mirror/openldap
2
0
Fork 0
mirror of https://git.openldap.org/openldap/openldap.git synced 2024-12-21 03:10:25 +08:00
Code Issues Packages Projects Releases Wiki Activity

Integer indexing - cleanup, signedness, redefine signmask => RIP overflow test

Browse Source
This commit is contained in:
Hallvard Furuseth 2007-12-03 09:54:01 +00:00
parent ccfe26fca9
commit 8667a535dc
1 changed files with 18 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
servers/slapd/schema_init.c
View File

@ -2114,7 +2114,7 @@ integerMatch(
return LDAP_SUCCESS;
}
/* 10**INDEX_INTLEN_CHOP < 256**INDEX_INTLEN_CHOPBYTES */
/* 10**Chop < 256**Chopbytes and Chop > Chopbytes<<1 (for sign bit and itmp) */
#define INDEX_INTLEN_CHOP 7
#define INDEX_INTLEN_CHOPBYTES 3
@ -2123,19 +2123,18 @@ integerVal2Key(
struct berval *in,
struct berval *key,
struct berval *tmp,
void *ctx
)
void *ctx )
{
/* index format:
* only if too large: one's complement <sign*length of chopped bytes>,
* only if too large: one's complement <sign*exponent (chopped bytes)>,
* two's complement value (sign-extended or chopped as needed),
* with 1st byte of the above adjusted as follows:
* inverse sign in the top <number of length-bytes + 1> bits,
* then the sign bit as delimiter.
* however the top <number of exponent-bytes + 1> bits of first byte
* above is the inverse sign. The next bit is the sign as delimiter.
*/
ber_slen_t k = index_intlen_strlen, chop = 0;
unsigned char neg = 0xff, signmask = 0x80;
unsigned char lenbuf[sizeof(k) + 2], *lenp;
ber_slen_t k = index_intlen_strlen;
ber_len_t chop = 0;
unsigned signmask = ~0x7fU;
unsigned char lenbuf[sizeof(k) + 2], *lenp, neg = 0xff;
struct berval val = *in, itmp = *tmp;
if ( val.bv_val[0] != '-' ) {
@ -2144,12 +2143,8 @@ integerVal2Key(
}
/* Chop least significant digits, increase length instead */
if ( val.bv_len > k ) {
if ( val.bv_len > (ber_len_t) k ) {
chop = (val.bv_len-k+2)/INDEX_INTLEN_CHOP; /* 2 fewer digits */
if ( chop > 0x7fffffff / INDEX_INTLEN_CHOPBYTES ) {
memset( key->bv_val, neg ^ 0xff, index_intlen );
return 0;
}
val.bv_len -= chop * INDEX_INTLEN_CHOP; /* #digits chopped */
chop *= INDEX_INTLEN_CHOPBYTES; /* #bytes added */
}
@ -2164,27 +2159,27 @@ integerVal2Key(
itmp.bv_len--;
}
k = (ber_slen_t) index_intlen - ((ber_slen_t) itmp.bv_len + chop);
k = (ber_slen_t) index_intlen - (ber_slen_t) (itmp.bv_len + chop);
if ( k > 0 ) {
assert( chop == 0 );
memset( key->bv_val, neg, k ); /* sign-extend */
} else if ( k != 0 || ((itmp.bv_val[0] ^ neg) & 0xc0) ) {
lenp = lenbuf + sizeof(lenbuf);
k = -k;
chop = - (ber_len_t) k;
do {
*--lenp = k ^ neg;
*--lenp = ((unsigned char) chop & 0xff) ^ neg;
signmask >>= 1;
} while ( (k >>= 8) != 0 || (signmask >> 1) <= (*lenp ^ neg) );
/* With n bytes used in lenbuf, the top n+1 bits of signmask
* are 1, and the top n+2 bits of *lenp are the sign bit. */
} while ( (chop >>= 8) != 0 || (signmask >> 1) & (*lenp ^ neg) );
/* With n bytes in lenbuf, the top n+1 bits of (signmask&0xff)
* are 1, and the top n+2 bits of lenp[] are the sign bit. */
k = (lenbuf + sizeof(lenbuf)) - lenp;
if ( k > index_intlen )
if ( k > (ber_slen_t) index_intlen )
k = index_intlen;
memcpy( key->bv_val, lenp, k );
itmp.bv_len = index_intlen - k;
}
memcpy( key->bv_val + k, itmp.bv_val, itmp.bv_len );
key->bv_val[0] ^= (unsigned char) -signmask & 0xff; /* invert sign */
key->bv_val[0] ^= (unsigned char) signmask & 0xff; /* invert sign */
return 0;
}