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From e64c6e9054f97e5894d875380d241124d8f0bcc9 Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Tue, 25 Mar 2014 14:23:26 +0100
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Subject: [PATCH 19/49] curl: check data size before memcpy to local buffer. (CVE-2014-0144)
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1395753835-7591-20-git-send-email-kwolf@redhat.com>
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Patchwork-id: n/a
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O-Subject: [virt-devel] [EMBARGOED RHEL-7.0 qemu-kvm PATCH 19/48] curl: check data size before memcpy to local buffer. (CVE-2014-0144)
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Bugzilla: 1079455
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RH-Acked-by: Jeff Cody <jcody@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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From: Fam Zheng <famz@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079455
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Upstream status: Embargoed
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curl_read_cb is callback function for libcurl when data arrives. The
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data size passed in here is not guaranteed to be within the range of
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request we submitted, so we may overflow the guest IO buffer. Check the
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real size we have before memcpy to buffer to avoid overflow.
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 block/curl.c |    5 +++++
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 1 files changed, 5 insertions(+), 0 deletions(-)
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diff --git a/block/curl.c b/block/curl.c
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index 1b0fcf1..b3d948e 100644
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--- a/block/curl.c
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+++ b/block/curl.c
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@@ -134,6 +134,11 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
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     if (!s || !s->orig_buf)
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         goto read_end;
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+    if (s->buf_off >= s->buf_len) {
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+        /* buffer full, read nothing */
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+        return 0;
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+    }
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+    realsize = MIN(realsize, s->buf_len - s->buf_off);
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     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
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     s->buf_off += realsize;
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-- 
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1.7.1
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