/*
- * Copyright (c) 2005, 2006 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
* Redistribution and modifications are permitted subject to BSD license.
*/
#include <asn_system.h>
#include <per_support.h>
/*
- * Extract a small number of bits (<= 31) from the specified PER data pointer.
+ * X.691-201508 #10.9 General rules for encoding a length determinant.
+ * Get the optionally constrained length "n" from the stream.
*/
-int32_t
-per_get_few_bits(asn_per_data_t *pd, int nbits) {
- size_t off; /* Next after last bit offset */
- uint32_t accum;
- const uint8_t *buf;
-
- if(nbits < 0 || pd->nboff + nbits > pd->nbits)
- return -1;
+ssize_t
+uper_get_length(asn_per_data_t *pd, int ebits, size_t lower_bound,
+ int *repeat) {
+ ssize_t value;
- ASN_DEBUG("[PER get %d bits from %p+%d bits]",
- nbits, pd->buffer, pd->nboff);
+ *repeat = 0;
- /*
- * Normalize position indicator.
- */
- if(pd->nboff >= 8) {
- pd->buffer += (pd->nboff >> 3);
- pd->nbits -= (pd->nboff & ~0x07);
- pd->nboff &= 0x07;
- }
- off = (pd->nboff += nbits);
- buf = pd->buffer;
-
- /*
- * Extract specified number of bits.
- */
- if(off <= 8)
- accum = nbits ? (buf[0]) >> (8 - off) : 0;
- else if(off <= 16)
- accum = ((buf[0] << 8) + buf[1]) >> (16 - off);
- else if(off <= 24)
- accum = ((buf[0] << 16) + (buf[1] << 8) + buf[2]) >> (24 - off);
- else if(off <= 31)
- accum = ((buf[0] << 24) + (buf[1] << 16)
- + (buf[2] << 8) + (buf[3])) >> (32 - off);
- else if(nbits <= 31) {
- asn_per_data_t tpd = *pd;
- /* Here are we with our 31-bits limit plus 1..7 bits offset. */
- tpd.nboff -= nbits;
- accum = per_get_few_bits(&tpd, nbits - 24) << 24;
- accum |= per_get_few_bits(&tpd, 24);
- } else {
- pd->nboff -= nbits; /* Oops, revert back */
- return -1;
- }
+ /* #11.9.4.1 Encoding if constrained (according to effective bits) */
+ if(ebits >= 0 && ebits <= 16) {
+ value = per_get_few_bits(pd, ebits);
+ if(value >= 0) value += lower_bound;
+ return value;
+ }
- return (accum & (((uint32_t)1 << nbits) - 1));
-}
-
-/*
- * Extract a large number of bits from the specified PER data pointer.
- */
-int
-per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int alright, int nbits) {
- int32_t value;
-
- if(alright && (nbits & 7)) {
- /* Perform right alignment of a first few bits */
- value = per_get_few_bits(pd, nbits & 0x07);
- if(value < 0) return -1;
- *dst++ = value; /* value is already right-aligned */
- nbits &= ~7;
- }
-
- while(nbits) {
- if(nbits >= 24) {
- value = per_get_few_bits(pd, 24);
- if(value < 0) return -1;
- *(dst++) = value >> 16;
- *(dst++) = value >> 8;
- *(dst++) = value;
- nbits -= 24;
- } else {
- value = per_get_few_bits(pd, nbits);
- if(value < 0) return -1;
- if(nbits & 7) { /* implies left alignment */
- value <<= 8 - (nbits & 7),
- nbits += 8 - (nbits & 7);
- if(nbits > 24)
- *dst++ = value >> 24;
- }
- if(nbits > 16)
- *dst++ = value >> 16;
- if(nbits > 8)
- *dst++ = value >> 8;
- *dst++ = value;
- break;
- }
- }
-
- return 0;
+ value = per_get_few_bits(pd, 8);
+ if((value & 0x80) == 0) { /* #11.9.3.6 */
+ return (value & 0x7F);
+ } else if((value & 0x40) == 0) { /* #11.9.3.7 */
+ /* bit 8 ... set to 1 and bit 7 ... set to zero */
+ value = ((value & 0x3f) << 8) | per_get_few_bits(pd, 8);
+ return value; /* potential -1 from per_get_few_bits passes through. */
+ } else if(value < 0) {
+ ASN_DEBUG("END of stream reached for PER");
+ return -1;
+ }
+ value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */
+ if(value < 1 || value > 4) {
+ return -1; /* Prohibited by #11.9.3.8 */
+ }
+ *repeat = 1;
+ return (16384 * value);
}
/*
- * Get the length "n" from the stream.
+ * Get the normally small length "n".
+ * This procedure used to decode length of extensions bit-maps
+ * for SET and SEQUENCE types.
*/
ssize_t
-uper_get_length(asn_per_data_t *pd, int ebits, int *repeat) {
- ssize_t value;
+uper_get_nslength(asn_per_data_t *pd) {
+ ssize_t length;
- *repeat = 0;
+ ASN_DEBUG("Getting normally small length");
- if(ebits >= 0) return per_get_few_bits(pd, ebits);
-
- value = per_get_few_bits(pd, 8);
- if(value < 0) return -1;
- if((value & 128) == 0) /* #10.9.3.6 */
- return (value & 0x7F);
- if((value & 64) == 0) { /* #10.9.3.7 */
- value = ((value & 63) << 8) | per_get_few_bits(pd, 8);
- if(value < 0) return -1;
- return value;
+ if(per_get_few_bits(pd, 1) == 0) {
+ length = per_get_few_bits(pd, 6) + 1;
+ if(length <= 0) return -1;
+ ASN_DEBUG("l=%d", (int)length);
+ return length;
+ } else {
+ int repeat;
+ length = uper_get_length(pd, -1, 0, &repeat);
+ if(length >= 0 && !repeat) return length;
+ return -1; /* Error, or do not support >16K extensions */
}
- value &= 63; /* this is "m" from X.691, #10.9.3.8 */
- if(value < 1 || value > 4)
- return -1;
- *repeat = 1;
- return (16384 * value);
}
/*
}
/*
- * Put the normally small non-negative whole number.
- * X.691, #10.6
+ * X.691-11/2008, #11.6
+ * Encoding of a normally small non-negative whole number
*/
int
uper_put_nsnnwn(asn_per_outp_t *po, int n) {
}
-/*
- * Put a small number of bits (<= 31).
- */
-int
-per_put_few_bits(asn_per_outp_t *po, uint32_t bits, int obits) {
- size_t off; /* Next after last bit offset */
- size_t omsk; /* Existing last byte meaningful bits mask */
- uint8_t *buf;
-
- if(obits <= 0 || obits >= 32) return obits ? -1 : 0;
-
- ASN_DEBUG("[PER put %d bits to %p+%d bits]",
- obits, po->buffer, po->nboff);
-
- /*
- * Normalize position indicator.
- */
- if(po->nboff >= 8) {
- po->buffer += (po->nboff >> 3);
- po->nbits -= (po->nboff & ~0x07);
- po->nboff &= 0x07;
- }
+/* X.691-2008/11, #11.5.6 -> #11.3 */
+int uper_get_constrained_whole_number(asn_per_data_t *pd, unsigned long *out_value, int nbits) {
+ unsigned long lhalf; /* Lower half of the number*/
+ long half;
- /*
- * Flush whole-bytes output, if necessary.
- */
- if(po->nboff + obits > po->nbits) {
- int complete_bytes = (po->buffer - po->tmpspace);
- if(po->outper(po->buffer, complete_bytes, po->op_key) < 0)
- return -1;
- if(po->nboff)
- po->tmpspace[0] = po->buffer[0];
- po->buffer = po->tmpspace;
- po->nbits = 8 * sizeof(po->tmpspace);
- po->flushed_bytes += complete_bytes;
+ if(nbits <= 31) {
+ half = per_get_few_bits(pd, nbits);
+ if(half < 0) return -1;
+ *out_value = half;
+ return 0;
}
- /*
- * Now, due to sizeof(tmpspace), we are guaranteed large enough space.
- */
- buf = po->buffer;
- omsk = ~((1 << (8 - po->nboff)) - 1);
- off = (po->nboff += obits);
-
- /* Clear data of debris before meaningful bits */
- bits &= (((uint32_t)1 << obits) - 1);
-
- ASN_DEBUG("[PER out %d %u/%x (t=%d,o=%d) %x&%x=%x]", obits, bits, bits,
- po->nboff - obits, off, buf[0], omsk&0xff, buf[0] & omsk);
-
- if(off <= 8) /* Completely within 1 byte */
- bits <<= (8 - off),
- buf[0] = (buf[0] & omsk) | bits;
- else if(off <= 16)
- bits <<= (16 - off),
- buf[0] = (buf[0] & omsk) | (bits >> 8),
- buf[1] = bits;
- else if(off <= 24)
- bits <<= (24 - off),
- buf[0] = (buf[0] & omsk) | (bits >> 16),
- buf[1] = bits >> 8,
- buf[2] = bits;
- else if(off <= 31)
- bits <<= (32 - off),
- buf[0] = (buf[0] & omsk) | (bits >> 24),
- buf[1] = bits >> 16,
- buf[2] = bits >> 8,
- buf[3] = bits;
- else {
- ASN_DEBUG("->[PER out split %d]", obits);
- per_put_few_bits(po, bits >> 8, 24);
- per_put_few_bits(po, bits, obits - 24);
- ASN_DEBUG("<-[PER out split %d]", obits);
- }
+ if((size_t)nbits > 8 * sizeof(*out_value))
+ return -1; /* RANGE */
- ASN_DEBUG("[PER out %u/%x => %02x buf+%d]",
- bits, bits, buf[0], po->buffer - po->tmpspace);
+ half = per_get_few_bits(pd, 31);
+ if(half < 0) return -1;
+ if(uper_get_constrained_whole_number(pd, &lhalf, nbits - 31))
+ return -1;
+
+ *out_value = ((unsigned long)half << (nbits - 31)) | lhalf;
return 0;
}
-/*
- * Output a large number of bits.
- */
+/* X.691-2008/11, #11.5.6 -> #11.3 */
int
-per_put_many_bits(asn_per_outp_t *po, const uint8_t *src, int nbits) {
-
- while(nbits) {
- uint32_t value;
-
- if(nbits >= 24) {
- value = (src[0] << 16) | (src[1] << 8) | src[2];
- src += 3;
- nbits -= 24;
- if(per_put_few_bits(po, value, 24))
- return -1;
- } else {
- value = src[0];
- if(nbits > 8)
- value = (value << 8) | src[1];
- if(nbits > 16)
- value = (value << 8) | src[2];
- if(nbits & 0x07)
- value >>= (8 - (nbits & 0x07));
- if(per_put_few_bits(po, value, nbits))
- return -1;
- break;
- }
- }
-
- return 0;
+uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v,
+ int nbits) {
+ if(nbits <= 31) {
+ return per_put_few_bits(po, v, nbits);
+ } else {
+ /* Put higher portion first, followed by lower 31-bit */
+ if(uper_put_constrained_whole_number_u(po, v >> 31, nbits - 31))
+ return -1;
+ return per_put_few_bits(po, v, 31);
+ }
}
/*
+ * X.691 (08/2015) #11.9 "General rules for encoding a length determinant"
* Put the length "n" (or part of it) into the stream.
*/
ssize_t
-uper_put_length(asn_per_outp_t *po, size_t length) {
+uper_put_length(asn_per_outp_t *po, size_t length, int *need_eom) {
+ int dummy = 0;
+ if(!need_eom) need_eom = &dummy;
+
+ if(length <= 127) { /* #11.9.3.6 */
+ *need_eom = 0;
+ return per_put_few_bits(po, length, 8)
+ ? -1 : (ssize_t)length;
+ } else if(length < 16384) { /* #10.9.3.7 */
+ *need_eom = 0;
+ return per_put_few_bits(po, length|0x8000, 16)
+ ? -1 : (ssize_t)length;
+ }
+
+ *need_eom = 0 == (length & 16383);
+ length >>= 14;
+ if(length > 4) {
+ *need_eom = 0;
+ length = 4;
+ }
+
+ return per_put_few_bits(po, 0xC0 | length, 8)
+ ? -1 : (ssize_t)(length << 14);
+
+}
- if(length <= 127) /* #10.9.3.6 */
- return per_put_few_bits(po, length, 8)
- ? -1 : (ssize_t)length;
- else if(length < 16384) /* #10.9.3.7 */
- return per_put_few_bits(po, length|0x8000, 16)
- ? -1 : (ssize_t)length;
- length >>= 14;
- if(length > 4) length = 4;
+/*
+ * Put the normally small length "n" into the stream.
+ * This procedure used to encode length of extensions bit-maps
+ * for SET and SEQUENCE types.
+ */
+int
+uper_put_nslength(asn_per_outp_t *po, size_t length) {
+ if(length <= 64) {
+ /* #11.9.3.4 */
+ if(length == 0) return -1;
+ return per_put_few_bits(po, length - 1, 7) ? -1 : 0;
+ } else {
+ int need_eom = 0;
+ if(uper_put_length(po, length, &need_eom) != (ssize_t)length
+ || need_eom) {
+ /* This might happen in case of >16K extensions */
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int
+per__long_range(long lb, long ub, unsigned long *range_r) {
+ unsigned long bounds_range;
+ if((ub < 0) == (lb < 0)) {
+ bounds_range = ub - lb;
+ } else if(lb < 0) {
+ assert(ub >= 0);
+ bounds_range = 1 + ((unsigned long)ub + (unsigned long)-(lb + 1));
+ } else {
+ assert(!"Unreachable");
+ return -1;
+ }
+ *range_r = bounds_range;
+ return 0;
+}
- return per_put_few_bits(po, 0xC0 | length, 8)
- ? -1 : (ssize_t)(length << 14);
+int
+per_long_range_rebase(long v, long lb, long ub, unsigned long *output) {
+ unsigned long range;
+
+ assert(lb <= ub);
+
+ if(v < lb || v > ub || per__long_range(lb, ub, &range) < 0) {
+ /* Range error. */
+ return -1;
+ }
+
+ /*
+ * Fundamentally what we're doing is returning (v-lb).
+ * However, this triggers undefined behavior when the word width
+ * of signed (v) is the same as the size of unsigned (*output).
+ * In practice, it triggers the UndefinedSanitizer. Therefore we shall
+ * compute the ranges accurately to avoid C's undefined behavior.
+ */
+ if((v < 0) == (lb < 0)) {
+ *output = v-lb;
+ return 0;
+ } else if(v < 0) {
+ unsigned long rebased = 1 + (unsigned long)-(v+1) + (unsigned long)lb;
+ assert(rebased <= range); /* By construction */
+ *output = rebased;
+ return 0;
+ } else if(lb < 0) {
+ unsigned long rebased = 1 + (unsigned long)-(lb+1) + (unsigned long)v;
+ assert(rebased <= range); /* By construction */
+ *output = rebased;
+ return 0;
+ } else {
+ assert(!"Unreachable");
+ return -1;
+ }
}
+int
+per_long_range_unrebase(unsigned long inp, long lb, long ub, long *outp) {
+ unsigned long range;
+
+ if(per__long_range(lb, ub, &range) != 0) {
+ return -1;
+ }
+
+ if(inp > range) {
+ /*
+ * We can encode something in the given number of bits that technically
+ * exceeds the range. This is an avenue for security errors,
+ * so we don't allow that.
+ */
+ return -1;
+ }
+
+ if(inp <= LONG_MAX) {
+ *outp = (long)inp + lb;
+ } else {
+ *outp = (lb + LONG_MAX + 1) + (long)((inp - LONG_MAX) - 1);
+ }
+
+ return 0;
+}
git.stg.codes / stg.git / blobdiff