Fix stack overflow in HTTP protocol handling (CVE-2017-13089)

* src/http.c (skip_short_body): Return error on negative chunk size

Reported-by: Antti Levomäki, Christian Jalio, Joonas Pihlaja from Forcepoint
Reported-by: Juhani Eronen from Finnish National Cyber Security Centre

1 files changed, 3 insertions, 0 deletions

diff --git a/src/http.c b/src/http.c
index 5536768..dc31823 100644
--- a/src/http.c
+++ b/src/http.c
@@ -973,6 +973,9 @@ skip_short_body (int fd, wgint contlen, bool chunked)
               remaining_chunk_size = strtol (line, &endl, 16);
               xfree (line);
 
+              if (remaining_chunk_size < 0)
+                return false;
+
               if (remaining_chunk_size == 0)
                 {
                   line = fd_read_line (fd);