svn commit: r292330 - head/lib/libfetch

[Dag-Erling Smørgrav]

Author: des
Date: Wed Dec 16 09:17:07 2015
New Revision: 292330
URL: https://svnweb.freebsd.org/changeset/base/292330

Log:
  Reset bufpos to 0 immediately after refilling the buffer.  Otherwise, we
  risk leaving the connection in an indeterminate state if the server fails
  to send a chunk delimiter.  Depending on the application and on the sizes
  of the preceding chunks, the result can be anything from missing data to a
  segfault.  With this patch, it will be reported as a protocol error.
  
  PR:		204771
  MFC after:	1 week

Modified:
  head/lib/libfetch/http.c

Modified: head/lib/libfetch/http.c
==============================================================================
--- head/lib/libfetch/http.c	Wed Dec 16 09:16:06 2015	(r292329)
+++ head/lib/libfetch/http.c	Wed Dec 16 09:17:07 2015	(r292330)
@@ -246,8 +246,9 @@ http_fillbuf(struct httpio *io, size_t l
 		io->error = errno;
 		return (-1);
 	}
+	io->bufpos = 0;
 	io->buflen = nbytes;
-	io->chunksize -= io->buflen;
+	io->chunksize -= nbytes;
 
 	if (io->chunksize == 0) {
 		if (fetch_read(io->conn, &ch, 1) != 1 || ch != '\r' ||
@@ -255,8 +256,6 @@ http_fillbuf(struct httpio *io, size_t l
 			return (-1);
 	}
 
-	io->bufpos = 0;
-
 	return (io->buflen);
 }