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https://github.com/fluencelabs/redis
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Detect corrupted sparse HLLs in hllSparseSum().
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@ -869,7 +869,7 @@ promote: /* Promote to dense representation. */
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* PE is an array with a pre-computer table of values 2^-reg indexed by reg.
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* As a side effect the integer pointed by 'ezp' is set to the number
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* of zero registers. */
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double hllSparseSum(uint8_t *sparse, int sparselen, double *PE, int *ezp) {
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double hllSparseSum(uint8_t *sparse, int sparselen, double *PE, int *ezp, int *invalid) {
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double E = 0;
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int ez = 0, idx = 0, runlen, regval;
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uint8_t *end = sparse+sparselen, *p = sparse;
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@ -895,7 +895,7 @@ double hllSparseSum(uint8_t *sparse, int sparselen, double *PE, int *ezp) {
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p++;
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}
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}
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redisAssert(idx == HLL_REGISTERS);
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if (idx != HLL_REGISTERS && invalid) *invalid = 1;
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*ezp = ez;
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return E;
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}
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@ -908,13 +908,14 @@ double hllSparseSum(uint8_t *sparse, int sparselen, double *PE, int *ezp) {
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/* Return the approximated cardinality of the set based on the armonic
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* mean of the registers values. 'hdr' points to the start of the SDS
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* representing the String object holding the HLL representation. */
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uint64_t hllCount(struct hllhdr *hdr) {
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* representing the String object holding the HLL representation.
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*
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* If the sparse representation of the HLL object is not valid, the integer
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* pointed by 'invalid' is set to non-zero, otherwise it is left untouched. */
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uint64_t hllCount(struct hllhdr *hdr, int *invalid) {
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double m = HLL_REGISTERS;
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double alpha = 0.7213/(1+1.079/m);
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double E;
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int ez; /* Number of registers equal to 0. */
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int j;
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double E, alpha = 0.7213/(1+1.079/m);
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int j, ez; /* Number of registers equal to 0. */
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/* We precompute 2^(-reg[j]) in a small table in order to
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* speedup the computation of SUM(2^-register[0..i]). */
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@ -933,7 +934,8 @@ uint64_t hllCount(struct hllhdr *hdr) {
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if (hdr->encoding == HLL_DENSE) {
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E = hllDenseSum(hdr->registers,PE,&ez);
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} else {
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E = hllSparseSum(hdr->registers,sdslen((sds)hdr)-HLL_HDR_SIZE,PE,&ez);
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E = hllSparseSum(hdr->registers,
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sdslen((sds)hdr)-HLL_HDR_SIZE,PE,&ez,invalid);
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}
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/* Muliply the inverse of E for alpha_m * m^2 to have the raw estimate. */
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@ -1111,8 +1113,13 @@ void pfcountCommand(redisClient *c) {
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card |= (uint64_t)hdr->card[6] << 48;
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card |= (uint64_t)hdr->card[7] << 56;
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} else {
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int invalid = 0;
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/* Recompute it and update the cached value. */
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card = hllCount(hdr);
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card = hllCount(hdr,&invalid);
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if (invalid) {
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addReplyError(c,"Invalid HLL object");
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return;
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}
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hdr->card[0] = card & 0xff;
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hdr->card[1] = (card >> 8) & 0xff;
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hdr->card[2] = (card >> 16) & 0xff;
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@ -1245,7 +1252,7 @@ void pfselftestCommand(redisClient *c) {
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ele = j ^ seed;
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hllDenseAdd(hdr->registers,(unsigned char*)&ele,sizeof(ele));
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if (j == checkpoint) {
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int64_t abserr = checkpoint- (int64_t)hllCount(hdr);
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int64_t abserr = checkpoint - (int64_t)hllCount(hdr,NULL);
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if (abserr < 0) abserr = -abserr;
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if (abserr > (uint64_t)(relerr*4*checkpoint)) {
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addReplyErrorFormat(c,
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