On 2023-09-30 02:00:05-0300, Wedson Almeida Filho wrote:
> From: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>
>
> As it is currently declared, the xattr_handler structs are const but the
> array containing their pointers is not. This patch makes it so that fs
> modules can place them in .rodata, which makes it harder for
> accidental/malicious modifications at runtime.
You could also add an entry to scripts/const_structs.checkpatch to make
sure newly introduced usages of the struct are const.
Could be a single dedicated patch after this patch has been applied.
> Signed-off-by: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>
> ---
> fs/xattr.c | 6 +++---
> include/linux/fs.h | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xattr.c b/fs/xattr.c
> index e7bbb7f57557..1905f8ede13d 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -56,7 +56,7 @@ strcmp_prefix(const char *a, const char *a_prefix)
> static const struct xattr_handler *
> xattr_resolve_name(struct inode *inode, const char **name)
> {
> - const struct xattr_handler **handlers = inode->i_sb->s_xattr;
> + const struct xattr_handler * const *handlers = inode->i_sb->s_xattr;
> const struct xattr_handler *handler;
>
> if (!(inode->i_opflags & IOP_XATTR)) {
> @@ -162,7 +162,7 @@ xattr_permission(struct mnt_idmap *idmap, struct inode *inode,
> int
> xattr_supports_user_prefix(struct inode *inode)
> {
> - const struct xattr_handler **handlers = inode->i_sb->s_xattr;
> + const struct xattr_handler * const *handlers = inode->i_sb->s_xattr;
> const struct xattr_handler *handler;
>
> if (!(inode->i_opflags & IOP_XATTR)) {
> @@ -999,7 +999,7 @@ int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name)
> ssize_t
> generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
> {
> - const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
> + const struct xattr_handler *handler, * const *handlers = dentry->d_sb->s_xattr;
> ssize_t remaining_size = buffer_size;
> int err = 0;
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 562f2623c9c9..4d8003f48216 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1172,7 +1172,7 @@ struct super_block {
> #ifdef CONFIG_SECURITY
> void *s_security;
> #endif
> - const struct xattr_handler **s_xattr;
> + const struct xattr_handler * const *s_xattr;
> #ifdef CONFIG_FS_ENCRYPTION
> const struct fscrypt_operations *s_cop;
> struct fscrypt_keyring *s_master_keys; /* master crypto keys in use */
> --
> 2.34.1
>
