sm: Another partly rewrite of minip12.c
* sm/minip12.c (struct tlv_ctx_s): Add origbuffer and origbufsize. Remove pop_count. Rename offset to length. (dump_tag_info, _dump_tag_info): Rewrite. (dump_tlv_ctx, _dump_tlv_ctx): Rewrite. (tlv_new): Init origbuffer. (_tlv_peek): Add arg ti. (tlv_peek): New. (tlv_peek_null): New. (_tlv_push): Rewrite. (_tlv_pop): Rewrite. (tlv_next): New macro. Move old code to ... (_tlv_next): this. Add arg lno. Pop remaining end tags. (tlv_popped): Remove. (tlv_expect_object): Handle ndef. (tlv_expect_octet_string): Ditto. (parse_bag_encrypted_data): Use nesting level to control the inner loop. (parse_shrouded_key_bag): Likewise. (parse_bag_data): Handle surplus octet strings. (p12_parse): Ditto. * sm/minip12.c (decrypt_block): Strip the padding. (tlv_expect_top_sequence): Remove. Replace callers by tlv_expect_sequence. * tests/cms/samplekeys/t6752-ov-user-ff.p12: New sample key. * tests/cms/samplekeys/Description-p12: Add its description
This patch improves the BER parser by simplifying it. Now tlv_next
pops off and thus closes all containers regardless on whether they are
length bounded or ndef. tlv_set_pending is now always used to undo
the effect of a tlv_next in a loop condition which was terminated by a
nesting level change.
Instead of using the length as seen in the decrypted container we now
remove the padding and let the BER parser do its work. This might
have a negative effect on pkcs#12 objects which are not correctly
padded but we don't have any example of such broken objects.
- GnuPG-bug-id: T6752