[PATCH] mmc: sunxi: Prevent against null dereference for vmmc
From: Maxime Ripard <hidden>
Date: 2016-10-19 15:04:56
Also in:
linux-mmc, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, the rest · Maintainers:
Ulf Hansson, Linus Torvalds
VMMC is an optional regulator, which means that mmc_regulator_get_supply will only return an error in case of a deferred probe, but not when the regulator is not set in the DT. However, the sunxi driver assumes that VMMC is always there, and doesn't check the value of the regulator pointer before using it, which obviously leads to a (close to) null pointer dereference. Add proper checks to prevent that. Signed-off-by: Maxime Ripard <redacted> --- drivers/mmc/host/sunxi-mmc.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index c0a5c676d0e8..45a051e7d650 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c@@ -822,10 +822,16 @@ static void sunxi_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) break; case MMC_POWER_UP: - host->ferror = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, - ios->vdd); - if (host->ferror) - return; + if (!IS_ERR(mmc->supply.vmmc)) { + host->ferror = mmc_regulator_set_ocr(mmc, + mmc->supply.vmmc, + ios->vdd); + if (host->ferror) { + dev_err(mmc_dev(mmc), + "failed to enable vmmc\n"); + return; + } + } if (!IS_ERR(mmc->supply.vqmmc)) { host->ferror = regulator_enable(mmc->supply.vqmmc);
@@ -847,7 +853,9 @@ static void sunxi_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) case MMC_POWER_OFF: dev_dbg(mmc_dev(mmc), "power off!\n"); sunxi_mmc_reset_host(host); - mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0); + if (!IS_ERR(mmc->supply.vmmc)) + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0); + if (!IS_ERR(mmc->supply.vqmmc) && host->vqmmc_enabled) regulator_disable(mmc->supply.vqmmc); host->vqmmc_enabled = false;
--
2.9.3