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[Qemu-stable] [PATCH 11/53] fdc: force the fifo access to be in bounds o
From: |
Michael Roth |
Subject: |
[Qemu-stable] [PATCH 11/53] fdc: force the fifo access to be in bounds of the allocated buffer |
Date: |
Thu, 30 Jul 2015 06:32:26 -0500 |
From: Petr Matousek <address@hidden>
During processing of certain commands such as FD_CMD_READ_ID and
FD_CMD_DRIVE_SPECIFICATION_COMMAND the fifo memory access could
get out of bounds leading to memory corruption with values coming
from the guest.
Fix this by making sure that the index is always bounded by the
allocated memory.
This is CVE-2015-3456.
Signed-off-by: Petr Matousek <address@hidden>
Reviewed-by: John Snow <address@hidden>
Signed-off-by: John Snow <address@hidden>
(cherry picked from commit e907746266721f305d67bc0718795fedee2e824c)
Signed-off-by: Michael Roth <address@hidden>
---
hw/block/fdc.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 2bf87c9..a9de4ab 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -1512,7 +1512,7 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl)
{
FDrive *cur_drv;
uint32_t retval = 0;
- int pos;
+ uint32_t pos;
cur_drv = get_cur_drv(fdctrl);
fdctrl->dsr &= ~FD_DSR_PWRDOWN;
@@ -1521,8 +1521,8 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl)
return 0;
}
pos = fdctrl->data_pos;
+ pos %= FD_SECTOR_LEN;
if (fdctrl->msr & FD_MSR_NONDMA) {
- pos %= FD_SECTOR_LEN;
if (pos == 0) {
if (fdctrl->data_pos != 0)
if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv)) {
@@ -1867,10 +1867,13 @@ static void fdctrl_handle_option(FDCtrl *fdctrl, int
direction)
static void fdctrl_handle_drive_specification_command(FDCtrl *fdctrl, int
direction)
{
FDrive *cur_drv = get_cur_drv(fdctrl);
+ uint32_t pos;
- if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x80) {
+ pos = fdctrl->data_pos - 1;
+ pos %= FD_SECTOR_LEN;
+ if (fdctrl->fifo[pos] & 0x80) {
/* Command parameters done */
- if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x40) {
+ if (fdctrl->fifo[pos] & 0x40) {
fdctrl->fifo[0] = fdctrl->fifo[1];
fdctrl->fifo[2] = 0;
fdctrl->fifo[3] = 0;
@@ -1970,7 +1973,7 @@ static uint8_t command_to_handler[256];
static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value)
{
FDrive *cur_drv;
- int pos;
+ uint32_t pos;
/* Reset mode */
if (!(fdctrl->dor & FD_DOR_nRESET)) {
@@ -2019,7 +2022,9 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t
value)
}
FLOPPY_DPRINTF("%s: %02x\n", __func__, value);
- fdctrl->fifo[fdctrl->data_pos++] = value;
+ pos = fdctrl->data_pos++;
+ pos %= FD_SECTOR_LEN;
+ fdctrl->fifo[pos] = value;
if (fdctrl->data_pos == fdctrl->data_len) {
/* We now have all parameters
* and will be able to treat the command
--
1.9.1
- [Qemu-stable] Patch Round-up for stable 2.3.1, freeze on 2015-08-06, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 09/53] virtio-net: fix the upper bound when trying to delete queues, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 10/53] target-arm: Avoid buffer overrun on UNPREDICTABLE ldrd/strd, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 11/53] fdc: force the fifo access to be in bounds of the allocated buffer,
Michael Roth <=
- [Qemu-stable] [PATCH 12/53] Revert "block: Fix unaligned zero write", Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 13/53] block: Fix NULL deference for unaligned write if qiov is NULL, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 14/53] qemu-iotests: Test unaligned sub-block zero write, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 15/53] hw/acpi/aml-build: Fix memory leak, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 18/53] kbd: add brazil kbd keys to x11 evdev map, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 20/53] iotests: qcow2 COW with minimal L2 cache size, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 16/53] qga/commands-posix: Fix bug in guest-fstrim, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 01/53] bt-sdp: fix broken uuids power-of-2 calculation, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 17/53] kbd: add brazil kbd keys to qemu, Michael Roth, 2015/07/30
- [Qemu-stable] [PATCH 21/53] vmdk: Fix index_in_cluster calculation in vmdk_co_get_block_status, Michael Roth, 2015/07/30