From e1af2dc6cab081fd55290b2c5b05f67c229385b0 Mon Sep 17 00:00:00 2001 From: Erik de Castro Lopo Date: Fri, 14 Apr 2017 15:19:16 +1000 Subject: [PATCH] src/flac.c: Fix a buffer read overflow A file (generated by a fuzzer) which increased the number of channels from one frame to the next could cause a read beyond the end of the buffer provided by libFLAC. Only option is to abort the read. Change-Id: Ibf8626f9a485c4b0a5db219d413651444f56e382 Closes: https://github.com/erikd/libsndfile/issues/231 --- src/flac.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/flac.c b/src/flac.c index 2992f4c..ddbb015 100644 --- a/src/flac.c +++ b/src/flac.c @@ -169,6 +169,14 @@ flac_buffer_copy (SF_PRIVATE *psf) const int32_t* const *buffer = pflac->wbuffer ; unsigned i = 0, j, offset, channels, len ; + if (psf->sf.channels != (int) frame->header.channels) + { psf_log_printf (psf, "Error: FLAC frame changed from %d to %d channels\n" + "Nothing to do but to error out.\n" , + psf->sf.channels, frame->header.channels) ; + psf->error = SFE_FLAC_CHANNEL_COUNT_CHANGED ; + return 0 ; + } ; + /* ** frame->header.blocksize is variable and we're using a constant blocksize ** of FLAC__MAX_BLOCK_SIZE. @@ -202,7 +210,6 @@ flac_buffer_copy (SF_PRIVATE *psf) return 0 ; } ; - len = SF_MIN (pflac->len, frame->header.blocksize) ; if (pflac->remain % channels != 0) @@ -436,7 +443,7 @@ sf_flac_meta_callback (const FLAC__StreamDecoder * UNUSED (decoder), const FLAC_ { case FLAC__METADATA_TYPE_STREAMINFO : if (psf->sf.channels > 0 && psf->sf.channels != (int) metadata->data.stream_info.channels) { psf_log_printf (psf, "Error: FLAC stream changed from %d to %d channels\n" - "Nothing to be but to error out.\n" , + "Nothing to do but to error out.\n" , psf->sf.channels, metadata->data.stream_info.channels) ; psf->error = SFE_FLAC_CHANNEL_COUNT_CHANGED ; return ; -- 2.7.4