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); _
Hi Dave,
On 6/21/2021 12:05 PM, Dave Hansen wrote:
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
Thank you very much for fixing this. With this applied the SGX tests are able to run again on my system.
Tested-by: Reinette Chatre reinette.chatre@intel.com
I think it is missing a "Signed-off-by".
Reinette
On 6/21/21 2:08 PM, Reinette Chatre wrote:
Thank you very much for fixing this. With this applied the SGX tests are able to run again on my system.
Tested-by: Reinette Chatre reinette.chatre@intel.com
I think it is missing a "Signed-off-by".
Right you are. I think I've done this twice in a row for one-off patches. Sheesh.
Signed-off-by: Dave Hansen dave.hansen@linux.intel.com
If anyone wants a resend with this included, please let me know.
On 6/21/21 3:18 PM, Dave Hansen wrote:
On 6/21/21 2:08 PM, Reinette Chatre wrote:
Thank you very much for fixing this. With this applied the SGX tests are able to run again on my system.
Tested-by: Reinette Chatre reinette.chatre@intel.com
I think it is missing a "Signed-off-by".
Right you are. I think I've done this twice in a row for one-off patches. Sheesh.
Signed-off-by: Dave Hansen dave.hansen@linux.intel.com
If anyone wants a resend with this included, please let me know.
Thanks to b4/patchwork - no need to resend. I have the signed-off-by in the downloaded patch.
Thank you all. Now applied to linux-kselftest next for 5.14-rc1
-- Shuah
On Mon, Jun 21, 2021 at 12:05:56PM -0700, Dave Hansen wrote:
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);_
Reviewed-by: Jarkko Sakkinen jarkko@kernel.org
/Jarkko
linux-kselftest-mirror@lists.linaro.org
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Dave Hansen -
Dave Hansen -
Jarkko Sakkinen -
Reinette Chatre -
Shuah Khan