diff options
| author | Petr Matousek <pmatouse@redhat.com> | 2015-05-06 09:48:59 +0200 |
|---|---|---|
| committer | David 'Digit' Turner <digit@google.com> | 2015-05-18 09:19:58 +0200 |
| commit | 3a1d5bcfef75950af05ccf969f44738fadc6a60f (patch) | |
| tree | ed034dee07dc0041d43b41a2badce1ccc61fd815 | |
| parent | bdc770594c8ca4a944fb79a2e6fdf2681890a38d (diff) | |
| download | qemu-android-3a1d5bcfef75950af05ccf969f44738fadc6a60f.tar.gz | |
Fix VENOM vulnerability for Intel-based systems.
This is a back-port of the upstream fix to the VENOM security
vulnerability, that affects the floppy disk virtual device
implementation.
Upstream origin:
http://git.qemu.org/?p=qemu.git;a=commitdiff;h=e907746266721f305d67bc0718795fedee2e824c
Upstream commit message:
fdc: force the fifo access to be in bounds of the allocated buffer
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 <pmatouse@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
BUG=21251683
Change-Id: I46c0908fa6ece61f84879a7cf8e60fa45548f7d0
| -rw-r--r-- | hw/block/fdc.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/hw/block/fdc.c b/hw/block/fdc.c index 739a03ed58..1168e8c36f 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 |