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@xxxxxxxxxxxxx>
Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Cc: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-sgx@xxxxxxxxxxxxxxx
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
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);
_
