diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2026-02-05 13:39:49 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 14:39:21 +0200 |
| commit | 3fb43a7a5b44713f892c58ead2e5f3a1bc9f4ee7 (patch) | |
| tree | db1255f645437d0e0109de3ea84e9fdb4f5195f4 | |
| parent | 101ab946b79ad83b36d5cfd47de587492a80acf0 (diff) | |
comedi: me4000: Fix potential overrun of firmware buffer
`me4000_xilinx_download()` loads the firmware that was requested by
`request_firmware()`. It is possible for it to overrun the source
buffer because it blindly trusts the file format. It reads a data
stream length from the first 4 bytes into variable `file_length` and
reads the data stream contents of length `file_length` from offset 16
onwards.
Add a test to ensure that the supplied firmware is long enough to
contain the header and the data stream. On failure, log an error and
return `-EINVAL`.
Note: The firmware loading was totally broken before commit ac584af59945
("staging: comedi: me4000: fix firmware downloading"), but that is the
most sensible target for this fix.
Fixes: ac584af59945 ("staging: comedi: me4000: fix firmware downloading")
Cc: stable <stable@kernel.org>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260205133949.71722-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/comedi/drivers/me4000.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/comedi/drivers/me4000.c b/drivers/comedi/drivers/me4000.c index 7dd3a0071863..effe9fdbbafe 100644 --- a/drivers/comedi/drivers/me4000.c +++ b/drivers/comedi/drivers/me4000.c @@ -315,6 +315,18 @@ static int me4000_xilinx_download(struct comedi_device *dev, unsigned int val; unsigned int i; + /* Get data stream length from header. */ + if (size >= 4) { + file_length = (((unsigned int)data[0] & 0xff) << 24) + + (((unsigned int)data[1] & 0xff) << 16) + + (((unsigned int)data[2] & 0xff) << 8) + + ((unsigned int)data[3] & 0xff); + } + if (size < 16 || file_length > size - 16) { + dev_err(dev->class_dev, "Firmware length inconsistency\n"); + return -EINVAL; + } + if (!xilinx_iobase) return -ENODEV; @@ -346,10 +358,6 @@ static int me4000_xilinx_download(struct comedi_device *dev, outl(val, devpriv->plx_regbase + PLX9052_CNTRL); /* Download Xilinx firmware */ - file_length = (((unsigned int)data[0] & 0xff) << 24) + - (((unsigned int)data[1] & 0xff) << 16) + - (((unsigned int)data[2] & 0xff) << 8) + - ((unsigned int)data[3] & 0xff); usleep_range(10, 1000); for (i = 0; i < file_length; i++) { |