projects / packages / qemu.git / blame
| Commit | Line | Data |
|---|---|---|
| f0aafe84 ER |
1 | From e907746266721f305d67bc0718795fedee2e824c Mon Sep 17 00:00:00 2001 |
| 2 | From: Petr Matousek <pmatouse@redhat.com> | |
| 3 | Date: Wed, 6 May 2015 09:48:59 +0200 | |
| 4 | Subject: [PATCH] fdc: force the fifo access to be in bounds of the allocated buffer | |
| 5 | ||
| 6 | During processing of certain commands such as FD_CMD_READ_ID and | |
| 7 | FD_CMD_DRIVE_SPECIFICATION_COMMAND the fifo memory access could | |
| 8 | get out of bounds leading to memory corruption with values coming | |
| 9 | from the guest. | |
| 10 | ||
| 11 | Fix this by making sure that the index is always bounded by the | |
| 12 | allocated memory. | |
| 13 | ||
| 14 | This is CVE-2015-3456. | |
| 15 | ||
| 16 | Signed-off-by: Petr Matousek <pmatouse@redhat.com> | |
| 17 | Reviewed-by: John Snow <jsnow@redhat.com> | |
| 18 | Signed-off-by: John Snow <jsnow@redhat.com> | |
| 19 | --- | |
| 20 | hw/block/fdc.c | 17 +++++++++++------ | |
| 21 | 1 files changed, 11 insertions(+), 6 deletions(-) | |
| 22 | ||
| 23 | diff --git a/hw/block/fdc.c b/hw/block/fdc.c | |
| 24 | index f72a392..d8a8edd 100644 | |
| 25 | --- a/hw/block/fdc.c | |
| 26 | +++ b/hw/block/fdc.c | |
| 27 | @@ -1497,7 +1497,7 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl) | |
| 28 | { | |
| 29 | FDrive *cur_drv; | |
| 30 | uint32_t retval = 0; | |
| 31 | - int pos; | |
| 32 | + uint32_t pos; | |
| 33 | ||
| 34 | cur_drv = get_cur_drv(fdctrl); | |
| 35 | fdctrl->dsr &= ~FD_DSR_PWRDOWN; | |
| 36 | @@ -1506,8 +1506,8 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl) | |
| 37 | return 0; | |
| 38 | } | |
| 39 | pos = fdctrl->data_pos; | |
| 40 | + pos %= FD_SECTOR_LEN; | |
| 41 | if (fdctrl->msr & FD_MSR_NONDMA) { | |
| 42 | - pos %= FD_SECTOR_LEN; | |
| 43 | if (pos == 0) { | |
| 44 | if (fdctrl->data_pos != 0) | |
| 45 | if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv)) { | |
| 46 | @@ -1852,10 +1852,13 @@ static void fdctrl_handle_option(FDCtrl *fdctrl, int direction) | |
| 47 | static void fdctrl_handle_drive_specification_command(FDCtrl *fdctrl, int direction) | |
| 48 | { | |
| 49 | FDrive *cur_drv = get_cur_drv(fdctrl); | |
| 50 | + uint32_t pos; | |
| 51 | ||
| 52 | - if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x80) { | |
| 53 | + pos = fdctrl->data_pos - 1; | |
| 54 | + pos %= FD_SECTOR_LEN; | |
| 55 | + if (fdctrl->fifo[pos] & 0x80) { | |
| 56 | /* Command parameters done */ | |
| 57 | - if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x40) { | |
| 58 | + if (fdctrl->fifo[pos] & 0x40) { | |
| 59 | fdctrl->fifo[0] = fdctrl->fifo[1]; | |
| 60 | fdctrl->fifo[2] = 0; | |
| 61 | fdctrl->fifo[3] = 0; | |
| 62 | @@ -1955,7 +1958,7 @@ static uint8_t command_to_handler[256]; | |
| 63 | static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value) | |
| 64 | { | |
| 65 | FDrive *cur_drv; | |
| 66 | - int pos; | |
| 67 | + uint32_t pos; | |
| 68 | ||
| 69 | /* Reset mode */ | |
| 70 | if (!(fdctrl->dor & FD_DOR_nRESET)) { | |
| 71 | @@ -2004,7 +2007,9 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value) | |
| 72 | } | |
| 73 | ||
| 74 | FLOPPY_DPRINTF("%s: %02x\n", __func__, value); | |
| 75 | - fdctrl->fifo[fdctrl->data_pos++] = value; | |
| 76 | + pos = fdctrl->data_pos++; | |
| 77 | + pos %= FD_SECTOR_LEN; | |
| 78 | + fdctrl->fifo[pos] = value; | |
| 79 | if (fdctrl->data_pos == fdctrl->data_len) { | |
| 80 | /* We now have all parameters | |
| 81 | * and will be able to treat the command | |
| 82 | -- | |
| 83 | 1.7.0.4 | |
| 84 |