; + } + memset(&ctx->buf[partial], 0, SHA1_BLOCK_SIZE - 8 - partial); + *(__be64 *)&ctx->buf[SHA1_BLOCK_SIZE - 8] = cpu_to_be64(bitcount); + sha1_blocks(&ctx->state, ctx->buf, 1); + + for (size_t i = 0; i < SHA1_DIGEST_SIZE; i += 4) + put_unaligned_be32(ctx->state.h[i / 4], out + i); +} + +void sha1_final(struct sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE]) +{ + __sha1_final(ctx, out); + memzero_explicit(ctx, sizeof(*ctx)); +} +EXPORT_SYMBOL_GPL(sha1_final); + +void sha1(const u8 *data, size_t len, u8 out[SHA1_DIGEST_SIZE]) +{ + struct sha1_ctx ctx; + + sha1_init(&ctx); + sha1_update(&ctx, data, len); + sha1_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(sha1); + +static void __hmac_sha1_preparekey(struct sha1_block_state *istate, + struct sha1_block_state *ostate, + const u8 *raw_key, size_t raw_key_len) +{ + union { + u8 b[SHA1_BLOCK_SIZE]; + unsigned long w[SHA1_BLOCK_SIZE / sizeof(unsigned long)]; + } derived_key = { 0 }; + + if (unlikely(raw_key_len > SHA1_BLOCK_SIZE)) + sha1(raw_key, raw_key_len, derived_key.b); + else + memcpy(derived_key.b, raw_key, raw_key_len); + + for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) + derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE); + *istate = sha1_iv; + sha1_blocks(istate, derived_key.b, 1); + + for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) + derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^ + HMAC_IPAD_VALUE); + *ostate = sha1_iv; + sha1_blocks(ostate, derived_key.b, 1); + + memzero_explicit(&derived_key, sizeof(derived_key)); +} + +void hmac_sha1_preparekey(struct hmac_sha1_key *key, + const u8 *raw_key, size_t raw_key_len) +{ + __hmac_sha1_preparekey(&key->istate, &key->ostate, + raw_key, raw_key_len); +} +EXPORT_SYMBOL_GPL(hmac_sha1_preparekey); + +void hmac_sha1_init(struct hmac_sha1_ctx *ctx, const struct hmac_sha1_key *key) +{ + ctx->sha_ctx.state = key->istate; + ctx->sha_ctx.bytecount = SHA1_BLOCK_SIZE; + ctx->ostate = key->ostate; +} +EXPORT_SYMBOL_GPL(hmac_sha1_init); + +void hmac_sha1_init_usingrawkey(struct hmac_sha1_ctx *ctx, + const u8 *raw_key, size_t raw_key_len) +{ + __hmac_sha1_preparekey(&ctx->sha_ctx.state, &ctx->ostate, + raw_key, raw_key_len); + ctx->sha_ctx.bytecount = SHA1_BLOCK_SIZE; +} +EXPORT_SYMBOL_GPL(hmac_sha1_init_usingrawkey); + +void hmac_sha1_final(struct hmac_sha1_ctx *ctx, u8 out[SHA1_DIGEST_SIZE]) +{ + /* Generate the padded input for the outer hash in ctx->sha_ctx.buf. */ + __sha1_final(&ctx->sha_ctx, ctx->sha_ctx.buf); + memset(&ctx->sha_ctx.buf[SHA1_DIGEST_SIZE], 0, + SHA1_BLOCK_SIZE - SHA1_DIGEST_SIZE); + ctx->sha_ctx.buf[SHA1_DIGEST_SIZE] = 0x80; + *(__be32 *)&ctx->sha_ctx.buf[SHA1_BLOCK_SIZE - 4] = + cpu_to_be32(8 * (SHA1_BLOCK_SIZE + SHA1_DIGEST_SIZE)); + + /* Compute the outer hash, which gives the HMAC value. */ + sha1_blocks(&ctx->ostate, ctx->sha_ctx.buf, 1); + for (size_t i = 0; i < SHA1_DIGEST_SIZE; i += 4) + put_unaligned_be32(ctx->ostate.h[i / 4], out + i); + + memzero_explicit(ctx, sizeof(*ctx)); +} +EXPORT_SYMBOL_GPL(hmac_sha1_final); + +void hmac_sha1(const struct hmac_sha1_key *key, + const u8 *data, size_t data_len, u8 out[SHA1_DIGEST_SIZE]) +{ + struct hmac_sha1_ctx ctx; + + hmac_sha1_init(&ctx, key); + hmac_sha1_update(&ctx, data, data_len); + hmac_sha1_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(hmac_sha1); + +void hmac_sha1_usingrawkey(const u8 *raw_key, size_t raw_key_len, + const u8 *data, size_t data_len, + u8 out[SHA1_DIGEST_SIZE]) +{ + struct hmac_sha1_ctx ctx; + + hmac_sha1_init_usingrawkey(&ctx, raw_key, raw_key_len); + hmac_sha1_update(&ctx, data, data_len); + hmac_sha1_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(hmac_sha1_usingrawkey); + +#if defined(sha1_mod_init_arch) || defined(CONFIG_CRYPTO_FIPS) +static int __init sha1_mod_init(void) +{ +#ifdef sha1_mod_init_arch + sha1_mod_init_arch(); +#endif + if (fips_enabled) { + /* + * FIPS cryptographic algorithm self-test. As per the FIPS + * Implementation Guidance, testing HMAC-SHA1 satisfies the test + * requirement for SHA-1 too. + */ + u8 mac[SHA1_DIGEST_SIZE]; + + hmac_sha1_usingrawkey(fips_test_key, sizeof(fips_test_key), + fips_test_data, sizeof(fips_test_data), + mac); + if (memcmp(fips_test_hmac_sha1_value, mac, sizeof(mac)) != 0) + panic("sha1: FIPS self-test failed\n"); + } + return 0; +} +subsys_initcall(sha1_mod_init); + +static void __exit sha1_mod_exit(void) +{ +} +module_exit(sha1_mod_exit); +#endif + +MODULE_DESCRIPTION("SHA-1 and HMAC-SHA1 library functions"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1