From bba3d2daa8a9bc888902275401f15ef48fcdd378 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Mon, 31 Dec 2018 00:49:36 +0100 Subject: rtc: nvmem: fix possible use after free In cas of probe failure, devres may free the memory allocated for rtc->nvram before devm_rtc_release_device() is called. This leads to rtc_nvram_unregister using it after being freed which may lead to a crash. This has been shown to happen after commit 461e557b9727 ("rtc: nvmem: use devm_nvmem_register()") Reported-by: kernel test robot Signed-off-by: Alexandre Belloni --- drivers/rtc/nvmem.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c index ebdfe8e3a1a0..dce518d5e50e 100644 --- a/drivers/rtc/nvmem.c +++ b/drivers/rtc/nvmem.c @@ -12,6 +12,7 @@ #include #include #include +#include #include /* @@ -45,9 +46,7 @@ static int rtc_nvram_register(struct rtc_device *rtc, { int err; - rtc->nvram = devm_kzalloc(rtc->dev.parent, - sizeof(struct bin_attribute), - GFP_KERNEL); + rtc->nvram = kzalloc(sizeof(struct bin_attribute), GFP_KERNEL); if (!rtc->nvram) return -ENOMEM; @@ -64,7 +63,7 @@ static int rtc_nvram_register(struct rtc_device *rtc, err = sysfs_create_bin_file(&rtc->dev.parent->kobj, rtc->nvram); if (err) { - devm_kfree(rtc->dev.parent, rtc->nvram); + kfree(rtc->nvram); rtc->nvram = NULL; } @@ -74,6 +73,8 @@ static int rtc_nvram_register(struct rtc_device *rtc, static void rtc_nvram_unregister(struct rtc_device *rtc) { sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram); + kfree(rtc->nvram); + rtc->nvram = NULL; } /* -- cgit 1.4.1