From 835667157461e65399654cb726bad2075ddab26c Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Wed, 22 Jul 2020 11:06:54 +0100 Subject: [PATCH] nvmem: Enforce nvmem stride in the sysfs interface The 'struct nvmem_config' has a stride attribute that specifies the needed alignment for accesses into the nvmem. This is used in nvmem_cell_info_to_nvmem_cell() but not in the sysfs read/write functions. If the alignment is important in one place it's important everywhere, so let's add enforcement. For now we'll consider it totally invalid to access with the wrong alignment. We could relax this in the read case where we could just read some extra bytes and throw them away. Relaxing it in the write case seems harder (and less safe?) since we'd have to read some data first and then write it back. To keep it symmetric we'll just disallow it in both cases. Reported-by: Ravi Kumar Bokka Signed-off-by: Douglas Anderson Reviewed-by: Ravi Kumar Bokka Tested-by: Ravi Kumar Bokka Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20200722100705.7772-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 927eb5f6003f..fc480d636be2 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -135,6 +135,9 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj, if (pos >= nvmem->size) return 0; + if (!IS_ALIGNED(pos, nvmem->stride)) + return -EINVAL; + if (count < nvmem->word_size) return -EINVAL; @@ -172,6 +175,9 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, if (pos >= nvmem->size) return -EFBIG; + if (!IS_ALIGNED(pos, nvmem->stride)) + return -EINVAL; + if (count < nvmem->word_size) return -EINVAL;