39 lines
858 B
C
39 lines
858 B
C
#include "os.h"
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#include <libsec.h>
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/* rfc5869 */
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void
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hkdf_x(salt, nsalt, info, ninfo, key, nkey, d, dlen, x, xlen)
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uint8_t *salt, *info, *key, *d;
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uint32_t nsalt, ninfo, nkey, dlen;
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DigestState* (*x)(uint8_t*, uint32_t, uint8_t*, uint32_t, uint8_t*, DigestState*);
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int xlen;
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{
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uint8_t prk[256], tmp[256], cnt;
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DigestState *ds;
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assert(xlen <= sizeof(tmp));
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jehanne_memset(tmp, 0, xlen);
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if(nsalt == 0){
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salt = tmp;
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nsalt = xlen;
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}
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/* note that salt and key are swapped in this case */
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(*x)(key, nkey, salt, nsalt, prk, nil);
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ds = nil;
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for(cnt=1;; cnt++) {
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if(ninfo > 0)
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ds = (*x)(info, ninfo, prk, xlen, nil, ds);
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(*x)(&cnt, 1, prk, xlen, tmp, ds);
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if(dlen <= xlen){
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jehanne_memmove(d, tmp, dlen);
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break;
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}
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jehanne_memmove(d, tmp, xlen);
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dlen -= xlen;
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d += xlen;
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ds = (*x)(tmp, xlen, prk, xlen, nil, nil);
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}
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}
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