[PATCH v6 02/13] selftests/sgx: Fix uninitialized pointer dereferences in encl_get_entry

[Jo Van Bulck]

Ensure sym_tab and sym_names are zero-initialized and add an early-out
condition in the unlikely (erroneous) case that the enclave ELF file would
not contain a symbol table.

This addresses -Werror=maybe-uninitialized compiler warnings for gcc -O2.

Fixes: 33c5aac3bf32 ("selftests/sgx: Test complete changing of page type flow")
Signed-off-by: Jo Van Bulck <jo.vanbu...@cs.kuleuven.be>
Reviewed-by: Jarkko Sakkinen <jar...@kernel.org>
---
 tools/testing/selftests/sgx/load.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/sgx/load.c 
b/tools/testing/selftests/sgx/load.c
index 94bdeac1cf04..c9f658e44de6 100644
--- a/tools/testing/selftests/sgx/load.c
+++ b/tools/testing/selftests/sgx/load.c
@@ -136,11 +136,11 @@ static bool encl_ioc_add_pages(struct encl *encl, struct 
encl_segment *seg)
  */
 uint64_t encl_get_entry(struct encl *encl, const char *symbol)
 {
+       Elf64_Sym *symtab = NULL;
+       char *sym_names = NULL;
        Elf64_Shdr *sections;
-       Elf64_Sym *symtab;
        Elf64_Ehdr *ehdr;
-       char *sym_names;
-       int num_sym;
+       int num_sym = 0;
        int i;
 
        ehdr = encl->bin;
@@ -161,6 +161,9 @@ uint64_t encl_get_entry(struct encl *encl, const char 
*symbol)
                }
        }
 
+       if (!symtab || !sym_names)
+               return 0;
+
        for (i = 0; i < num_sym; i++) {
                Elf64_Sym *sym = &symtab[i];
 
-- 
2.25.1