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authorNicholas Johnson <nicholas.johnson-opensource@outlook.com.au>2020-03-10 16:22:52 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-03-19 09:41:03 +0300
commit3c91ef69a3e94f78546b246225ed573fbf1735b4 (patch)
tree3251acb10ce8c6a59de3426fa5810b002a730114 /drivers/nvmem
parent061a320b32d47438d64d64b412c0ea2c323a1470 (diff)
downloadlinux-3c91ef69a3e94f78546b246225ed573fbf1735b4.tar.xz
nvmem: check for NULL reg_read and reg_write before dereferencing
Return -EPERM if reg_read is NULL in bin_attr_nvmem_read() or if reg_write is NULL in bin_attr_nvmem_write(). This prevents NULL dereferences such as the one described in 03cd45d2e219 ("thunderbolt: Prevent crash if non-active NVMem file is read") Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Cc: stable <stable@vger.kernel.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200310132257.23358-10-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/nvmem')
-rw-r--r--drivers/nvmem/nvmem-sysfs.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c
index 9e0c429cd08a..8759c4470012 100644
--- a/drivers/nvmem/nvmem-sysfs.c
+++ b/drivers/nvmem/nvmem-sysfs.c
@@ -56,6 +56,9 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
count = round_down(count, nvmem->word_size);
+ if (!nvmem->reg_read)
+ return -EPERM;
+
rc = nvmem->reg_read(nvmem->priv, pos, buf, count);
if (rc)
@@ -90,6 +93,9 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
count = round_down(count, nvmem->word_size);
+ if (!nvmem->reg_write)
+ return -EPERM;
+
rc = nvmem->reg_write(nvmem->priv, pos, buf, count);
if (rc)