diff options
Diffstat (limited to 'src/lib/istream-jsonstr.c')
| -rw-r--r-- | src/lib/istream-jsonstr.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/src/lib/istream-jsonstr.c b/src/lib/istream-jsonstr.c new file mode 100644 index 0000000..727f21c --- /dev/null +++ b/src/lib/istream-jsonstr.c @@ -0,0 +1,217 @@ +/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */ + +#include "lib.h" +#include "buffer.h" +#include "hex-dec.h" +#include "unichar.h" +#include "istream-private.h" +#include "istream-jsonstr.h" + +#define MAX_UTF8_LEN 6 + +struct jsonstr_istream { + struct istream_private istream; + + /* The end '"' was found */ + bool str_end:1; +}; + +static int +i_stream_jsonstr_read_parent(struct jsonstr_istream *jstream, + unsigned int min_bytes) +{ + struct istream_private *stream = &jstream->istream; + size_t size, avail; + ssize_t ret; + + size = i_stream_get_data_size(stream->parent); + while (size < min_bytes) { + ret = i_stream_read_memarea(stream->parent); + if (ret <= 0) { + if (ret == -2) { + /* tiny parent buffer size - shouldn't happen */ + return -2; + } + stream->istream.stream_errno = + stream->parent->stream_errno; + stream->istream.eof = stream->parent->eof; + if (ret == -1 && stream->istream.stream_errno == 0) { + io_stream_set_error(&stream->iostream, + "EOF before trailing <\"> was seen"); + stream->istream.stream_errno = EPIPE; + } + return ret; + } + size = i_stream_get_data_size(stream->parent); + } + + if (!i_stream_try_alloc(stream, size, &avail)) + return -2; + return 1; +} + +static int +i_stream_json_unescape(const unsigned char *src, size_t len, + unsigned char *dest, + unsigned int *src_size_r, unsigned int *dest_size_r) +{ + switch (*src) { + case '"': + case '\\': + case '/': + *dest = *src; + break; + case 'b': + *dest = '\b'; + break; + case 'f': + *dest = '\f'; + break; + case 'n': + *dest = '\n'; + break; + case 'r': + *dest = '\r'; + break; + case 't': + *dest = '\t'; + break; + case 'u': { + char chbuf[5] = {0}; + unichar_t chr,chr2 = 0; + buffer_t buf; + if (len < 5) + return 5; + buffer_create_from_data(&buf, dest, MAX_UTF8_LEN); + memcpy(chbuf, src+1, 4); + if (str_to_uint32_hex(chbuf, &chr)<0) + return -1; + if (UTF16_VALID_LOW_SURROGATE(chr)) + return -1; + /* if we encounter surrogate, we need another \\uxxxx */ + if (UTF16_VALID_HIGH_SURROGATE(chr)) { + if (len < 5+2+4) + return 5+2+4; + if (src[5] != '\\' && src[6] != 'u') + return -1; + memcpy(chbuf, src+7, 4); + if (str_to_uint32_hex(chbuf, &chr2)<0) + return -1; + if (!UTF16_VALID_LOW_SURROGATE(chr2)) + return -1; + chr = uni_join_surrogate(chr, chr2); + } + if (!uni_is_valid_ucs4(chr)) + return -1; + uni_ucs4_to_utf8_c(chr, &buf); + *src_size_r = 5 + (chr2>0?6:0); + *dest_size_r = buf.used; + return 0; + } + default: + return -1; + } + *src_size_r = 1; + *dest_size_r = 1; + return 0; +} + +static ssize_t i_stream_jsonstr_read(struct istream_private *stream) +{ + struct jsonstr_istream *jstream = + container_of(stream, struct jsonstr_istream, istream); + const unsigned char *data; + unsigned int srcskip, destskip, extra; + size_t i, dest, size; + ssize_t ret, ret2; + + if (jstream->str_end) { + stream->istream.eof = TRUE; + return -1; + } + + ret = i_stream_jsonstr_read_parent(jstream, 1); + if (ret <= 0) + return ret; + + /* @UNSAFE */ + dest = stream->pos; + extra = 0; + + data = i_stream_get_data(stream->parent, &size); + for (i = 0; i < size && dest < stream->buffer_size; ) { + if (data[i] == '"') { + jstream->str_end = TRUE; + if (dest == stream->pos) { + stream->istream.eof = TRUE; + return -1; + } + break; + } else if (data[i] == '\\') { + if (i+1 == size) { + /* not enough input for \x */ + extra = 1; + break; + } + if (data[i+1] == 'u' && stream->buffer_size - dest < MAX_UTF8_LEN) { + /* UTF8 output is max. 6 chars */ + if (dest == stream->pos) + return -2; + break; + } + i++; + if ((ret2 = i_stream_json_unescape(data + i, size - i, + stream->w_buffer + dest, + &srcskip, &destskip)) < 0) { + /* invalid string */ + io_stream_set_error(&stream->iostream, + "Invalid JSON string"); + stream->istream.stream_errno = EINVAL; + return -1; + } else if (ret2 > 0) { + /* we need to get more bytes, do not consume + escape slash */ + i--; + extra = ret2; + break; + } + i += srcskip; + i_assert(i <= size); + dest += destskip; + i_assert(dest <= stream->buffer_size); + } else { + stream->w_buffer[dest++] = data[i]; + i++; + } + } + i_stream_skip(stream->parent, i); + + ret = dest - stream->pos; + if (ret == 0) { + /* not enough input */ + i_assert(i == 0); + i_assert(extra > 0); + ret = i_stream_jsonstr_read_parent(jstream, extra+1); + if (ret <= 0) + return ret; + return i_stream_jsonstr_read(stream); + } + i_assert(ret > 0); + stream->pos = dest; + return ret; +} + +struct istream *i_stream_create_jsonstr(struct istream *input) +{ + struct jsonstr_istream *dstream; + + dstream = i_new(struct jsonstr_istream, 1); + dstream->istream.max_buffer_size = input->real_stream->max_buffer_size; + dstream->istream.read = i_stream_jsonstr_read; + + dstream->istream.istream.readable_fd = FALSE; + dstream->istream.istream.blocking = input->blocking; + dstream->istream.istream.seekable = FALSE; + return i_stream_create(&dstream->istream, input, + i_stream_get_fd(input), 0); +} |