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From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
Date: Wed, 13 Dec 2017 13:38:33 +0100
Subject: [PATCH 02/41] fw_cfg: prevent selector key conflict
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RH-Author: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: <20171213133912.26176-3-marcandre.lureau@redhat.com>
Patchwork-id: 78352
O-Subject: [RHEL-7.5 qemu-kvm PATCH v3 02/41] fw_cfg: prevent selector key conflict
Bugzilla: 1411490
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

From: "Gabriel L. Somlo" <somlo@cmu.edu>

Enforce a single assignment of data for each distinct selector key.

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

(cherry picked from commit 0f9b214139d11ef058fa0f1c11c89e94fa6ef95d)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/nvram/fw_cfg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 9d7b99e..149e2fb 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -380,6 +380,7 @@ static void fw_cfg_add_bytes_read_callback(FWCfgState *s, uint16_t key,
     key &= FW_CFG_ENTRY_MASK;
 
     assert(key < FW_CFG_MAX_ENTRY && len < UINT32_MAX);
+    assert(s->entries[arch][key].data == NULL); /* avoid key conflict */
 
     s->entries[arch][key].data = data;
     s->entries[arch][key].len = (uint32_t)len;
-- 
1.8.3.1