The SGX selftests can fail for a bunch of non-obvious reasons like 'noexec' permissions on /dev (which is the default *EVERYWHERE* it seems).
A new test mistakenly also looked for +x permission on the /dev/sgx_enclave. File execute permissions really only apply to the ability of execve() to work on a file, *NOT* on the ability for an application to map the file with PROT_EXEC. SGX needs to mmap(PROT_EXEC), but doesn't need to execve() the device file.
Remove the check.
Fixes: 4284f7acb78b ("selftests/sgx: Improve error detection and messages") Reported-by: Tim Gardner tim.gardner@canonical.com Cc: Jarkko Sakkinen jarkko@kernel.org Cc: Reinette Chatre reinette.chatre@intel.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Shuah Khan shuah@kernel.org Cc: linux-sgx@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org
---
b/tools/testing/selftests/sgx/load.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-)
diff -puN tools/testing/selftests/sgx/load.c~sgx-no-file-exec tools/testing/selftests/sgx/load.c --- a/tools/testing/selftests/sgx/load.c~sgx-no-file-exec 2021-06-21 11:48:25.226294281 -0700 +++ b/tools/testing/selftests/sgx/load.c 2021-06-21 12:03:28.023292029 -0700 @@ -150,16 +150,6 @@ bool encl_load(const char *path, struct goto err; }
- /* - * This just checks if the /dev file has these permission - * bits set. It does not check that the current user is - * the owner or in the owning group. - */ - if (!(sb.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))) { - fprintf(stderr, "no execute permissions on device file %s\n", device_path); - goto err; - } - ptr = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0); if (ptr == (void *)-1) { perror("mmap for read"); @@ -169,13 +159,13 @@ bool encl_load(const char *path, struct
#define ERR_MSG \ "mmap() succeeded for PROT_READ, but failed for PROT_EXEC.\n" \ -" Check that current user has execute permissions on %s and \n" \ -" that /dev does not have noexec set: mount | grep "/dev .*noexec"\n" \ +" Check that /dev does not have noexec set:\n" \ +" \tmount | grep "/dev .*noexec"\n" \ " If so, remount it executable: mount -o remount,exec /dev\n\n"
ptr = mmap(NULL, PAGE_SIZE, PROT_EXEC, MAP_SHARED, fd, 0); if (ptr == (void *)-1) { - fprintf(stderr, ERR_MSG, device_path); + fprintf(stderr, ERR_MSG); goto err; } munmap(ptr, PAGE_SIZE); _