d40_validate_conf() checks the raw dev_type against num_log_chans, but d40_allocate_channel() derives the lookup_log_chans index as either 2 * dev_type or 2 * dev_type + 1.
Validate the dev_type against the derived logical channel index limit so channel allocation cannot write past lookup_log_chans. Reported-by: [email protected] Closes: https://lore.kernel.org/dmaengine/[email protected]/ Assisted-by: Codex:gpt-5-5 Signed-off-by: Linus Walleij <[email protected]> --- drivers/dma/ste_dma40.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c index 4e840846466b..7c777e410c10 100644 --- a/drivers/dma/ste_dma40.c +++ b/drivers/dma/ste_dma40.c @@ -1737,15 +1737,26 @@ static int d40_validate_conf(struct d40_chan *d40c, { int res = 0; bool is_log = conf->mode == STEDMA40_MODE_LOGICAL; + bool invalid_dev_type = conf->dev_type < 0; if (!conf->dir) { chan_err(d40c, "Invalid direction.\n"); res = -EINVAL; } - if ((is_log && conf->dev_type > d40c->base->num_log_chans) || - (!is_log && conf->dev_type > d40c->base->num_phy_chans) || - (conf->dev_type < 0)) { + if (!invalid_dev_type && is_log) { + int max_dev_type; + + if (conf->dir == DMA_DEV_TO_MEM) + max_dev_type = DIV_ROUND_UP(d40c->base->num_log_chans, 2); + else + max_dev_type = d40c->base->num_log_chans / 2; + + invalid_dev_type = conf->dev_type >= max_dev_type; + } + + if (invalid_dev_type || + (!is_log && conf->dev_type > d40c->base->num_phy_chans)) { chan_err(d40c, "Invalid device type (%d)\n", conf->dev_type); res = -EINVAL; } -- 2.55.0
