Commit 28fe1d7b authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Peter Zijlstra
Browse files

objtool: use gelf_getsymshndx to handle >64k sections 



Currently, objtool fails to load the correct section for symbols when
the index is greater than SHN_LORESERVE. Use gelf_getsymshndx instead
of gelf_getsym to handle >64k sections.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200421220843.188260-2-samitolvanen@google.com
parent ab3852ab

tools/objtool/elf.c

+17 −7
Original line number Diff line number Diff line
@@ -343,12 +343,14 @@ static int read_sections(struct elf *elf) 


static int read_symbols(struct elf *elf)

{

	struct section *symtab, *sec;

	struct section *symtab, *symtab_shndx, *sec;

	struct symbol *sym, *pfunc;

	struct list_head *entry;

	struct rb_node *pnode;

	int symbols_nr, i;

	char *coldstr;

	Elf_Data *shndx_data = NULL;

	Elf32_Word shndx;



	symtab = find_section_by_name(elf, ".symtab");

	if (!symtab) {
@@ -356,6 +358,10 @@ static int read_symbols(struct elf *elf) 
		return -1;

	}



	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");

	if (symtab_shndx)

		shndx_data = symtab_shndx->data;



	symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;



	for (i = 0; i < symbols_nr; i++) {
@@ -369,8 +375,9 @@ static int read_symbols(struct elf *elf) 


		sym->idx = i;



		if (!gelf_getsym(symtab->data, i, &sym->sym)) {

			WARN_ELF("gelf_getsym");

		if (!gelf_getsymshndx(symtab->data, shndx_data, i, &sym->sym,

				      &shndx)) {

			WARN_ELF("gelf_getsymshndx");

			goto err;

		}
@@ -384,10 +391,13 @@ static int read_symbols(struct elf *elf) 
		sym->type = GELF_ST_TYPE(sym->sym.st_info);

		sym->bind = GELF_ST_BIND(sym->sym.st_info);



		if (sym->sym.st_shndx > SHN_UNDEF &&

		    sym->sym.st_shndx < SHN_LORESERVE) {

			sym->sec = find_section_by_index(elf,

							 sym->sym.st_shndx);

		if ((sym->sym.st_shndx > SHN_UNDEF &&

		     sym->sym.st_shndx < SHN_LORESERVE) ||

		    (shndx_data && sym->sym.st_shndx == SHN_XINDEX)) {

			if (sym->sym.st_shndx != SHN_XINDEX)

				shndx = sym->sym.st_shndx;



			sym->sec = find_section_by_index(elf, shndx);

			if (!sym->sec) {

				WARN("couldn't find section for symbol %s",

				     sym->name);

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