Commit 10b465aa authored by Ben Hutchings's avatar Ben Hutchings Committed by Linus Torvalds

modules: Skip empty sections when exporting section notes

Commit 35dead42 "modules: don't export section names of empty sections
via sysfs" changed the set of sections that have attributes, but did
not change the iteration over these attributes in add_notes_attrs().
This can lead to add_notes_attrs() creating attributes with the wrong
names or with null name pointers.

Introduce a sect_empty() function and use it in both add_sect_attrs()
and add_notes_attrs().
Reported-by: default avatarMartin Michlmayr <tbm@cyrius.com>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Tested-by: default avatarMartin Michlmayr <tbm@cyrius.com>
Cc: stable@kernel.org
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 74d2e4f8
...@@ -1010,6 +1010,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs, ...@@ -1010,6 +1010,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
* J. Corbet <corbet@lwn.net> * J. Corbet <corbet@lwn.net>
*/ */
#if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS) #if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS)
static inline bool sect_empty(const Elf_Shdr *sect)
{
return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
}
struct module_sect_attr struct module_sect_attr
{ {
struct module_attribute mattr; struct module_attribute mattr;
...@@ -1051,8 +1057,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, ...@@ -1051,8 +1057,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
/* Count loaded sections and allocate structures */ /* Count loaded sections and allocate structures */
for (i = 0; i < nsect; i++) for (i = 0; i < nsect; i++)
if (sechdrs[i].sh_flags & SHF_ALLOC if (!sect_empty(&sechdrs[i]))
&& sechdrs[i].sh_size)
nloaded++; nloaded++;
size[0] = ALIGN(sizeof(*sect_attrs) size[0] = ALIGN(sizeof(*sect_attrs)
+ nloaded * sizeof(sect_attrs->attrs[0]), + nloaded * sizeof(sect_attrs->attrs[0]),
...@@ -1070,9 +1075,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, ...@@ -1070,9 +1075,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect,
sattr = &sect_attrs->attrs[0]; sattr = &sect_attrs->attrs[0];
gattr = &sect_attrs->grp.attrs[0]; gattr = &sect_attrs->grp.attrs[0];
for (i = 0; i < nsect; i++) { for (i = 0; i < nsect; i++) {
if (! (sechdrs[i].sh_flags & SHF_ALLOC)) if (sect_empty(&sechdrs[i]))
continue;
if (!sechdrs[i].sh_size)
continue; continue;
sattr->address = sechdrs[i].sh_addr; sattr->address = sechdrs[i].sh_addr;
sattr->name = kstrdup(secstrings + sechdrs[i].sh_name, sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
...@@ -1156,7 +1159,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, ...@@ -1156,7 +1159,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
/* Count notes sections and allocate structures. */ /* Count notes sections and allocate structures. */
notes = 0; notes = 0;
for (i = 0; i < nsect; i++) for (i = 0; i < nsect; i++)
if ((sechdrs[i].sh_flags & SHF_ALLOC) && if (!sect_empty(&sechdrs[i]) &&
(sechdrs[i].sh_type == SHT_NOTE)) (sechdrs[i].sh_type == SHT_NOTE))
++notes; ++notes;
...@@ -1172,7 +1175,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, ...@@ -1172,7 +1175,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect,
notes_attrs->notes = notes; notes_attrs->notes = notes;
nattr = &notes_attrs->attrs[0]; nattr = &notes_attrs->attrs[0];
for (loaded = i = 0; i < nsect; ++i) { for (loaded = i = 0; i < nsect; ++i) {
if (!(sechdrs[i].sh_flags & SHF_ALLOC)) if (sect_empty(&sechdrs[i]))
continue; continue;
if (sechdrs[i].sh_type == SHT_NOTE) { if (sechdrs[i].sh_type == SHT_NOTE) {
nattr->attr.name = mod->sect_attrs->attrs[loaded].name; nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
......
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