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

kernel/module.c

+10 −7
Original line number Diff line number Diff line
@@ -1010,6 +1010,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs, 
 * J. Corbet <corbet@lwn.net>

 */

#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_attribute mattr;
@@ -1051,8 +1057,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, 


	/* Count loaded sections and allocate structures */

	for (i = 0; i < nsect; i++)

		if (sechdrs[i].sh_flags & SHF_ALLOC

		    && sechdrs[i].sh_size)

		if (!sect_empty(&sechdrs[i]))

			nloaded++;

	size[0] = ALIGN(sizeof(*sect_attrs)

			+ nloaded * sizeof(sect_attrs->attrs[0]),
@@ -1070,9 +1075,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, 
	sattr = &sect_attrs->attrs[0];

	gattr = &sect_attrs->grp.attrs[0];

	for (i = 0; i < nsect; i++) {

		if (! (sechdrs[i].sh_flags & SHF_ALLOC))

			continue;

		if (!sechdrs[i].sh_size)

		if (sect_empty(&sechdrs[i]))

			continue;

		sattr->address = sechdrs[i].sh_addr;

		sattr->name = kstrdup(secstrings + sechdrs[i].sh_name,
@@ -1156,7 +1159,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, 
	/* Count notes sections and allocate structures.  */

	notes = 0;

	for (i = 0; i < nsect; i++)

		if ((sechdrs[i].sh_flags & SHF_ALLOC) &&

		if (!sect_empty(&sechdrs[i]) &&

		    (sechdrs[i].sh_type == SHT_NOTE))

			++notes;
@@ -1172,7 +1175,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, 
	notes_attrs->notes = notes;

	nattr = &notes_attrs->attrs[0];

	for (loaded = i = 0; i < nsect; ++i) {

		if (!(sechdrs[i].sh_flags & SHF_ALLOC))

		if (sect_empty(&sechdrs[i]))

			continue;

		if (sechdrs[i].sh_type == SHT_NOTE) {

			nattr->attr.name = mod->sect_attrs->attrs[loaded].name;