X-Git-Url: https://git.stg.codes/stg.git/blobdiff_plain/8c6fa3fbaccc22127280bf77a48fab5a3ee0716e..46b0747592074017ff0ea4b33d4a7194235886e5:/stglibs/smux.lib/ber_decoder.c diff --git a/stglibs/smux.lib/ber_decoder.c b/stglibs/smux.lib/ber_decoder.c deleted file mode 100644 index 601f66c0..00000000 --- a/stglibs/smux.lib/ber_decoder.c +++ /dev/null @@ -1,283 +0,0 @@ -/*- - * Copyright (c) 2003, 2004 Lev Walkin . All rights reserved. - * Redistribution and modifications are permitted subject to BSD license. - */ -#include - -#undef ADVANCE -#define ADVANCE(num_bytes) do { \ - size_t num = num_bytes; \ - ptr = ((const char *)ptr) + num; \ - size -= num; \ - consumed_myself += num; \ - } while(0) -#undef RETURN -#define RETURN(_code) do { \ - asn_dec_rval_t rval; \ - rval.code = _code; \ - if(opt_ctx) opt_ctx->step = step; /* Save context */ \ - if(_code == RC_OK || opt_ctx) \ - rval.consumed = consumed_myself; \ - else \ - rval.consumed = 0; /* Context-free */ \ - return rval; \ - } while(0) - -/* - * The BER decoder of any type. - */ -asn_dec_rval_t -ber_decode(asn_codec_ctx_t *opt_codec_ctx, - asn_TYPE_descriptor_t *type_descriptor, - void **struct_ptr, const void *ptr, size_t size) { - asn_codec_ctx_t s_codec_ctx; - - /* - * Stack checker requires that the codec context - * must be allocated on the stack. - */ - if(opt_codec_ctx) { - if(opt_codec_ctx->max_stack_size) { - s_codec_ctx = *opt_codec_ctx; - opt_codec_ctx = &s_codec_ctx; - } - } else { - /* If context is not given, be security-conscious anyway */ - memset(&s_codec_ctx, 0, sizeof(s_codec_ctx)); - s_codec_ctx.max_stack_size = _ASN_DEFAULT_STACK_MAX; - opt_codec_ctx = &s_codec_ctx; - } - - /* - * Invoke type-specific decoder. - */ - return type_descriptor->ber_decoder(opt_codec_ctx, type_descriptor, - struct_ptr, /* Pointer to the destination structure */ - ptr, size, /* Buffer and its size */ - 0 /* Default tag mode is 0 */ - ); -} - -/* - * Check the set of >> tags matches the definition. - */ -asn_dec_rval_t -ber_check_tags(asn_codec_ctx_t *opt_codec_ctx, - asn_TYPE_descriptor_t *td, asn_struct_ctx_t *opt_ctx, - const void *ptr, size_t size, int tag_mode, int last_tag_form, - ber_tlv_len_t *last_length, int *opt_tlv_form) { - ssize_t consumed_myself = 0; - ssize_t tag_len; - ssize_t len_len; - ber_tlv_tag_t tlv_tag; - ber_tlv_len_t tlv_len; - ber_tlv_len_t limit_len = -1; - int expect_00_terminators = 0; - int tlv_constr = -1; /* If CHOICE, opt_tlv_form is not given */ - int step = opt_ctx ? opt_ctx->step : 0; /* Where we left previously */ - int tagno; - - /* - * Make sure we didn't exceed the maximum stack size. - */ - if(_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx)) - RETURN(RC_FAIL); - - /* - * So what does all this implicit skip stuff mean? - * Imagine two types, - * A ::= [5] IMPLICIT T - * B ::= [2] EXPLICIT T - * Where T is defined as - * T ::= [4] IMPLICIT SEQUENCE { ... } - * - * Let's say, we are starting to decode type A, given the - * following TLV stream: <5> <0>. What does this mean? - * It means that the type A contains type T which is, - * in turn, empty. - * Remember though, that we are still in A. We cannot - * just pass control to the type T decoder. Why? Because - * the type T decoder expects <4> <0>, not <5> <0>. - * So, we must make sure we are going to receive <5> while - * still in A, then pass control to the T decoder, indicating - * that the tag <4> was implicitly skipped. The decoder of T - * hence will be prepared to treat <4> as valid tag, and decode - * it appropriately. - */ - - tagno = step /* Continuing where left previously */ - + (tag_mode==1?-1:0) - ; - ASN_DEBUG("ber_check_tags(%s, size=%ld, tm=%d, step=%d, tagno=%d)", - td->name, (long)size, tag_mode, step, tagno); - /* assert(td->tags_count >= 1) May not be the case for CHOICE or ANY */ - - if(tag_mode == 0 && tagno == td->tags_count) { - /* - * This must be the _untagged_ ANY type, - * which outermost tag isn't known in advance. - * Fetch the tag and length separately. - */ - tag_len = ber_fetch_tag(ptr, size, &tlv_tag); - switch(tag_len) { - case -1: RETURN(RC_FAIL); - case 0: RETURN(RC_WMORE); - } - tlv_constr = BER_TLV_CONSTRUCTED(ptr); - len_len = ber_fetch_length(tlv_constr, - (const char *)ptr + tag_len, size - tag_len, &tlv_len); - switch(len_len) { - case -1: RETURN(RC_FAIL); - case 0: RETURN(RC_WMORE); - } - ASN_DEBUG("Advancing %ld in ANY case", - (long)(tag_len + len_len)); - ADVANCE(tag_len + len_len); - } else { - assert(tagno < td->tags_count); /* At least one loop */ - } - for((void)tagno; tagno < td->tags_count; tagno++, step++) { - - /* - * Fetch and process T from TLV. - */ - tag_len = ber_fetch_tag(ptr, size, &tlv_tag); - ASN_DEBUG("Fetching tag from {%p,%ld}: " - "len %ld, step %d, tagno %d got %s", - ptr, (long)size, - (long)tag_len, step, tagno, - ber_tlv_tag_string(tlv_tag)); - switch(tag_len) { - case -1: RETURN(RC_FAIL); - case 0: RETURN(RC_WMORE); - } - - tlv_constr = BER_TLV_CONSTRUCTED(ptr); - - /* - * If {I}, don't check anything. - * If {I,B,C}, check B and C unless we're at I. - */ - if(tag_mode != 0 && step == 0) { - /* - * We don't expect tag to match here. - * It's just because we don't know how the tag - * is supposed to look like. - */ - } else { - assert(tagno >= 0); /* Guaranteed by the code above */ - if(tlv_tag != td->tags[tagno]) { - /* - * Unexpected tag. Too bad. - */ - ASN_DEBUG("Expected: %s, " - "expectation failed (tn=%d, tm=%d)", - ber_tlv_tag_string(td->tags[tagno]), - tagno, tag_mode - ); - RETURN(RC_FAIL); - } - } - - /* - * Attention: if there are more tags expected, - * ensure that the current tag is presented - * in constructed form (it contains other tags!). - * If this one is the last one, check that the tag form - * matches the one given in descriptor. - */ - if(tagno < (td->tags_count - 1)) { - if(tlv_constr == 0) { - ASN_DEBUG("tlv_constr = %d, expfail", - tlv_constr); - RETURN(RC_FAIL); - } - } else { - if(last_tag_form != tlv_constr - && last_tag_form != -1) { - ASN_DEBUG("last_tag_form %d != %d", - last_tag_form, tlv_constr); - RETURN(RC_FAIL); - } - } - - /* - * Fetch and process L from TLV. - */ - len_len = ber_fetch_length(tlv_constr, - (const char *)ptr + tag_len, size - tag_len, &tlv_len); - ASN_DEBUG("Fetchinig len = %ld", (long)len_len); - switch(len_len) { - case -1: RETURN(RC_FAIL); - case 0: RETURN(RC_WMORE); - } - - /* - * FIXME - * As of today, the chain of tags - * must either contain several indefinite length TLVs, - * or several definite length ones. - * No mixing is allowed. - */ - if(tlv_len == -1) { - /* - * Indefinite length. - */ - if(limit_len == -1) { - expect_00_terminators++; - } else { - ASN_DEBUG("Unexpected indefinite length " - "in a chain of definite lengths"); - RETURN(RC_FAIL); - } - ADVANCE(tag_len + len_len); - continue; - } else { - if(expect_00_terminators) { - ASN_DEBUG("Unexpected definite length " - "in a chain of indefinite lengths"); - RETURN(RC_FAIL); - } - } - - /* - * Check that multiple TLVs specify ever decreasing length, - * which is consistent. - */ - if(limit_len == -1) { - limit_len = tlv_len + tag_len + len_len; - if(limit_len < 0) { - /* Too great tlv_len value? */ - RETURN(RC_FAIL); - } - } else if(limit_len != tlv_len + tag_len + len_len) { - /* - * Inner TLV specifies length which is inconsistent - * with the outer TLV's length value. - */ - ASN_DEBUG("Outer TLV is %ld and inner is %ld", - (long)limit_len, (long)tlv_len); - RETURN(RC_FAIL); - } - - ADVANCE(tag_len + len_len); - - limit_len -= (tag_len + len_len); - if((ssize_t)size > limit_len) { - /* - * Make sure that we won't consume more bytes - * from the parent frame than the inferred limit. - */ - size = limit_len; - } - } - - if(opt_tlv_form) - *opt_tlv_form = tlv_constr; - if(expect_00_terminators) - *last_length = -expect_00_terminators; - else - *last_length = tlv_len; - - RETURN(RC_OK); -}