[PATCH v7 02/13] selftests/sgx: Fix uninitialized pointer dereferences in encl_get_entry

From: Jo Van Bulck
Date: Thu Oct 05 2023 - 12:17:59 EST


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.vanbulck@xxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
---
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