[PATCH 1/8] Add utilities for encoding BTLVs and CTLVs.

This version is simplified and avoids memcpy'ing when encoding BER-TLVs, at the cost of robustness. Every BER-TLV now needs to be closed using .._next() or .._optimize() before it's valid. --- src/simutil.c | 316 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ src/simutil.h | 50 +++++++++ 2 files changed, 366 insertions(+), 0 deletions(-) diff --git a/src/simutil.c b/src/simutil.c index 941c551..f0876d3 100644 --- a/src/simutil.c +++ b/src/simutil.c @@ -486,6 +486,322 @@ static const guint8 *ber_tlv_find_by_tag(const guint8 *pdu, guint8 in_tag, return NULL; } +#define MAX_BER_TLV_HEADER 8 + +gboolean ber_tlv_builder_init(struct ber_tlv_builder *builder, + unsigned char *pdu, unsigned int size) +{ + if (size < MAX_BER_TLV_HEADER) + return FALSE; + + builder->pdu = pdu; + builder->pos = 0; + builder->max = size; + builder->parent = NULL; + builder->tag = 0; + builder->len = 0; + + return TRUE; +} + +static void ber_tlv_builder_write_header(struct ber_tlv_builder *builder) +{ + int header_len = 0; + int start = builder->pos + MAX_BER_TLV_HEADER; + + /* Write length at end of the header space */ + if (builder->len <= 0x7f) + builder->pdu[start - ++header_len] = builder->len; + else { + while (builder->len >> (header_len * 8)) { + builder->pdu[start - 1 - header_len] = + builder->len >> (header_len * 8); + header_len++; + } + builder->pdu[start - 1 - header_len] = 0x80 + header_len; + header_len++; + } + + /* Write the tag before length */ + if (builder->tag < 0x1f) + builder->pdu[start - ++header_len] = + (builder->class << 6) | + (builder->encoding << 5) | + builder->tag; + else { + int i = 0; + + while (builder->tag >> (i * 7)) { + builder->pdu[start - ++header_len] = + i ? 0x80 | (builder->tag >> (i * 7)) : + (builder->tag & 0x7f); + i++; + } + + builder->pdu[start - ++header_len] = + (builder->class << 6) | (builder->encoding << 5) | 0x1f; + } + + /* Pad with stuff bytes */ + if (header_len < MAX_BER_TLV_HEADER) + memset(builder->pdu + builder->pos, 0xff, + MAX_BER_TLV_HEADER - header_len); +} + +gboolean ber_tlv_builder_next(struct ber_tlv_builder *builder) +{ + ber_tlv_builder_write_header(builder); + + builder->pos += MAX_BER_TLV_HEADER + builder->len; + + if (builder->pos + MAX_BER_TLV_HEADER > builder->max) + return FALSE; + + if (builder->parent) + if (ber_tlv_builder_set_length(builder->parent, builder->pos + + MAX_BER_TLV_HEADER) == FALSE) + return FALSE; + + builder->tag = 0; + builder->len = 0; + + return TRUE; +} + +gboolean ber_tlv_builder_set_tag(struct ber_tlv_builder *builder, + enum ber_tlv_data_type class, + enum ber_tlv_data_encoding_type encoding, + unsigned int new_tag) +{ + builder->class = class; + builder->encoding = encoding; + builder->tag = new_tag; + + return TRUE; +} + +/* Resize the TLV because the content of Value field needs more space. If + * this TLV is part of another TLV, resize that one too. */ +gboolean ber_tlv_builder_set_length(struct ber_tlv_builder *builder, + unsigned int new_len) +{ + if (builder->pos + MAX_BER_TLV_HEADER + new_len > builder->max) + return FALSE; + + if (builder->parent) + if (ber_tlv_builder_set_length(builder->parent, + builder->pos + MAX_BER_TLV_HEADER + + new_len) == FALSE) + return FALSE; + + builder->len = new_len; + + return TRUE; +} + +unsigned char *ber_tlv_builder_get_data(struct ber_tlv_builder *builder) +{ + return builder->pdu + builder->pos + MAX_BER_TLV_HEADER; +} + +gboolean ber_tlv_builder_recurse(struct ber_tlv_builder *builder, + struct ber_tlv_builder *recurse) +{ + unsigned char *end = builder->pdu + builder->max; + unsigned char *data = ber_tlv_builder_get_data(builder); + + if (ber_tlv_builder_init(recurse, data, end - data) == FALSE) + return FALSE; + + recurse->parent = builder; + + return TRUE; +} + +gboolean ber_tlv_builder_recurse_comprehension(struct ber_tlv_builder *builder, + struct comprehension_tlv_builder *recurse) +{ + unsigned char *end = builder->pdu + builder->max; + unsigned char *data = ber_tlv_builder_get_data(builder); + + if (comprehension_tlv_builder_init(recurse, data, end - data) == FALSE) + return FALSE; + + recurse->parent = builder; + + return TRUE; +} + +void ber_tlv_builder_optimize(struct ber_tlv_builder *builder, + unsigned char **pdu, unsigned int *len) +{ + ber_tlv_builder_write_header(builder); + + if (pdu == NULL) + return; + + *len = builder->pos + MAX_BER_TLV_HEADER + builder->len; + *pdu = builder->pdu; + + while (**pdu == 0xff) { + (*len)--; + (*pdu)++; + } +} + +gboolean comprehension_tlv_builder_init( + struct comprehension_tlv_builder *builder, + unsigned char *pdu, unsigned int size) +{ + if (size < 2) + return FALSE; + + builder->pdu = pdu; + builder->pos = 0; + builder->max = size; + builder->parent = NULL; + + builder->pdu[0] = 0; + builder->pdu[1] = 0; + + return TRUE; +} + +static inline unsigned int comprehension_tlv_get_tag_len(unsigned char *start) +{ + return bit_field(*start, 0, 7) == 0x7f ? 3 : 1; +} + +static inline unsigned int comprehension_tlv_get_len_len(unsigned char *start) +{ + return *start >= 0x80 ? *start - 0x7f : 1; +} + +gboolean comprehension_tlv_builder_next( + struct comprehension_tlv_builder *builder) +{ + unsigned int taglen = + comprehension_tlv_get_tag_len(builder->pdu + builder->pos); + unsigned int lenlen = 1; + unsigned int len = builder->pdu[builder->pos + taglen]; + + if (len >= 0x80) { + unsigned int extended_bytes = len - 0x80; + unsigned int i; + + for (len = 0, i = 1; i <= extended_bytes; i++) + len = (len << 8) | + builder->pdu[builder->pos + taglen + i]; + + lenlen += extended_bytes; + } + + if (builder->pos + taglen + lenlen + len + 2 > builder->max) + return FALSE; + + builder->pos += taglen + lenlen + len; + builder->pdu[builder->pos + 0] = 0; /* Tag */ + builder->pdu[builder->pos + 1] = 0; /* Length */ + + return TRUE; +} + +gboolean comprehension_tlv_builder_set_tag( + struct comprehension_tlv_builder *builder, + gboolean cr, unsigned short tag) +{ + if (tag < 0x7f) + builder->pdu[builder->pos] = (cr ? 0x80 : 0x00) | tag; + else { + if (builder->pos + 4 > builder->max) + return FALSE; + + builder->pdu[builder->pos] = 0x7f; + builder->pdu[builder->pos + 1] = (cr ? 0x80 : 0) | (tag >> 8); + builder->pdu[builder->pos + 2] = tag & 0xff; + builder->pdu[builder->pos + 3] = 0; + } + + return TRUE; +} + +/* Resize the TLV because the content of Value field needs more space. If + * this TLV is part of another TLV, resize that one too. */ +gboolean comprehension_tlv_builder_set_length( + struct comprehension_tlv_builder *builder, + unsigned int new_len) +{ + unsigned char *tlv = builder->pdu + builder->pos; + unsigned int taglen = comprehension_tlv_get_tag_len(tlv); + unsigned int lenlen = 1, new_lenlen = 1; + unsigned int len = tlv[taglen]; + unsigned int ctlv_len, new_ctlv_len; + + /* How much space do we occupy now */ + if (len >= 0x80) { + unsigned int extended_bytes = len - 0x80; + unsigned int i; + + for (len = 0, i = 1; i <= extended_bytes; i++) + len = (len << 8) | tlv[taglen + i]; + + lenlen += extended_bytes; + } + + ctlv_len = taglen + lenlen + len; + + /* How much do we need */ + if (new_len >= 0x80) { + unsigned int extended_bytes = 0; + while (new_len >> (extended_bytes * 8)) + extended_bytes += 1; + new_lenlen += extended_bytes; + } + + new_ctlv_len = taglen + new_lenlen + new_len; + + /* Check there is enough space */ + if (builder->pos + new_ctlv_len > builder->max) + return FALSE; + + if (builder->parent) + if (ber_tlv_builder_set_length(builder->parent, builder->pos + + new_ctlv_len) == FALSE) + return FALSE; + + len = MIN(len, new_len); + if (len > 0 && new_lenlen != lenlen) + memmove(tlv + taglen + new_lenlen, tlv + taglen + lenlen, len); + + /* Write new length */ + if (new_len < 0x80) + tlv[taglen] = new_len; + else { + unsigned int extended_bytes = 0; + unsigned int i; + while (new_len >> (extended_bytes * 8)) + extended_bytes += 1; + + for (i = 1; i <= extended_bytes; i++) + tlv[taglen + i] = + (new_len >> ((extended_bytes - i) * 8)) & 0xff; + + tlv[taglen] = 0x80 + extended_bytes; + } + + return TRUE; +} + +unsigned char *comprehension_tlv_builder_get_data( + struct comprehension_tlv_builder *builder) +{ + unsigned char *tlv = builder->pdu + builder->pos; + unsigned int taglen = comprehension_tlv_get_tag_len(tlv); + unsigned int lenlen = comprehension_tlv_get_len_len(tlv + taglen); + + return tlv + taglen + lenlen; +} + static char *sim_network_name_parse(const unsigned char *buffer, int length, gboolean *add_ci) { diff --git a/src/simutil.h b/src/simutil.h index 7590cca..42d4168 100644 --- a/src/simutil.h +++ b/src/simutil.h @@ -114,6 +114,25 @@ struct ber_tlv_iter { const unsigned char *data; }; +struct ber_tlv_builder { + unsigned int max; + unsigned int pos; + unsigned char *pdu; + struct ber_tlv_builder *parent; + + unsigned int tag; + enum ber_tlv_data_type class; + enum ber_tlv_data_encoding_type encoding; + unsigned int len; +}; + +struct comprehension_tlv_builder { + unsigned int max; + unsigned int pos; + unsigned char *pdu; + struct ber_tlv_builder *parent; +}; + void simple_tlv_iter_init(struct simple_tlv_iter *iter, const unsigned char *pdu, unsigned int len); gboolean simple_tlv_iter_next(struct simple_tlv_iter *iter); @@ -132,6 +151,20 @@ unsigned int comprehension_tlv_iter_get_length( const unsigned char *comprehension_tlv_iter_get_data( struct comprehension_tlv_iter *iter); +gboolean comprehension_tlv_builder_init( + struct comprehension_tlv_builder *builder, + unsigned char *pdu, unsigned int size); +gboolean comprehension_tlv_builder_next( + struct comprehension_tlv_builder *builder); +gboolean comprehension_tlv_builder_set_tag( + struct comprehension_tlv_builder *builder, + gboolean cr, unsigned short tag); +gboolean comprehension_tlv_builder_set_length( + struct comprehension_tlv_builder *builder, + unsigned int len); +unsigned char *comprehension_tlv_builder_get_data( + struct comprehension_tlv_builder *builder); + void ber_tlv_iter_init(struct ber_tlv_iter *iter, const unsigned char *pdu, unsigned int len); /* @@ -164,6 +197,23 @@ void ber_tlv_iter_recurse_simple(struct ber_tlv_iter *iter, void ber_tlv_iter_recurse_comprehension(struct ber_tlv_iter *iter, struct comprehension_tlv_iter *recurse); +gboolean ber_tlv_builder_init(struct ber_tlv_builder *builder, + unsigned char *pdu, unsigned int size); +gboolean ber_tlv_builder_set_tag(struct ber_tlv_builder *builder, + enum ber_tlv_data_type class, + enum ber_tlv_data_encoding_type encoding, + unsigned int new_tag); +gboolean ber_tlv_builder_set_length(struct ber_tlv_builder *builder, + unsigned int len); +unsigned char *ber_tlv_builder_get_data(struct ber_tlv_builder *builder); +gboolean ber_tlv_builder_next(struct ber_tlv_builder *builder); +gboolean ber_tlv_builder_recurse(struct ber_tlv_builder *builder, + struct ber_tlv_builder *recurse); +gboolean ber_tlv_builder_recurse_comprehension(struct ber_tlv_builder *builder, + struct comprehension_tlv_builder *recurse); +void ber_tlv_builder_optimize(struct ber_tlv_builder *builder, + unsigned char **pdu, unsigned int *len); + struct sim_eons *sim_eons_new(int pnn_records); void sim_eons_add_pnn_record(struct sim_eons *eons, int record, const guint8 *tlv, int length); -- 1.6.1