On Mon, Nov 15, 2021 at 09:34:54PM +0100, Marijn Suijten wrote: > When not specifying num-strings in the DT the default is used, but +1 is > added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead > of 3 and 4 respectively, causing out-of-bounds reads and register > read/writes. This +1 exists for a deficiency in the DT parsing code, > and is simply omitted entirely - solving this oob issue - by parsing the > property separately much like qcom,enabled-strings. > > This also enables more stringent checks on the maximum value when > qcom,enabled-strings is provided in the DT, by parsing num-strings after > enabled-strings to allow it to check against (and in a subsequent patch > override) the length of enabled-strings: it is invalid to set > num-strings higher than that. > The DT currently utilizes it to get around an incorrect fixed read of > four elements from that array (has been addressed in a prior patch) by > setting a lower num-strings where desired. > > Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") > Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx> > Reviewed-By: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx> Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx> Daniel.