67 lines
2.0 KiB
C
67 lines
2.0 KiB
C
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/cryptohash.h>
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/* F, G and H are basic MD4 functions: selection, majority, parity */
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#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
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#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
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#define H(x, y, z) ((x) ^ (y) ^ (z))
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/*
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* The generic round function. The application is so specific that
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* we don't bother protecting all the arguments with parens, as is generally
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* good macro practice, in favor of extra legibility.
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* Rotation is separate from addition to prevent recomputation
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*/
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#define ROUND(f, a, b, c, d, x, s) \
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(a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s)))
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#define K1 0
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#define K2 013240474631UL
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#define K3 015666365641UL
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/*
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* Basic cut-down MD4 transform. Returns only 32 bits of result.
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*/
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__u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
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{
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__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
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/* Round 1 */
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ROUND(F, a, b, c, d, in[0] + K1, 3);
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ROUND(F, d, a, b, c, in[1] + K1, 7);
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ROUND(F, c, d, a, b, in[2] + K1, 11);
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ROUND(F, b, c, d, a, in[3] + K1, 19);
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ROUND(F, a, b, c, d, in[4] + K1, 3);
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ROUND(F, d, a, b, c, in[5] + K1, 7);
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ROUND(F, c, d, a, b, in[6] + K1, 11);
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ROUND(F, b, c, d, a, in[7] + K1, 19);
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/* Round 2 */
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ROUND(G, a, b, c, d, in[1] + K2, 3);
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ROUND(G, d, a, b, c, in[3] + K2, 5);
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ROUND(G, c, d, a, b, in[5] + K2, 9);
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ROUND(G, b, c, d, a, in[7] + K2, 13);
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ROUND(G, a, b, c, d, in[0] + K2, 3);
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ROUND(G, d, a, b, c, in[2] + K2, 5);
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ROUND(G, c, d, a, b, in[4] + K2, 9);
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ROUND(G, b, c, d, a, in[6] + K2, 13);
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/* Round 3 */
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ROUND(H, a, b, c, d, in[3] + K3, 3);
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ROUND(H, d, a, b, c, in[7] + K3, 9);
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ROUND(H, c, d, a, b, in[2] + K3, 11);
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ROUND(H, b, c, d, a, in[6] + K3, 15);
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ROUND(H, a, b, c, d, in[1] + K3, 3);
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ROUND(H, d, a, b, c, in[5] + K3, 9);
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ROUND(H, c, d, a, b, in[0] + K3, 11);
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ROUND(H, b, c, d, a, in[4] + K3, 15);
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buf[0] += a;
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buf[1] += b;
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buf[2] += c;
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buf[3] += d;
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return buf[1]; /* "most hashed" word */
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}
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EXPORT_SYMBOL(half_md4_transform);
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