From: Fam Zheng Date: Wed, 26 Mar 2014 13:05:40 +0100 Subject: [PATCH] curl: check data size before memcpy to local buffer. (CVE-2014-0144) curl_read_cb is callback function for libcurl when data arrives. The data size passed in here is not guaranteed to be within the range of request we submitted, so we may overflow the guest IO buffer. Check the real size we have before memcpy to buffer to avoid overflow. Signed-off-by: Fam Zheng Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Signed-off-by: Stefan Hajnoczi (cherry picked from commit 6d4b9e55fc625514a38d27cff4b9933f617fa7dc) --- block/curl.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/block/curl.c b/block/curl.c index 82d39ff..14ae7e5 100644 --- a/block/curl.c +++ b/block/curl.c @@ -136,6 +136,11 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque) if (!s || !s->orig_buf) goto read_end; + if (s->buf_off >= s->buf_len) { + /* buffer full, read nothing */ + return 0; + } + realsize = MIN(realsize, s->buf_len - s->buf_off); memcpy(s->orig_buf + s->buf_off, ptr, realsize); s->buf_off += realsize;