[PATCH] remoteproc: Use struct_size() helper

[PATCH] remoteproc: Use struct_size() helper

[Gustavo A. R. Silva]

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct resource_table {
	...
        u32 offset[0];
} __packed;

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

table->num * sizeof(table->offset[0]) + sizeof(struct resource_table)

with:

struct_size(table, offset, table->num)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/remoteproc/remoteproc_elf_loader.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
index 215a4400f21e..606aae166eba 100644
--- a/drivers/remoteproc/remoteproc_elf_loader.c
+++ b/drivers/remoteproc/remoteproc_elf_loader.c
@@ -247,8 +247,7 @@ find_table(struct device *dev, struct elf32_hdr *ehdr, size_t fw_size)
 		}
 
 		/* make sure the offsets array isn't truncated */
-		if (table->num * sizeof(table->offset[0]) +
-				sizeof(struct resource_table) > size) {
+		if (struct_size(table, offset, table->num) > size) {
 			dev_err(dev, "resource table incomplete\n");
 			return NULL;
 		}
-- 
2.21.0

Re: [PATCH] remoteproc: Use struct_size() helper

[Bjorn Andersson]

On Fri 07 Jun 11:53 PDT 2019, Gustavo A. R. Silva wrote:

> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
> 
> struct resource_table {
> 	...
>         u32 offset[0];
> } __packed;
> 
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
> 
> So, replace the following form:
> 
> table->num * sizeof(table->offset[0]) + sizeof(struct resource_table)
> 
> with:
> 
> struct_size(table, offset, table->num)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Looks good, applied

Thanks,
Bjorn

> ---
>  drivers/remoteproc/remoteproc_elf_loader.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
> index 215a4400f21e..606aae166eba 100644
> --- a/drivers/remoteproc/remoteproc_elf_loader.c
> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
> @@ -247,8 +247,7 @@ find_table(struct device *dev, struct elf32_hdr *ehdr, size_t fw_size)
>  		}
>  
>  		/* make sure the offsets array isn't truncated */
> -		if (table->num * sizeof(table->offset[0]) +
> -				sizeof(struct resource_table) > size) {
> +		if (struct_size(table, offset, table->num) > size) {
>  			dev_err(dev, "resource table incomplete\n");
>  			return NULL;
>  		}
> -- 
> 2.21.0
> 

[PATCH] remoteproc: use struct_size() helper

[Gustavo A. R. Silva]

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct fw_rsc_vdev {
	...
        struct fw_rsc_vdev_vring vring[0];
} __packed;

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*rsc) + rsc->num_of_vrings * sizeof(struct fw_rsc_vdev_vring)

with:

struct_size(rsc, vring, rsc->num_of_vrings)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/remoteproc/remoteproc_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 3c5fbbbfb0f1..d427b8208ad6 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -478,8 +478,8 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
 	char name[16];
 
 	/* make sure resource isn't truncated */
-	if (sizeof(*rsc) + rsc->num_of_vrings * sizeof(struct fw_rsc_vdev_vring)
-			+ rsc->config_len > avail) {
+	if (struct_size(rsc, vring, rsc->num_of_vrings) + rsc->config_len >
+			avail) {
 		dev_err(dev, "vdev rsc is truncated\n");
 		return -EINVAL;
 	}
-- 
2.23.0