[PATCH] objtool: prevent memory leak in error paths

Muhammad Usama Anjum
2021-04-13T20:45:24Z

Memory allocated by sym and sym->name isn't being freed if some error
occurs in elf_create_undef_symbol(). Free the sym and sym->name if error
is detected before returning NULL.

Addresses-Coverity: ("Prevent memory leak")
Fixes: 2f2f7e47f052 ("objtool: Add elf_create_undef_symbol()")
Signed-off-by: Muhammad Usama Anjum <musamaanjum@gmail.com>
---
Only build has been tested.

tools/objtool/elf.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d08f5f3670f8..17ee265a6c6b 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -733,7 +733,7 @@ struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)

sym->sym.st_name = elf_add_string(elf, NULL, sym->name);
if (sym->sym.st_name == -1)
- return NULL;
+ goto err;

sym->sym.st_info = GELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
// st_other 0
@@ -744,19 +744,19 @@ struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
symtab = find_section_by_name(elf, ".symtab");
if (!symtab) {
WARN("can't find .symtab");
- return NULL;
+ goto err;
}

s = elf_getscn(elf->elf, symtab->idx);
if (!s) {
WARN_ELF("elf_getscn");
- return NULL;
+ goto err;
}

data = elf_newdata(s);
if (!data) {
WARN_ELF("elf_newdata");
- return NULL;
+ goto err;
}

data->d_buf = &sym->sym;
@@ -773,6 +773,10 @@ struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
elf_add_symbol(elf, sym);

return sym;
+err:
+ free(sym->name);
+ free(sym);
+ return NULL;
}

struct section *elf_create_section(struct elf *elf, const char *name,
--
2.25.1