Commit ed66f991 authored by Kees Cook's avatar Kees Cook

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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: default avatarJessica Yu <jeyu@kernel.org>
Acked-by: default avatarJessica Yu <jeyu@kernel.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 16025184
...@@ -1510,8 +1510,7 @@ static inline bool sect_empty(const Elf_Shdr *sect) ...@@ -1510,8 +1510,7 @@ static inline bool sect_empty(const Elf_Shdr *sect)
} }
struct module_sect_attr { struct module_sect_attr {
struct module_attribute mattr; struct bin_attribute battr;
char *name;
unsigned long address; unsigned long address;
}; };
...@@ -1521,11 +1520,16 @@ struct module_sect_attrs { ...@@ -1521,11 +1520,16 @@ struct module_sect_attrs {
struct module_sect_attr attrs[]; struct module_sect_attr attrs[];
}; };
static ssize_t module_sect_show(struct module_attribute *mattr, static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
struct module_kobject *mk, char *buf) struct bin_attribute *battr,
char *buf, loff_t pos, size_t count)
{ {
struct module_sect_attr *sattr = struct module_sect_attr *sattr =
container_of(mattr, struct module_sect_attr, mattr); container_of(battr, struct module_sect_attr, battr);
if (pos != 0)
return -EINVAL;
return sprintf(buf, "0x%px\n", kptr_restrict < 2 ? return sprintf(buf, "0x%px\n", kptr_restrict < 2 ?
(void *)sattr->address : NULL); (void *)sattr->address : NULL);
} }
...@@ -1535,7 +1539,7 @@ static void free_sect_attrs(struct module_sect_attrs *sect_attrs) ...@@ -1535,7 +1539,7 @@ static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
unsigned int section; unsigned int section;
for (section = 0; section < sect_attrs->nsections; section++) for (section = 0; section < sect_attrs->nsections; section++)
kfree(sect_attrs->attrs[section].name); kfree(sect_attrs->attrs[section].battr.attr.name);
kfree(sect_attrs); kfree(sect_attrs);
} }
...@@ -1544,42 +1548,41 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info) ...@@ -1544,42 +1548,41 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info)
unsigned int nloaded = 0, i, size[2]; unsigned int nloaded = 0, i, size[2];
struct module_sect_attrs *sect_attrs; struct module_sect_attrs *sect_attrs;
struct module_sect_attr *sattr; struct module_sect_attr *sattr;
struct attribute **gattr; struct bin_attribute **gattr;
/* Count loaded sections and allocate structures */ /* Count loaded sections and allocate structures */
for (i = 0; i < info->hdr->e_shnum; i++) for (i = 0; i < info->hdr->e_shnum; i++)
if (!sect_empty(&info->sechdrs[i])) if (!sect_empty(&info->sechdrs[i]))
nloaded++; nloaded++;
size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded), size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),
sizeof(sect_attrs->grp.attrs[0])); sizeof(sect_attrs->grp.bin_attrs[0]));
size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]); size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);
sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL); sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
if (sect_attrs == NULL) if (sect_attrs == NULL)
return; return;
/* Setup section attributes. */ /* Setup section attributes. */
sect_attrs->grp.name = "sections"; sect_attrs->grp.name = "sections";
sect_attrs->grp.attrs = (void *)sect_attrs + size[0]; sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0];
sect_attrs->nsections = 0; sect_attrs->nsections = 0;
sattr = &sect_attrs->attrs[0]; sattr = &sect_attrs->attrs[0];
gattr = &sect_attrs->grp.attrs[0]; gattr = &sect_attrs->grp.bin_attrs[0];
for (i = 0; i < info->hdr->e_shnum; i++) { for (i = 0; i < info->hdr->e_shnum; i++) {
Elf_Shdr *sec = &info->sechdrs[i]; Elf_Shdr *sec = &info->sechdrs[i];
if (sect_empty(sec)) if (sect_empty(sec))
continue; continue;
sysfs_bin_attr_init(&sattr->battr);
sattr->address = sec->sh_addr; sattr->address = sec->sh_addr;
sattr->name = kstrdup(info->secstrings + sec->sh_name, sattr->battr.attr.name =
GFP_KERNEL); kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
if (sattr->name == NULL) if (sattr->battr.attr.name == NULL)
goto out; goto out;
sect_attrs->nsections++; sect_attrs->nsections++;
sysfs_attr_init(&sattr->mattr.attr); sattr->battr.read = module_sect_read;
sattr->mattr.show = module_sect_show; sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4);
sattr->mattr.store = NULL; sattr->battr.attr.mode = 0400;
sattr->mattr.attr.name = sattr->name; *(gattr++) = &(sattr++)->battr;
sattr->mattr.attr.mode = S_IRUSR;
*(gattr++) = &(sattr++)->mattr.attr;
} }
*gattr = NULL; *gattr = NULL;
...@@ -1669,7 +1672,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info) ...@@ -1669,7 +1672,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info)
continue; continue;
if (info->sechdrs[i].sh_type == SHT_NOTE) { if (info->sechdrs[i].sh_type == SHT_NOTE) {
sysfs_bin_attr_init(nattr); sysfs_bin_attr_init(nattr);
nattr->attr.name = mod->sect_attrs->attrs[loaded].name; nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;
nattr->attr.mode = S_IRUGO; nattr->attr.mode = S_IRUGO;
nattr->size = info->sechdrs[i].sh_size; nattr->size = info->sechdrs[i].sh_size;
nattr->private = (void *) info->sechdrs[i].sh_addr; nattr->private = (void *) info->sechdrs[i].sh_addr;
......
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