| From 5d12c17191e042a57e02749cedc55104a8251ac3 Mon Sep 17 00:00:00 2001 |
| From: Miroslav Rezanina <mrezanin@redhat.com> |
| Date: Thu, 21 Jan 2016 07:17:43 +0100 |
| Subject: [PATCH] fw_cfg: add check to validate current entry value |
| (CVE-2016-1714) |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| Message-id: <1453360663-5066-1-git-send-email-mrezanin@redhat.com> |
| Patchwork-id: 68834 |
| O-Subject: [RHEL-7.2.z/RHEL-7.3 qemu-kvm PATCH] fw_cfg: add check to validate current entry value (CVE-2016-1714) |
| Bugzilla: 1298047 |
| RH-Acked-by: Laurent Vivier <lvivier@redhat.com> |
| RH-Acked-by: Laszlo Ersek <lersek@redhat.com> |
| RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com> |
| |
| From: Prasad J Pandit <pjp@fedoraproject.org> |
| |
| When processing firmware configurations, an OOB r/w access occurs |
| if 's->cur_entry' is set to be invalid(FW_CFG_INVALID=0xffff). |
| Add a check to validate 's->cur_entry' to avoid such access. |
| |
| This patch is based on upstream commit 66f8fd9dda312191b78d2a2ba2848bcee76127a2 |
| Author: Gabriel L. Somlo <somlo@cmu.edu> |
| Date: Thu Nov 5 09:32:50 2015 -0500 |
| |
| fw_cfg: avoid calculating invalid current entry pointer |
| |
| When calculating a pointer to the currently selected fw_cfg item, the |
| following is used: |
| |
| FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; |
| |
| When s->cur_entry is FW_CFG_INVALID, we are calculating the address of |
| a non-existent element in s->entries[arch][...], which is undefined. |
| |
| This patch ensures the resulting entry pointer is set to NULL whenever |
| s->cur_entry is FW_CFG_INVALID. |
| |
| Reported-by: Laszlo Ersek <lersek@redhat.com> |
| Reviewed-by: Laszlo Ersek <lersek@redhat.com> |
| Signed-off-by: Gabriel Somlo <somlo@cmu.edu> |
| Message-id: 1446733972-1602-5-git-send-email-somlo@cmu.edu |
| Cc: Marc MarĂ <markmb@redhat.com> |
| Signed-off-by: Gabriel Somlo <somlo@cmu.edu> |
| Reviewed-by: Laszlo Ersek <lersek@redhat.com> |
| Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> |
| |
| with added chunk for fw_cfg_write() that was removed in commit |
| 023e3148567ac898c7258138f8e86c3c2bb40d07 |
| and missing chunk for fw_cfg_dma_transfer that was added in commit |
| a4c0d1deb785611c96a455f65ec032976b00b36f. |
| |
| Reported-by: Donghai Zdh <donghai.zdh@alibaba-inc.com> |
| Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> |
| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| hw/nvram/fw_cfg.c | 12 ++++++++---- |
| 1 file changed, 8 insertions(+), 4 deletions(-) |
| |
| diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c |
| index b865c09..fcb3146 100644 |
| |
| |
| @@ -207,12 +207,15 @@ static void fw_cfg_reboot(FWCfgState *s) |
| static void fw_cfg_write(FWCfgState *s, uint8_t value) |
| { |
| int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); |
| - FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; |
| + FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL : |
| + &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; |
| |
| trace_fw_cfg_write(s, value); |
| |
| - if (s->cur_entry & FW_CFG_WRITE_CHANNEL && e->callback && |
| - s->cur_offset < e->len) { |
| + if (s->cur_entry & FW_CFG_WRITE_CHANNEL |
| + && e != NULL |
| + && e->callback |
| + && s->cur_offset < e->len) { |
| e->data[s->cur_offset++] = value; |
| if (s->cur_offset == e->len) { |
| e->callback(e->callback_opaque, e->data); |
| @@ -241,7 +244,8 @@ static int fw_cfg_select(FWCfgState *s, uint16_t key) |
| static uint8_t fw_cfg_read(FWCfgState *s) |
| { |
| int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); |
| - FWCfgEntry *e = &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; |
| + FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL : |
| + &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; |
| uint8_t ret; |
| |
| if (s->cur_entry == FW_CFG_INVALID || !e->data || s->cur_offset >= e->len) |
| -- |
| 1.8.3.1 |
| |