Re: [PATCH v4 10/13] selftests/sgx: Fix uninitialized pointer dereferences

From: Jarkko Sakkinen
Date: Sun Aug 27 2023 - 14:37:05 EST


On Fri Aug 25, 2023 at 4:32 PM EEST, Jo Van Bulck wrote:
> 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>
> ---
> 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

Bug fixes should be always in the head of the patch set.

BR, Jarkko