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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 09:51:24 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 09:51:24 +0000
commitf7548d6d28c313cf80e6f3ef89aed16a19815df1 (patch)
treea3f6f2a3f247293bee59ecd28e8cd8ceb6ca064a /src/lib/istream-base64-decoder.c
parentInitial commit. (diff)
downloaddovecot-f7548d6d28c313cf80e6f3ef89aed16a19815df1.tar.xz
dovecot-f7548d6d28c313cf80e6f3ef89aed16a19815df1.zip
Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/lib/istream-base64-decoder.c')
-rw-r--r--src/lib/istream-base64-decoder.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/src/lib/istream-base64-decoder.c b/src/lib/istream-base64-decoder.c
new file mode 100644
index 0000000..6eaa842
--- /dev/null
+++ b/src/lib/istream-base64-decoder.c
@@ -0,0 +1,171 @@
+/* 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;
+
+ struct base64_decoder decoder;
+};
+
+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_memarea(stream->parent);
+ if (ret <= 0) {
+ stream->istream.stream_errno = stream->parent->stream_errno;
+ 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, pos;
+ buffer_t buf;
+
+ data = i_stream_get_data(stream->parent, &size);
+ if (size == 0)
+ return 0;
+
+ if (!i_stream_try_alloc(stream, (size+3)/4*3, &avail))
+ return -2;
+
+ buffer_create_from_data(&buf, stream->w_buffer + stream->pos, avail);
+ if (base64_decode_more(&bstream->decoder, 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 void
+i_stream_base64_finish_decode(struct base64_decoder_istream *bstream)
+{
+ struct istream_private *stream = &bstream->istream;
+
+ i_assert(i_stream_get_data_size(stream->parent) == 0);
+
+ if (base64_decode_finish(&bstream->decoder) < 0) {
+ io_stream_set_error(&stream->iostream,
+ "Base64 data ends prematurely");
+ stream->istream.stream_errno = EPIPE;
+ }
+}
+
+static ssize_t i_stream_base64_decoder_read(struct istream_private *stream)
+{
+ struct base64_decoder_istream *bstream =
+ container_of(stream, struct base64_decoder_istream, istream);
+ size_t pre_count, post_count;
+ int ret;
+
+ if (base64_decode_is_finished(&bstream->decoder)) {
+ stream->istream.eof = TRUE;
+ return -1;
+ }
+
+ do {
+ ret = i_stream_read_parent(stream);
+ if (ret == 0)
+ return 0;
+ if (ret < 0 && ret != -2) {
+ if (stream->istream.stream_errno != 0)
+ return -1;
+ if (i_stream_get_data_size(stream->parent) == 0) {
+ i_stream_base64_finish_decode(bstream);
+ stream->istream.eof = TRUE;
+ return -1;
+ }
+ }
+
+ /* 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)
+{
+ struct base64_decoder_istream *bstream =
+ container_of(stream, struct base64_decoder_istream, istream);
+
+ 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);
+
+ base64_decode_reset(&bstream->decoder);
+ }
+ i_stream_default_seek_nonseekable(stream, v_offset, mark);
+}
+
+static struct istream *
+i_stream_create_base64_decoder_common(const struct base64_scheme *b64,
+ 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;
+
+ base64_decode_init(&bstream->decoder, b64, 0);
+
+ return i_stream_create(&bstream->istream, input,
+ i_stream_get_fd(input), 0);
+}
+
+struct istream *
+i_stream_create_base64_decoder(struct istream *input)
+{
+ return i_stream_create_base64_decoder_common(&base64_scheme, input);
+}
+
+struct istream *
+i_stream_create_base64url_decoder(struct istream *input)
+{
+ return i_stream_create_base64_decoder_common(&base64url_scheme, input);
+}