Linux-Sgx Archive on lore.kernel.org
 help / color / Atom feed
From: Jarkko Sakkinen <jarkko@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
	linux-kselftest@vger.kernel.org,
	Jethro Beekman <jethro@fortanix.com>,
	akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
	asapek@google.com, cedric.xing@intel.com,
	chenalexchen@google.com, conradparker@google.com,
	cyhanish@google.com, dave.hansen@intel.com,
	haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com,
	kmoy@google.com, ludloff@google.com, luto@kernel.org,
	nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com,
	rientjes@google.com, sean.j.christopherson@intel.com,
	tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com
Subject: Re: [PATCH v41 20/24] selftests/x86: Add a selftest for SGX
Date: Tue, 17 Nov 2020 23:38:41 +0200
Message-ID: <20201117213841.GB14833@kernel.org> (raw)
In-Reply-To: <20201117172650.GI5719@zn.tnic>

On Tue, Nov 17, 2020 at 06:26:50PM +0100, Borislav Petkov wrote:
> On Fri, Nov 13, 2020 at 12:01:31AM +0200, Jarkko Sakkinen wrote:
> > +bool encl_load(const char *path, struct encl *encl)
> > +{
> > +	Elf64_Phdr *phdr_tbl;
> > +	off_t src_offset;
> > +	Elf64_Ehdr *ehdr;
> > +	int i, j;
> > +	int ret;
> > +
> > +	memset(encl, 0, sizeof(*encl));
> > +
> > +	ret = open("/dev/sgx_enclave", O_RDWR);
> > +	if (ret < 0) {
> > +		fprintf(stderr, "Unable to open /dev/sgx_enclave\n");
> > +		goto err;
> > +	}
> > +
> > +	encl->fd = ret;
> > +
> > +	if (!encl_map_bin(path, encl))
> > +		goto err;
> > +
> > +	ehdr = encl->bin;
> > +	phdr_tbl = encl->bin + ehdr->e_phoff;
> > +
> > +	for (i = 0; i < ehdr->e_phnum; i++) {
> > +		Elf64_Phdr *phdr = &phdr_tbl[i];
> > +
> > +		if (phdr->p_type == PT_LOAD)
> > +			encl->nr_segments++;
> > +	}
> > +
> > +	encl->segment_tbl = calloc(encl->nr_segments,
> > +				   sizeof(struct encl_segment));
> > +	if (!encl->segment_tbl)
> > +		goto err;
> > +
> > +	for (i = 0, j = 0; i < ehdr->e_phnum; i++) {
> > +		Elf64_Phdr *phdr = &phdr_tbl[i];
> > +		unsigned int flags = phdr->p_flags;
> > +		struct encl_segment *seg;
> > +
> > +		if (phdr->p_type != PT_LOAD)
> > +			continue;
> > +
> > +		seg = &encl->segment_tbl[j];
> > +
> > +		if (!!(flags & ~(PF_R | PF_W | PF_X))) {
> > +			fprintf(stderr,
> > +				"%d has invalid segment flags 0x%02x.\n", i,
> > +				phdr->p_flags);
> > +			goto err;
> > +		}
> > +
> > +		if (j == 0 && flags != (PF_R | PF_W)) {
> > +			fprintf(stderr,
> > +				"TCS has invalid segment flags 0x%02x.\n",
> > +				phdr->p_flags);
> > +			goto err;
> > +		}
> > +
> > +		if (j == 0) {
> > +			src_offset = (phdr->p_offset & PAGE_MASK) - src_offset;
> > +
> > +			seg->prot = PROT_READ | PROT_WRITE;
> > +			seg->flags = SGX_PAGE_TYPE_TCS << 8;
> > +		} else  {
> > +			seg->prot = (phdr->p_flags & PF_R) ? PROT_READ : 0;
> > +			seg->prot |= (phdr->p_flags & PF_W) ? PROT_WRITE : 0;
> > +			seg->prot |= (phdr->p_flags & PF_X) ? PROT_EXEC : 0;
> > +			seg->flags = (SGX_PAGE_TYPE_REG << 8) | seg->prot;
> > +		}
> > +
> > +		seg->offset = (phdr->p_offset & PAGE_MASK) - src_offset;
> > +		seg->size = (phdr->p_filesz + PAGE_SIZE - 1) & PAGE_MASK;
> > +
> > +		printf("0x%016lx 0x%016lx 0x%02x\n", seg->offset, seg->size,
> > +		       seg->prot);
> > +
> > +		j++;
> > +	}
> > +
> > +	assert(j == encl->nr_segments);
> > +
> > +	encl->src = encl->bin + src_offset;
> > +	encl->src_size = encl->segment_tbl[j - 1].offset +
> > +			 encl->segment_tbl[j - 1].size;
> > +
> > +	for (encl->encl_size = 4096; encl->encl_size < encl->src_size; )
> > +		encl->encl_size <<= 1;
> 
> Something's fishy. That selftest fails with
> 
> mmap: Cannot allocate memory
> 
> I sprinkled some printfs at this size computation above and here's what
> it says:
> 
> 0x00007fdd3b4ca190 0x0000000000002000 0x03
> 0x00007fdd3b4cc190 0x0000000000001000 0x05
> 0x00007fdd3b4cd190 0x0000000000003000 0x03
> encl_load: encl->nr_segments: 3
> encl_load: seg2 offset: 0x7fdd3b4cd190, seg2 size: 12288
> encl_load: encl_size: 140737488355328, src_size: 140588159402384
> encl_map_area: encl_size: 140737488355328
> mmap: Cannot allocate memory

In my machine, with the current version:

➜  sgx (master) ✗ ./test_sgx
0x0000000000000000 0x0000000000002000 0x03
0x0000000000002000 0x0000000000001000 0x05
0x0000000000003000 0x0000000000003000 0x03
SUCCESS

This the bug, src_offset initialization:

diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c
index 07988de6b767..9d43b75aaa55 100644
--- a/tools/testing/selftests/sgx/load.c
+++ b/tools/testing/selftests/sgx/load.c
@@ -185,7 +185,7 @@ bool encl_load(const char *path, struct encl *encl)
                }
 
                if (j == 0) {
-                       src_offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+                       src_offset = phdr->p_offset & PAGE_MASK;
 
                        seg->prot = PROT_READ | PROT_WRITE;
                        seg->flags = SGX_PAGE_TYPE_TCS << 8;

This was introduced when moving from converting elf to bin to load
directly from elf. In my case 'src_offset' happened to be zero and
I have not thus noticed this before.

/Jarkko

  parent reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12 22:01 [PATCH v41 00/24] Intel SGX foundations Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 01/24] x86/sgx: Add SGX architectural data structures Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 02/24] x86/sgx: Add wrappers for ENCLS functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 03/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 04/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 05/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-11-16 22:25   ` [PATCH] x86/sgx: clarify 'laundry_list' locking Dave Hansen
2020-11-17 19:29     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 06/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 07/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 08/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 09/24] x86/sgx: Add SGX page allocator functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-11-13 10:25   ` Mel Gorman
2020-11-17 18:16     ` Jarkko Sakkinen
2020-11-15 17:08   ` Dr. Greg
2020-11-15 17:32   ` Matthew Wilcox
2020-11-15 18:36     ` Dave Hansen
2020-11-16 10:09       ` Mel Gorman
2020-11-17 19:15         ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 11/24] x86/sgx: Add SGX misc driver interface Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
     [not found]   ` <20201115044044.11040-1-hdanton@sina.com>
2020-11-17 17:35     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 16/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 17/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 18/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 19/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-11-17 13:14   ` Borislav Petkov
2020-11-17 19:41     ` Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 20/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-11-16 18:19   ` Shuah Khan
2020-11-17 13:22     ` Borislav Petkov
2020-11-17 19:42     ` Jarkko Sakkinen
2020-11-17 17:26   ` Borislav Petkov
2020-11-17 21:27     ` Jarkko Sakkinen
2020-11-17 21:38     ` Jarkko Sakkinen [this message]
2020-11-12 22:01 ` [PATCH v41 21/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 22/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 23/24] docs: x86/sgx: Document SGX kernel architecture Jarkko Sakkinen
2020-11-12 22:01 ` [PATCH v41 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-11-16 16:55 ` [PATCH v41 00/24] Intel SGX foundations Borislav Petkov
2020-11-16 17:21   ` Dave Hansen
2020-11-16 17:28     ` Borislav Petkov
2020-11-17 19:20       ` Jarkko Sakkinen
     [not found] ` <20201114084211.5284-1-hdanton@sina.com>
2020-11-16 18:33   ` [PATCH v41 05/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Dave Hansen
     [not found] ` <20201115040127.7804-1-hdanton@sina.com>
2020-11-16 21:11   ` [PATCH v41 11/24] x86/sgx: Add SGX misc driver interface Dave Hansen
     [not found] ` <20201114090708.8684-1-hdanton@sina.com>
2020-11-17 18:12   ` [PATCH v41 06/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
     [not found] ` <20201114093256.7800-1-hdanton@sina.com>
2020-11-17 18:14   ` [PATCH v41 09/24] x86/sgx: Add SGX page allocator functions Jarkko Sakkinen
     [not found] ` <20201115030548.1572-1-hdanton@sina.com>
2020-11-17 18:22   ` [PATCH v41 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-12-15  5:38 ` [PATCH v41 00/24] Intel SGX foundations Hui, Chunyang
2020-12-15  5:43 ` Hui, Chunyang
2020-12-15 15:58   ` Jarkko Sakkinen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201117213841.GB14833@kernel.org \
    --to=jarkko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=asapek@google.com \
    --cc=bp@alien8.de \
    --cc=cedric.xing@intel.com \
    --cc=chenalexchen@google.com \
    --cc=conradparker@google.com \
    --cc=cyhanish@google.com \
    --cc=dave.hansen@intel.com \
    --cc=haitao.huang@intel.com \
    --cc=jethro@fortanix.com \
    --cc=kai.huang@intel.com \
    --cc=kai.svahn@intel.com \
    --cc=kmoy@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-sgx@vger.kernel.org \
    --cc=ludloff@google.com \
    --cc=luto@kernel.org \
    --cc=mikko.ylinen@intel.com \
    --cc=nhorman@redhat.com \
    --cc=npmccallum@redhat.com \
    --cc=puiterwijk@redhat.com \
    --cc=rientjes@google.com \
    --cc=sean.j.christopherson@intel.com \
    --cc=shuah@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    --cc=yaozhangx@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Sgx Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-sgx/0 linux-sgx/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-sgx linux-sgx/ https://lore.kernel.org/linux-sgx \
		linux-sgx@vger.kernel.org
	public-inbox-index linux-sgx

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-sgx


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git