audit: Use struct_size() helper in alloc_chunk

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 audit_chunk {
        ...
        struct node {
                struct list_head list;
                struct audit_tree *owner;
                unsigned index;         /* index; upper bit indicates 'will prune' */
        } owners[];
};

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:

offsetof(struct audit_chunk, owners) + count * sizeof(struct node);

with:

struct_size(chunk, owners, count)

This code was detected with the help of Coccinelle.

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
 kernel/audit_tree.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Quoted 5 lines

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
 kernel/audit_tree.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Thanks, this looks reasonable to me, but it came in too late for the v5.8 merge window (I dislike taking changes past -rc5/6 unless

critical). Once the merge window closes I'll merge this into audit/next.

Quoted 22 lines · 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 audit_chunk {
        ...
        struct node {
                struct list_head list;
                struct audit_tree *owner;
                unsigned index;         /* index; upper bit indicates 'will prune' */
        } owners[];
};

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:

offsetof(struct audit_chunk, owners) + count * sizeof(struct node);

with:

Quoted 8 lines

struct_size(chunk, owners, count)

This code was detected with the help of Coccinelle.

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
 kernel/audit_tree.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Thanks, this looks reasonable to me, but it came in too late for the v5.8 merge window (I dislike taking changes past -rc5/6 unless critical). Once the merge window closes I'll merge this into audit/next.