| Message ID | 20160130144432.GF3462@mwanda (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 30/01/16 16:44, Dan Carpenter wrote: > par->metromem_cmd->args[] is an array of 31 elements of size u16. Here > we have initialized the first "i" elements and want to set the rest to > zero. > > The issue here is that ARRAY_SIZE(par->metromem_cmd->args) is 31 and not > 32 as in the original code. It means that we set ->csum to zero, but > that is harmless because we immediately set it to the correct value on > the next line. > > Still, the buffer overflow upsets static checkers so let's correct the > math. Thanks, queued for 4.6. Tomi
diff --git a/drivers/video/fbdev/metronomefb.c b/drivers/video/fbdev/metronomefb.c index ad04a01..abb6bbf 100644 --- a/drivers/video/fbdev/metronomefb.c +++ b/drivers/video/fbdev/metronomefb.c @@ -354,7 +354,8 @@ static int metronome_powerup_cmd(struct metronomefb_par *par) } /* the rest are 0 */ - memset((u8 *) (par->metromem_cmd->args + i), 0, (32-i)*2); + memset(&par->metromem_cmd->args[i], 0, + (ARRAY_SIZE(par->metromem_cmd->args) - i) * 2); par->metromem_cmd->csum = cs; @@ -376,7 +377,8 @@ static int metronome_config_cmd(struct metronomefb_par *par) memcpy(par->metromem_cmd->args, epd_frame_table[par->dt].config, sizeof(epd_frame_table[par->dt].config)); /* the rest are 0 */ - memset((u8 *) (par->metromem_cmd->args + 4), 0, (32-4)*2); + memset(&par->metromem_cmd->args[4], 0, + (ARRAY_SIZE(par->metromem_cmd->args) - 4) * 2); par->metromem_cmd->csum = 0xCC10; par->metromem_cmd->csum += calc_img_cksum(par->metromem_cmd->args, 4);
par->metromem_cmd->args[] is an array of 31 elements of size u16. Here we have initialized the first "i" elements and want to set the rest to zero. The issue here is that ARRAY_SIZE(par->metromem_cmd->args) is 31 and not 32 as in the original code. It means that we set ->csum to zero, but that is harmless because we immediately set it to the correct value on the next line. Still, the buffer overflow upsets static checkers so let's correct the math. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html