ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/lib/crypto/poly1305-donna32.c b/lib/crypto/poly1305-donna32.c
new file mode 100644
index 000000000..b66131b3f
--- /dev/null
+++ b/lib/crypto/poly1305-donna32.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is based in part on Andrew Moon's poly1305-donna, which is in the
+ * public domain.
+ */
+
+#include <crypto/internal/poly1305.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/unaligned.h>
+
+void poly1305_core_setkey(struct poly1305_core_key *key,
+			  const u8 raw_key[POLY1305_BLOCK_SIZE])
+{
+	/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+	key->key.r[0] = (get_unaligned_le32(&raw_key[0])) & 0x3ffffff;
+	key->key.r[1] = (get_unaligned_le32(&raw_key[3]) >> 2) & 0x3ffff03;
+	key->key.r[2] = (get_unaligned_le32(&raw_key[6]) >> 4) & 0x3ffc0ff;
+	key->key.r[3] = (get_unaligned_le32(&raw_key[9]) >> 6) & 0x3f03fff;
+	key->key.r[4] = (get_unaligned_le32(&raw_key[12]) >> 8) & 0x00fffff;
+
+	/* s = 5*r */
+	key->precomputed_s.r[0] = key->key.r[1] * 5;
+	key->precomputed_s.r[1] = key->key.r[2] * 5;
+	key->precomputed_s.r[2] = key->key.r[3] * 5;
+	key->precomputed_s.r[3] = key->key.r[4] * 5;
+}
+EXPORT_SYMBOL(poly1305_core_setkey);
+
+void poly1305_core_blocks(struct poly1305_state *state,
+			  const struct poly1305_core_key *key, const void *src,
+			  unsigned int nblocks, u32 hibit)
+{
+	const u8 *input = src;
+	u32 r0, r1, r2, r3, r4;
+	u32 s1, s2, s3, s4;
+	u32 h0, h1, h2, h3, h4;
+	u64 d0, d1, d2, d3, d4;
+	u32 c;
+
+	if (!nblocks)
+		return;
+
+	hibit <<= 24;
+
+	r0 = key->key.r[0];
+	r1 = key->key.r[1];
+	r2 = key->key.r[2];
+	r3 = key->key.r[3];
+	r4 = key->key.r[4];
+
+	s1 = key->precomputed_s.r[0];
+	s2 = key->precomputed_s.r[1];
+	s3 = key->precomputed_s.r[2];
+	s4 = key->precomputed_s.r[3];
+
+	h0 = state->h[0];
+	h1 = state->h[1];
+	h2 = state->h[2];
+	h3 = state->h[3];
+	h4 = state->h[4];
+
+	do {
+		/* h += m[i] */
+		h0 += (get_unaligned_le32(&input[0])) & 0x3ffffff;
+		h1 += (get_unaligned_le32(&input[3]) >> 2) & 0x3ffffff;
+		h2 += (get_unaligned_le32(&input[6]) >> 4) & 0x3ffffff;
+		h3 += (get_unaligned_le32(&input[9]) >> 6) & 0x3ffffff;
+		h4 += (get_unaligned_le32(&input[12]) >> 8) | hibit;
+
+		/* h *= r */
+		d0 = ((u64)h0 * r0) + ((u64)h1 * s4) +
+		     ((u64)h2 * s3) + ((u64)h3 * s2) +
+		     ((u64)h4 * s1);
+		d1 = ((u64)h0 * r1) + ((u64)h1 * r0) +
+		     ((u64)h2 * s4) + ((u64)h3 * s3) +
+		     ((u64)h4 * s2);
+		d2 = ((u64)h0 * r2) + ((u64)h1 * r1) +
+		     ((u64)h2 * r0) + ((u64)h3 * s4) +
+		     ((u64)h4 * s3);
+		d3 = ((u64)h0 * r3) + ((u64)h1 * r2) +
+		     ((u64)h2 * r1) + ((u64)h3 * r0) +
+		     ((u64)h4 * s4);
+		d4 = ((u64)h0 * r4) + ((u64)h1 * r3) +
+		     ((u64)h2 * r2) + ((u64)h3 * r1) +
+		     ((u64)h4 * r0);
+
+		/* (partial) h %= p */
+		c = (u32)(d0 >> 26);
+		h0 = (u32)d0 & 0x3ffffff;
+		d1 += c;
+		c = (u32)(d1 >> 26);
+		h1 = (u32)d1 & 0x3ffffff;
+		d2 += c;
+		c = (u32)(d2 >> 26);
+		h2 = (u32)d2 & 0x3ffffff;
+		d3 += c;
+		c = (u32)(d3 >> 26);
+		h3 = (u32)d3 & 0x3ffffff;
+		d4 += c;
+		c = (u32)(d4 >> 26);
+		h4 = (u32)d4 & 0x3ffffff;
+		h0 += c * 5;
+		c = (h0 >> 26);
+		h0 = h0 & 0x3ffffff;
+		h1 += c;
+
+		input += POLY1305_BLOCK_SIZE;
+	} while (--nblocks);
+
+	state->h[0] = h0;
+	state->h[1] = h1;
+	state->h[2] = h2;
+	state->h[3] = h3;
+	state->h[4] = h4;
+}
+EXPORT_SYMBOL(poly1305_core_blocks);
+
+void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4],
+			void *dst)
+{
+	u8 *mac = dst;
+	u32 h0, h1, h2, h3, h4, c;
+	u32 g0, g1, g2, g3, g4;
+	u64 f;
+	u32 mask;
+
+	/* fully carry h */
+	h0 = state->h[0];
+	h1 = state->h[1];
+	h2 = state->h[2];
+	h3 = state->h[3];
+	h4 = state->h[4];
+
+	c = h1 >> 26;
+	h1 = h1 & 0x3ffffff;
+	h2 += c;
+	c = h2 >> 26;
+	h2 = h2 & 0x3ffffff;
+	h3 += c;
+	c = h3 >> 26;
+	h3 = h3 & 0x3ffffff;
+	h4 += c;
+	c = h4 >> 26;
+	h4 = h4 & 0x3ffffff;
+	h0 += c * 5;
+	c = h0 >> 26;
+	h0 = h0 & 0x3ffffff;
+	h1 += c;
+
+	/* compute h + -p */
+	g0 = h0 + 5;
+	c = g0 >> 26;
+	g0 &= 0x3ffffff;
+	g1 = h1 + c;
+	c = g1 >> 26;
+	g1 &= 0x3ffffff;
+	g2 = h2 + c;
+	c = g2 >> 26;
+	g2 &= 0x3ffffff;
+	g3 = h3 + c;
+	c = g3 >> 26;
+	g3 &= 0x3ffffff;
+	g4 = h4 + c - (1UL << 26);
+
+	/* select h if h < p, or h + -p if h >= p */
+	mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;
+	g0 &= mask;
+	g1 &= mask;
+	g2 &= mask;
+	g3 &= mask;
+	g4 &= mask;
+	mask = ~mask;
+
+	h0 = (h0 & mask) | g0;
+	h1 = (h1 & mask) | g1;
+	h2 = (h2 & mask) | g2;
+	h3 = (h3 & mask) | g3;
+	h4 = (h4 & mask) | g4;
+
+	/* h = h % (2^128) */
+	h0 = ((h0) | (h1 << 26)) & 0xffffffff;
+	h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;
+	h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
+	h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;
+
+	if (likely(nonce)) {
+		/* mac = (h + nonce) % (2^128) */
+		f = (u64)h0 + nonce[0];
+		h0 = (u32)f;
+		f = (u64)h1 + nonce[1] + (f >> 32);
+		h1 = (u32)f;
+		f = (u64)h2 + nonce[2] + (f >> 32);
+		h2 = (u32)f;
+		f = (u64)h3 + nonce[3] + (f >> 32);
+		h3 = (u32)f;
+	}
+
+	put_unaligned_le32(h0, &mac[0]);
+	put_unaligned_le32(h1, &mac[4]);
+	put_unaligned_le32(h2, &mac[8]);
+	put_unaligned_le32(h3, &mac[12]);
+}
+EXPORT_SYMBOL(poly1305_core_emit);