Merge remote-tracking branch 'github/master'

[stg.git] / libs / smux / per_support.c

diff --git a/libs/smux/per_support.c b/libs/smux/per_support.c
index c83441931caf1fcc3a79c0062014833db3d141b5..8f4d46040bbfffb22a10a144e29263b02fa85741 100644 (file)
--- a/libs/smux/per_support.c
+++ b/libs/smux/per_support.c
@@ -1,5 +1,5 @@
 /*
 /*

- * 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>
  * Redistribution and modifications are permitted subject to BSD license.
  */
 #include <asn_system.h>


@@ -7,126 +7,64 @@
 #include <per_support.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
  */
 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);

 }
 
 /*
 }
 
 /*


@@ -156,8 +94,8 @@ uper_get_nsnnwn(asn_per_data_t *pd) {
 }
 
 /*
 }
 
 /*

- * 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) {
  */
 int
 uper_put_nsnnwn(asn_per_outp_t *po, int n) {


@@ -182,137 +120,176 @@ 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;
 }
 
 
        return 0;
 }
 
 

-/*
- * Output a large number of bits.
- */
+/* X.691-2008/11, #11.5.6 -> #11.3 */

 int
 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
  * 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;
+}