51 lines
1.8 KiB
Diff
51 lines
1.8 KiB
Diff
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From 5acd23f4581da58683f3cf5e36cb71bbe4070bd7 Mon Sep 17 00:00:00 2001
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From: Jouni Malinen <j@w1.fi>
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Date: Tue, 28 Apr 2015 17:08:33 +0300
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Subject: [PATCH] WPS: Fix HTTP chunked transfer encoding parser
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strtoul() return value may end up overflowing the int h->chunk_size and
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resulting in a negative value to be stored as the chunk_size. This could
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result in the following memcpy operation using a very large length
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argument which would result in a buffer overflow and segmentation fault.
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This could have been used to cause a denial service by any device that
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has been authorized for network access (either wireless or wired). This
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would affect both the WPS UPnP functionality in a WPS AP (hostapd with
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upnp_iface parameter set in the configuration) and WPS ER
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(wpa_supplicant with WPS_ER_START control interface command used).
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Validate the parsed chunk length value to avoid this. In addition to
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rejecting negative values, we can also reject chunk size that would be
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larger than the maximum configured body length.
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Thanks to Kostya Kortchinsky of Google security team for discovering and
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reporting this issue.
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Signed-off-by: Jouni Malinen <j@w1.fi>
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Signed-off-by: Baruch Siach <baruch@tkos.co.il>
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---
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src/wps/httpread.c | 7 +++++++
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1 file changed, 7 insertions(+)
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diff --git a/src/wps/httpread.c b/src/wps/httpread.c
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index 2f08f37275c0..d2855e32fd0f 100644
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--- a/src/wps/httpread.c
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+++ b/src/wps/httpread.c
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@@ -533,6 +533,13 @@ static void httpread_read_handler(int sd, void *eloop_ctx, void *sock_ctx)
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if (!isxdigit(*cbp))
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goto bad;
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h->chunk_size = strtoul(cbp, NULL, 16);
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+ if (h->chunk_size < 0 ||
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+ h->chunk_size > h->max_bytes) {
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+ wpa_printf(MSG_DEBUG,
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+ "httpread: Invalid chunk size %d",
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+ h->chunk_size);
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+ goto bad;
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+ }
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/* throw away chunk header
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* so we have only real data
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*/
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--
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2.1.4
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