Mercurial > dovecot > core-2.2
view src/lib/istream-base64-decoder.c @ 23017:c1d36f2575c7 default tip
lib-imap: Fix "Don't accept strings with NULs" cherry-pick
author | Timo Sirainen <timo.sirainen@open-xchange.com> |
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date | Thu, 29 Aug 2019 09:55:25 +0300 |
parents | cb108f786fb4 |
children |
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/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */ #include "lib.h" #include "buffer.h" #include "base64.h" #include "hex-binary.h" #include "istream-private.h" #include "istream-base64.h" struct base64_decoder_istream { struct istream_private istream; }; static int i_stream_read_parent(struct istream_private *stream) { size_t size; ssize_t ret; size = i_stream_get_data_size(stream->parent); if (size >= 4) return 1; /* we have less than one base64 block. see if there is more data available. */ ret = i_stream_read(stream->parent); if (ret <= 0) { stream->istream.stream_errno = stream->parent->stream_errno; stream->istream.eof = stream->parent->eof; return ret; } size = i_stream_get_data_size(stream->parent); i_assert(size != 0); return 1; } static int i_stream_base64_try_decode_block(struct base64_decoder_istream *bstream) { struct istream_private *stream = &bstream->istream; const unsigned char *data; size_t size, avail, buffer_avail, pos; buffer_t buf; data = i_stream_get_data(stream->parent, &size); if (size == 0) return 0; i_stream_try_alloc(stream, (size+3)/4*3, &avail); buffer_avail = stream->buffer_size - stream->pos; if ((size + 3) / 4 * 3 > buffer_avail) { /* can't fit everything to destination buffer. write as much as we can. */ size = (buffer_avail / 3) * 4; if (size == 0) return -2; } buffer_create_from_data(&buf, stream->w_buffer + stream->pos, buffer_avail); if (base64_decode(data, size, &pos, &buf) < 0) { io_stream_set_error(&stream->iostream, "Invalid base64 data: 0x%s", binary_to_hex(data+pos, I_MIN(size-pos, 8))); stream->istream.stream_errno = EINVAL; return -1; } stream->pos += buf.used; i_stream_skip(stream->parent, pos); return pos > 0 ? 1 : 0; } static ssize_t i_stream_base64_decoder_read(struct istream_private *stream) { struct base64_decoder_istream *bstream = (struct base64_decoder_istream *)stream; const unsigned char *data; size_t pre_count, post_count, size; int ret; do { ret = i_stream_read_parent(stream); if (ret <= 0) { if (ret < 0 && stream->istream.stream_errno == 0 && i_stream_get_data_size(stream->parent) > 0) { /* base64 input with a partial block */ data = i_stream_get_data(stream->parent, &size); io_stream_set_error(&stream->iostream, "base64 input ends with a partial block: 0x%s", binary_to_hex(data, size)); stream->istream.stream_errno = EINVAL; } return ret; } /* encode as many blocks as fits into destination buffer */ pre_count = stream->pos - stream->skip; while ((ret = i_stream_base64_try_decode_block(bstream)) > 0) ; post_count = stream->pos - stream->skip; } while (ret == 0 && pre_count == post_count); if (ret < 0 && pre_count == post_count) return ret; i_assert(post_count > pre_count); return post_count - pre_count; } static void i_stream_base64_decoder_seek(struct istream_private *stream, uoff_t v_offset, bool mark) { if (v_offset < stream->istream.v_offset) { /* seeking backwards - go back to beginning and seek forward from there. */ stream->parent_expected_offset = stream->parent_start_offset; stream->skip = stream->pos = 0; stream->istream.v_offset = 0; i_stream_seek(stream->parent, 0); } i_stream_default_seek_nonseekable(stream, v_offset, mark); } struct istream * i_stream_create_base64_decoder(struct istream *input) { struct base64_decoder_istream *bstream; bstream = i_new(struct base64_decoder_istream, 1); bstream->istream.max_buffer_size = input->real_stream->max_buffer_size; bstream->istream.read = i_stream_base64_decoder_read; bstream->istream.seek = i_stream_base64_decoder_seek; bstream->istream.istream.readable_fd = FALSE; bstream->istream.istream.blocking = input->blocking; bstream->istream.istream.seekable = input->seekable; return i_stream_create(&bstream->istream, input, i_stream_get_fd(input)); }