e04ca78ff8
fmt_asn1generic, see t10.c for example usage) add "generic" asn.1 dumper (in t10.c) fix some read off-by-one errors, minor cleanups add real OID support add bitstring support
28 lines
943 B
C
28 lines
943 B
C
#include "asn1.h"
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size_t scan_asn1BITSTRING(const char* src,const char* max,const char** s,size_t* l) {
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size_t tmp;
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unsigned long tag;
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enum asn1_tagclass tc;
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enum asn1_tagtype tt;
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if ((tmp=scan_asn1string(src,max,&tc,&tt,&tag,s,l)))
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if (tc==UNIVERSAL && tt==PRIMITIVE && tag==BIT_STRING) {
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unsigned char lastbyte;
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if (*l==0 || /* length must be at least 1 because for bit strings, the first octet contains the number of unused bits in the last octet */
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(unsigned char)(**s)>7) /* the number of unused bits in the last octet must not be negative and can be at most 7 */
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return 0;
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/* these are DER checks */
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/* can't have unused bits if the length is 0 */
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if (*l==1 && **s)
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return 0;
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/* now check if the unused bits are 0 */
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lastbyte=(*s)[*l+1];
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if (lastbyte & (0xff >> (8-**s)))
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return 0;
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*l=*l*8-(unsigned char)(**s);
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++*s;
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return tmp;
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}
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return 0;
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}
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