On Thu, Jun 19, 2014 at 7:49 AM, Heinrich Schuchardt <xypron.glpk@xxxxxx> wrote: > This updated patch also fixes out of bound access to b[]. > > In dib9000_risc_apb_access_write() an out of bound access to mb[]. > > The current test to avoid out of bound access to mb[] is insufficient. > For len = 19 non-existent mb[10] will be accessed. > > For odd values of len b[] is accessed out of bounds. > > For large values of len an of bound access to mb[] may occur in > dib9000_mbx_send_attr. > > Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx> > --- > drivers/media/dvb-frontends/dib9000.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/dvb-frontends/dib9000.c b/drivers/media/dvb-frontends/dib9000.c > index e540cfb..f75dec4 100644 > --- a/drivers/media/dvb-frontends/dib9000.c > +++ b/drivers/media/dvb-frontends/dib9000.c > @@ -1040,13 +1040,18 @@ static int dib9000_risc_apb_access_write(struct dib9000_state *state, u32 addres > if (address >= 1024 || !state->platform.risc.fw_is_running) > return -EINVAL; > > + if (len > 18) > + return -EINVAL; > + > /* dprintk( "APB access thru wr fw %d %x", address, attribute); */ > > - mb[0] = (unsigned short)address; > - for (i = 0; i < len && i < 20; i += 2) > - mb[1 + (i / 2)] = (b[i] << 8 | b[i + 1]); > + mb[0] = (u16)address; > + for (i = 0; i + 1 < len; i += 2) > + mb[1 + i / 2] = b[i] << 8 | b[i + 1]; > + if (len & 1) > + mb[1 + len / 2] = b[len - 1] << 8; > > - dib9000_mbx_send_attr(state, OUT_MSG_BRIDGE_APB_W, mb, 1 + len / 2, attribute); > + dib9000_mbx_send_attr(state, OUT_MSG_BRIDGE_APB_W, mb, (3 + len) / 2, attribute); > return dib9000_mbx_get_message_attr(state, IN_MSG_END_BRIDGE_APB_RW, mb, &s, attribute) == 1 ? 0 : -EINVAL; > } > > -- > 2.0.0 > That looks great, thanks! Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
