Add missing assignment in DataSource::discard_next

Reported on the mailing list by Falko

2 files changed, 5 insertions, 0 deletions

diff --git a/doc/news.rst b/doc/news.rst
index e340033c4..9ddca58bd 100644
--- a/doc/news.rst
+++ b/doc/news.rst
@@ -34,6 +34,10 @@ Version 1.11.26, Not Yet Released
 
 * Add support for RSA-KEM from ISO 18033-2
 
+* Fix a bug in DataSource::discard_next() which could cause either an
+  infinite loop or the discarding of an incorrect number of bytes.
+  Reported on mailing list by Falko Strenzke.
+
 * Avoid calling memcpy, memset, or memmove with a length of zero to
   avoid undefined behavior, as calling these functions with an invalid
   or null pointer, even with a length of zero, is invalid. Often there
diff --git a/src/lib/utils/data_src.cpp b/src/lib/utils/data_src.cpp
index 4e0725943..b79f83d40 100644
--- a/src/lib/utils/data_src.cpp
+++ b/src/lib/utils/data_src.cpp
@@ -41,6 +41,7 @@ size_t DataSource::discard_next(size_t n)
       {
       const size_t got = this->read(buf, std::min(n, sizeof(buf)));
       discarded += got;
+      n -= got;
 
       if(got == 0)
          break;