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der flexi decoder: remove duplicate code

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This commit is contained in:
Steffen Jaeckel 2014-10-06 18:28:47 +02:00
parent 3d1231ab15
commit f0a1235614
1 changed files with 15 additions and 32 deletions
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47
src/pk/asn1/der/sequence/der_decode_sequence_flexi.c
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@ -17,24 +17,24 @@
#ifdef LTC_DER #ifdef LTC_DER
static unsigned long fetch_length(const unsigned char *in, unsigned long inlen) static unsigned long fetch_length(const unsigned char *in, unsigned long inlen, unsigned long *data_offset)
{ {
unsigned long x, y, z; unsigned long x, z;
y = 0; *data_offset = 0;
/* skip type and read len */ /* skip type and read len */
if (inlen < 2) { if (inlen < 2) {
return 0xFFFFFFFF; return 0xFFFFFFFF;
} }
++in; ++y; ++in; ++(*data_offset);
/* read len */ /* read len */
x = *in++; ++y; x = *in++; ++(*data_offset);
/* <128 means literal */ /* <128 means literal */
if (x < 128) { if (x < 128) {
return x+y; return x+*data_offset;
} }
x &= 0x7F; /* the lower 7 bits are the length of the length */ x &= 0x7F; /* the lower 7 bits are the length of the length */
inlen -= 2; inlen -= 2;
@ -44,13 +44,13 @@ static unsigned long fetch_length(const unsigned char *in, unsigned long inlen)
return 0xFFFFFFFF; return 0xFFFFFFFF;
} }
y += x; *data_offset += x;
z = 0; z = 0;
while (x--) { while (x--) {
z = (z<<8) | ((unsigned long)*in); z = (z<<8) | ((unsigned long)*in);
++in; ++in;
} }
return z+y; return z+*data_offset;
} }
/** /**
@ -63,7 +63,7 @@ static unsigned long fetch_length(const unsigned char *in, unsigned long inlen)
int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc_asn1_list **out) int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc_asn1_list **out)
{ {
ltc_asn1_list *l; ltc_asn1_list *l;
unsigned long err, type, len, totlen, x, y; unsigned long err, type, len, totlen, data_offset;
void *realloc_tmp; void *realloc_tmp;
LTC_ARGCHK(in != NULL); LTC_ARGCHK(in != NULL);
@ -79,7 +79,7 @@ int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc
type = *in; type = *in;
/* fetch length */ /* fetch length */
len = fetch_length(in, *inlen); len = fetch_length(in, *inlen, &data_offset);
if (len > *inlen) { if (len > *inlen) {
err = CRYPT_INVALID_PACKET; err = CRYPT_INVALID_PACKET;
goto error; goto error;
@ -342,35 +342,18 @@ int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc
l->type = LTC_ASN1_SET; l->type = LTC_ASN1_SET;
} }
/* we have to decode the SEQUENCE header and get it's length */ /* jump to the start of the data */
in += data_offset;
/* move past type */ *inlen -= data_offset;
++in; --(*inlen); len = len - data_offset;
/* read length byte */
x = *in++; --(*inlen);
/* smallest SEQUENCE/SET header */
y = 2;
/* now if it's > 127 the next bytes are the length of the length */
if (x > 128) {
x &= 0x7F;
in += x;
*inlen -= x;
/* update sequence header len */
y += x;
}
/* Sequence elements go as child */ /* Sequence elements go as child */
len = len - y;
if ((err = der_decode_sequence_flexi(in, &len, &(l->child))) != CRYPT_OK) { if ((err = der_decode_sequence_flexi(in, &len, &(l->child))) != CRYPT_OK) {
goto error; goto error;
} }
/* len update */ /* len update */
totlen += y; totlen += data_offset;
/* link them up y0 */ /* link them up y0 */
l->child->parent = l; l->child->parent = l;