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module: Refactor section attr into bin attribute
In order to gain access to the open file's f_cred for kallsym visibility permission checks, refactor the module section attributes to use the bin_attribute instead of attribute interface. Additionally removes the redundant "name" struct member. Cc: stable@vger.kernel.org Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Tested-by: Jessica Yu <jeyu@kernel.org> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org>
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160251842c
commit
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1 changed files with 24 additions and 21 deletions
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@ -1510,8 +1510,7 @@ static inline bool sect_empty(const Elf_Shdr *sect)
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}
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struct module_sect_attr {
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struct module_attribute mattr;
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char *name;
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struct bin_attribute battr;
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unsigned long address;
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};
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@ -1521,11 +1520,16 @@ struct module_sect_attrs {
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struct module_sect_attr attrs[];
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};
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static ssize_t module_sect_show(struct module_attribute *mattr,
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struct module_kobject *mk, char *buf)
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static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
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struct bin_attribute *battr,
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char *buf, loff_t pos, size_t count)
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{
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struct module_sect_attr *sattr =
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container_of(mattr, struct module_sect_attr, mattr);
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container_of(battr, struct module_sect_attr, battr);
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if (pos != 0)
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return -EINVAL;
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return sprintf(buf, "0x%px\n", kptr_restrict < 2 ?
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(void *)sattr->address : NULL);
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}
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@ -1535,7 +1539,7 @@ static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
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unsigned int section;
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for (section = 0; section < sect_attrs->nsections; section++)
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kfree(sect_attrs->attrs[section].name);
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kfree(sect_attrs->attrs[section].battr.attr.name);
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kfree(sect_attrs);
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}
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@ -1544,42 +1548,41 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info)
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unsigned int nloaded = 0, i, size[2];
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struct module_sect_attrs *sect_attrs;
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struct module_sect_attr *sattr;
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struct attribute **gattr;
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struct bin_attribute **gattr;
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/* Count loaded sections and allocate structures */
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for (i = 0; i < info->hdr->e_shnum; i++)
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if (!sect_empty(&info->sechdrs[i]))
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nloaded++;
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size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),
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sizeof(sect_attrs->grp.attrs[0]));
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size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
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sizeof(sect_attrs->grp.bin_attrs[0]));
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size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);
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sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
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if (sect_attrs == NULL)
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return;
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/* Setup section attributes. */
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sect_attrs->grp.name = "sections";
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sect_attrs->grp.attrs = (void *)sect_attrs + size[0];
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sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0];
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sect_attrs->nsections = 0;
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sattr = §_attrs->attrs[0];
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gattr = §_attrs->grp.attrs[0];
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gattr = §_attrs->grp.bin_attrs[0];
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for (i = 0; i < info->hdr->e_shnum; i++) {
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Elf_Shdr *sec = &info->sechdrs[i];
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if (sect_empty(sec))
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continue;
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sysfs_bin_attr_init(&sattr->battr);
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sattr->address = sec->sh_addr;
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sattr->name = kstrdup(info->secstrings + sec->sh_name,
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GFP_KERNEL);
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if (sattr->name == NULL)
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sattr->battr.attr.name =
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kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
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if (sattr->battr.attr.name == NULL)
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goto out;
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sect_attrs->nsections++;
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sysfs_attr_init(&sattr->mattr.attr);
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sattr->mattr.show = module_sect_show;
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sattr->mattr.store = NULL;
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sattr->mattr.attr.name = sattr->name;
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sattr->mattr.attr.mode = S_IRUSR;
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*(gattr++) = &(sattr++)->mattr.attr;
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sattr->battr.read = module_sect_read;
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sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4);
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sattr->battr.attr.mode = 0400;
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*(gattr++) = &(sattr++)->battr;
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}
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*gattr = NULL;
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@ -1669,7 +1672,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info)
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continue;
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if (info->sechdrs[i].sh_type == SHT_NOTE) {
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sysfs_bin_attr_init(nattr);
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nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
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nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;
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nattr->attr.mode = S_IRUGO;
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nattr->size = info->sechdrs[i].sh_size;
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nattr->private = (void *) info->sechdrs[i].sh_addr;
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