SLIDE 1
Obliviate: A Data Oblivious File System for Intel SGX
Adil Ahmad Kyungtae Kim Muhammad Ihsanulhaq Sarfaraz Byoungyoung Lee
1
Clouds? The Ultimate Dream?
Clouds User
2
System for Intel SGX Adil Ahmad Kyungtae Kim Muhammad Ihsanulhaq - - PowerPoint PPT Presentation
System for Intel SGX Adil Ahmad Kyungtae Kim Muhammad Ihsanulhaq - - PowerPoint PPT Presentation
Obliviate: A Data Oblivious File System for Intel SGX Adil Ahmad Kyungtae Kim Muhammad Ihsanulhaq Sarfaraz Byoungyoung Lee 1 Clouds? The Ultimate Dream? User Clouds 2 Clouds? The Ultimate Dream? User Clouds 2 Clouds? The Ultimate
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SLIDE 3
Clouds? The Ultimate Dream?
Clouds User
2
SLIDE 4
Clouds? The Ultimate Dream?
Clouds User Hmm, SGX??
2
SLIDE 5
Clouds? The Ultimate Dream?
Clouds User Hmm, SGX??
2
SLIDE 6
Clouds? The Ultimate Dream?
Clouds User Hmm, SGX??
2
SLIDE 7
Clouds? The Ultimate Dream?
Clouds User Hmm, SGX?? Thanks, SGX?! ☺
2
SLIDE 8
Clouds? The Ultimate Dream?
Clouds User Hmm, SGX?? Thanks, SGX?! ☺
2
The real world is a bit more complicated!
SLIDE 9
The sorcery behind SGX
Program’s Address Space
3
SLIDE 10
The sorcery behind SGX
Program’s Address Space Non- Enclave Enclave
3
Confidentiality and integrity- protected T rusted execution region
SLIDE 11
The sorcery behind SGX
Program’s Address Space Non- Enclave Enclave System Components Restricted by the processor
3
Confidentiality and integrity- protected T rusted execution region
SLIDE 12
Possible SGX File Systems
Disk
4
SLIDE 13
Possible SGX File Systems
Disk
Enclaves are ring-3
4
SLIDE 14
Possible SGX File Systems
Disk
Enclaves are ring-3 Rely on OS for ring-0 ops Operating System
4
SLIDE 15
Possible SGX File Systems
Disk
Enclaves are ring-3
1.
- pen(“a.txt”);
2. read(2, 0x1000, 4096); 3. ….
Rely on OS for ring-0 ops Operating System
4
SLIDE 16
Possible SGX File Systems
Disk
Enclaves are ring-3
1.
- pen(“a.txt”);
2. read(2, 0x1000, 4096); 3. ….
Rely on OS for ring-0 ops Operating System Allow OS to handle file buffer (native)
4
SLIDE 17
Possible SGX File Systems
Disk
Enclaves are ring-3
1.
- pen(“a.txt”);
2. read(2, 0x1000, 4096); 3. ….
Rely on OS for ring-0 ops Operating System Allow OS to handle file buffer (native) Buffer the file within the enclave (in-memory)
4
SLIDE 18
Side-channel attacks against in-memory FS
Operating System Enclave
Page table attacks against SGX
[S&P14, SEC17] Cache attacks against SGX [DIMVA17, WOOT17, EuroSec17]
5
Data.txt
SLIDE 19
Side-channel attacks against in-memory FS
Access Frame #
0x1000 0x1001 0x1002 0x1003 0x1004
Page T able
Operating System Enclave Accessed by the enclave
Page table attacks against SGX
[S&P14, SEC17] Cache attacks against SGX [DIMVA17, WOOT17, EuroSec17]
5
Data.txt
SLIDE 20
Side-channel attacks against in-memory FS
Access Frame #
0x1000 0x1001 0x1002 0x1003 0x1004
Page T able
Operating System Enclave Accessed by the enclave
1 0x1000 1 0x1003
Page table attacks against SGX
[S&P14, SEC17] Cache attacks against SGX [DIMVA17, WOOT17, EuroSec17]
5
Data.txt
SLIDE 21
Side-channel attacks against in-memory FS
Access Frame #
0x1000 0x1001 0x1002 0x1003 0x1004
Page T able
Operating System Enclave Accessed by the enclave
1 0x1000 1 0x1003
Page table attacks against SGX
[S&P14, SEC17] cache-set 0 cache-set 1 cache-set 2 cache-set 3
Cache
Cache attacks against SGX [DIMVA17, WOOT17, EuroSec17]
5
Data.txt
SLIDE 22
Side-channel attacks against in-memory FS
Access Frame #
0x1000 0x1001 0x1002 0x1003 0x1004
Page T able
Operating System Enclave Accessed by the enclave
1 0x1000 1 0x1003
Page table attacks against SGX
[S&P14, SEC17] cache-set 0 cache-set 1 cache-set 2 cache-set 3
Cache
cache-set 0 cache-set 3 Cache attacks against SGX [DIMVA17, WOOT17, EuroSec17]
5
Data.txt
SLIDE 23
Case Study: Attacking SQlite
Doctor Cloud
6
SLIDE 24
Case Study: Attacking SQlite
Doctor Doctor attempts to access a patient’s history Cloud
6
SLIDE 25
Case Study: Attacking SQlite
Query1: Bob’s heart history Doctor Doctor attempts to access a patient’s history Cloud
6
Query2: Alice’s heart history
SLIDE 26
Case Study: Attacking SQlite
Query1: Bob’s heart history Doctor SGX-protected SQLite Doctor attempts to access a patient’s history Cloud
6
Query2: Alice’s heart history
SLIDE 27
Case Study: Attacking SQlite
Name Lungs Condition Heart condition
Query1: Bob’s heart history Doctor SGX-protected SQLite Doctor attempts to access a patient’s history Cloud
6
Query2: Alice’s heart history
SLIDE 28
What the attacker sees?
med.db
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Alice
…
Eve
… … …
SLIDE 29
What the attacker sees?
med.db
Query1: Bob’s heart history
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
SLIDE 30
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
SLIDE 31
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Page T able Attack
Time Address
SLIDE 32
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Page T able Attack Query1
Time Address
SLIDE 33
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Alice
…
Page T able Attack
Time Address
Query2: Alice’s heart history
SLIDE 34
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768); 1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,40960);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Alice
…
Page T able Attack
Time Address
Query2: Alice’s heart history
SLIDE 35
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768); 1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,40960);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Alice
…
Page T able Attack
Time Address
Query2 Query2: Alice’s heart history
SLIDE 36
What the attacker sees?
med.db
Query1: Bob’s heart history
1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,32768); 1.
- pen(”med.db”
, ..); 2. pread64(…,4096,0); 3. pread64(…,4096,4096); 4. pread64(…,4096,40960);
Syscall Snooping Attack
Name
Bob
…
Lung Condition
…
Heart condition
… … …
Bob
…
Alice
…
Eve
… … …
Alice
…
Page T able Attack
Time Address
Query2 Query2: Alice’s heart history
Predictable access patterns in file operations leak sensitive information!
SLIDE 37
What should we do?
8
SLIDE 38
What should we do?
Masking individual memory side-channels is risky
8
SLIDE 39
What should we do?
Masking individual memory side-channels is risky Memory side-channels rely on predictable access patterns
8
SLIDE 40
What should we do?
Masking individual memory side-channels is risky Memory side-channels rely on predictable access patterns How to provide strong protection despite memory traces?
8
SLIDE 41
What should we do?
Masking individual memory side-channels is risky Memory side-channels rely on predictable access patterns How to provide strong protection despite memory traces?
8
Oblivious RAM is one possible solution to this problem
SLIDE 42
Oblivious RAM
User Clouds
B D E C F A
User’s goal:
Securely access data stored in the cloud
Attacker’s goal:
Figure out what data-block is being accessed
9
SLIDE 43
Path ORAM
Improved variant of Oblivious RAM [Stephanov et. al, CCS12]
d d C A B d D
Server
A 00 B 01 C 10 D 11
Position Map
Client
Stash
stores position
- f block
stores acquired blocks holds encrypted real blocks and dummy blocks
ORAM T ree
1 1 1
d
dummy
A
real
Legend
10
SLIDE 44
11
SLIDE 45
11
SLIDE 46
OBLIVIA TE!
11
SLIDE 47
OBLIVIA TE!
11
SLIDE 48
Obliviate: memory charm against the OS ☺
Obliviate
Filesystem Enclave Application Enclave
Disk
12
SLIDE 49
Obliviate: memory charm against the OS ☺
Obliviate
Filesystem Enclave Application Enclave
Disk
12
(Init) load all files into ORAM T ree(s)
ORAM Trees
C A B D
SLIDE 50
Obliviate: memory charm against the OS ☺
T rusted Proxy
- 1. FS Syscall
Interceptor
Obliviate
Filesystem Enclave Application Enclave
Disk
12
ORAM Trees
C A B D
SLIDE 51
Obliviate: memory charm against the OS ☺
T rusted Proxy
Obliviate
- 2. Encrypted
Channel
Filesystem Enclave Application Enclave
Disk
12
ORAM Trees
C A B D
SLIDE 52
Obliviate: memory charm against the OS ☺
T rusted Proxy
Obliviate
Filesystem Enclave Application Enclave
Disk
12
ORAM Trees
C A B D
- 3. Data Oblivious
Metadata Handling
SLIDE 53
Obliviate: memory charm against the OS ☺
T rusted Proxy
Obliviate
Filesystem Enclave Application Enclave
Disk
12
ORAM Trees
C A B D
- 4. Asynchronous
ORAM Operation
SLIDE 54
Obliviate: memory charm against the OS ☺
T rusted Proxy
Obliviate
Filesystem Enclave Application Enclave
Disk
- 5. Extended
Secure Region
12
ORAM Trees
C A B D
SLIDE 55
Decoupling file system support
Disk
Application Enclaves Obliviate
13
SLIDE 56
Decoupling file system support
Disk
Application Enclaves Obliviate
Pass all FS syscalls using encrypted channel
13
SLIDE 57
Decoupling file system support
Allow Obliviate to worry about securing file access
Disk
Application Enclaves Obliviate
Pass all FS syscalls using encrypted channel
13
SLIDE 58
Decoupling file system support
Allow Obliviate to worry about securing file access
Disk
Application Enclaves Obliviate
Pass all FS syscalls using encrypted channel
13
Separation of functions facilitates development!
SLIDE 59
Legacy application support
Application
14
SLIDE 60
Legacy application support
Intercept FS syscalls and encrypt
T rusted Proxy
Application
14
SLIDE 61
Legacy application support
Intercept FS syscalls and encrypt
T rusted Proxy
Exit-less message queue
(SCONE [OSDI16], ELEOS [EuroSys17]) Application
Oblivate
Disk
14
SLIDE 62
Legacy application support
Intercept FS syscalls and encrypt
T rusted Proxy
Exit-less message queue
(SCONE [OSDI16], ELEOS [EuroSys17]) Application
Oblivate
Disk
14
No changes from the app developer!
SLIDE 63
Securing ORAM
Obliviate
Disk
15
Application
SLIDE 64
Securing ORAM
Obliviate
Disk
Position Map Stash
ORAM client
15
Need to store metadata in enclave
Application
SLIDE 65
Securing ORAM
Obliviate
Disk
Position Map Stash
ORAM client
Obliviate’s enclave is not side-channel free
15
Application
SLIDE 66
Securing ORAM
Position Map
Obliviate
Disk
Position Map Stash
ORAM client
15
Application
SLIDE 67
Securing ORAM
Position Map
Load from index
Obliviate
Disk
Position Map Stash
ORAM client
15
Application
SLIDE 68
Securing ORAM
Position Map
Access Frame #0x1000 0x1001 0x1002 0x1003
Page T able
cache-set 0 cache-set 1 cache-set 2
cache-set 3
Last-Level Cache
1 0x1003
Obliviate
Disk
Position Map Stash
ORAM client
15
Application
SLIDE 69
Securing ORAM
Position Map
Use Conditional Move (CMOV)
Access Frame #0x1000 0x1001 0x1002 0x1003
Page T able
cache-set 0 cache-set 1 cache-set 2
cache-set 3
Last-Level Cache
1 0x1003
Obliviate
Disk
Position Map Stash
ORAM client
15
Application
SLIDE 70
Securing ORAM
Position Map
Use Conditional Move (CMOV)
Access Frame #0x1000 0x1001 0x1002 0x1003
Page T able
cache-set 0 cache-set 1 cache-set 2
cache-set 3
Last-Level Cache
cache-set 0 cache-set 1 cache-set 2
1 0x1003 1 0x1000 1 0x1001 1 0x1002
Obliviate
Disk
Position Map Stash
ORAM client
15
Application
SLIDE 71
Securing ORAM
Position Map
Use Conditional Move (CMOV)
Access Frame #0x1000 0x1001 0x1002 0x1003
Page T able
cache-set 0 cache-set 1 cache-set 2
cache-set 3
Last-Level Cache
cache-set 0 cache-set 1 cache-set 2
1 0x1003 1 0x1000 1 0x1001 1 0x1002
Obliviate
Disk
Position Map Stash
ORAM client
15
The attacker cannot distinguish CMOV from MOV
Application
SLIDE 72
Securing ORAM
Position Map
Use Conditional Move (CMOV)
Access Frame #0x1000 0x1001 0x1002 0x1003
Page T able
cache-set 0 cache-set 1 cache-set 2
cache-set 3
Last-Level Cache
cache-set 0 cache-set 1 cache-set 2
1 0x1003 1 0x1000 1 0x1001 1 0x1002
Obliviate
Disk
Position Map Stash
ORAM client
15
The attacker cannot distinguish CMOV from MOV
Application
Side-channel resistant ORAM implementation!
SLIDE 73
Extending Enclave Memory
16
Obliviate Disk
SLIDE 74
Extending Enclave Memory
16
EPC Physical Memory Program
Obliviate Disk
Large enclaves degrade performance
SLIDE 75
Extending Enclave Memory
Metadata (small) inside enclave ORAM Trees (large) outside enclave
16
EPC Physical Memory Program
Obliviate Disk
Encrypted ORAM Trees
C A B D
Position Map Stash
ORAM Client
Large enclaves degrade performance
SLIDE 76
Extending Enclave Memory
Metadata (small) inside enclave ORAM Trees (large) outside enclave
16
EPC Physical Memory Program
Obliviate Disk
Encrypted ORAM Trees
C A B D
Position Map Stash
ORAM Client
Large enclaves degrade performance
Encrypted ORAM trees outside enclave!
SLIDE 77
Leveraging asynchronicity
Communication Thread Operation Thread
Obliviate
17
Disk
Encrypted ORAM Trees
C A B D
Application
SLIDE 78
Leveraging asynchronicity
Communication Thread Operation Thread
Obliviate
17
Disk
Encrypted ORAM Trees
C A B D
Application
(a) read(1, 0x18289, 4096)
SLIDE 79
Leveraging asynchronicity
Communication Thread Operation Thread
Obliviate
17
Disk
Encrypted ORAM Trees
C A B D
(b) Read(A)
Application
(a) read(1, 0x18289, 4096)
SLIDE 80
Leveraging asynchronicity
Communication Thread Operation Thread
Obliviate
17
(c) Reply to the request
Disk
Encrypted ORAM Trees
C A B D
(c) Write-back(A) (b) Read(A)
Application
(a) read(1, 0x18289, 4096)
SLIDE 81
Leveraging asynchronicity
Communication Thread Operation Thread
Obliviate
17
(c) Reply to the request
Disk
Encrypted ORAM Trees
C A B D
(c) Write-back(A) (b) Read(A)
Application
(a) read(1, 0x18289, 4096)
Perform Asynchronous ORAM write-back!
SLIDE 82
Implementation
1. Obliviate runs using Intel SGX SDK Library 2. Graphene-SGX integration to run “heavyweight” applications, e.g., SQLite and Lighttpd
18
SLIDE 83
Performance Evaluation
Evaluated filesystems:
- 1. Native Filesystem (Non-SGX)
- 2. In-memory Filesystem (SGX, based on Graphene-SGX)
- 3. Obliviate (SGX, based on Intel SGX SDK)
19
SLIDE 84
Iozone Benchmarks
a) Sequential Reads (Bytes/sec) b) Sequential Writes (Bytes/sec)
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
20
SLIDE 85
Iozone Benchmarks
a) Sequential Reads (Bytes/sec) b) Sequential Writes (Bytes/sec)
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
2-3x overhead over the in-memory FS
20
SLIDE 86
Iozone Benchmarks
a) Sequential Reads (Bytes/sec) b) Sequential Writes (Bytes/sec) In-memory FS exerts a lot of pressure on EPC
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
2-3x overhead over the in-memory FS
20
SLIDE 87
Iozone Benchmarks
a) Sequential Reads (Bytes/sec) b) Sequential Writes (Bytes/sec) Comparable performance for smaller file sizes In-memory FS exerts a lot of pressure on EPC
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
1 10 100 1000 10000 100000 1000000 10000000
2M 128M 512M 1G
Native FS In-memory FS Obliviate
2-3x overhead over the in-memory FS
20
SLIDE 88
Macro-Benchmarks
a) SQLite Response Times (milli-sec) b) Lighttpd Throughput (Req/s)
100 1000 10000
1K 16K 128K 1M
In-memory FS Obliviate
500 1000 1500 2000 2500
INSERT SELECT
In-memory FS Obliviate
21
SLIDE 89
Macro-Benchmarks
a) SQLite Response Times (milli-sec) b) Lighttpd Throughput (Req/s) ~2x overhead over in-memory FS
100 1000 10000
1K 16K 128K 1M
In-memory FS Obliviate
500 1000 1500 2000 2500
INSERT SELECT
In-memory FS Obliviate
21
SLIDE 90
Conclusion
22
SLIDE 91
Conclusion
- 1. All existing SGX filesystems are vulnerable to side-channels
22
SLIDE 92
Conclusion
- 1. All existing SGX filesystems are vulnerable to side-channels
- 2. File system operations can leak sensitive information about program
execution.
22
SLIDE 93
Conclusion
- 1. All existing SGX filesystems are vulnerable to side-channels
- 2. File system operations can leak sensitive information about program
execution.
- 3. Obliviate provides theoretically-strong defense against side-
channels.
22
SLIDE 94
Conclusion
- 1. All existing SGX filesystems are vulnerable to side-channels
- 2. File system operations can leak sensitive information about program
execution.
- 3. Obliviate provides theoretically-strong defense against side-
channels.
22
Opensource: https://github.com/adilahmad17/Obliviate Contact: ahmad37@purdue.edu
SLIDE 95
Thanks! Merci! Shukriya!
23
SLIDE 96
Extra Slides
24
SLIDE 97
Securing file system
25
SLIDE 98
Securing file system
c a b d
25
SLIDE 99
Securing file system
c a b d
Single ORAM Tree protects file offset
25
SLIDE 100
Securing file system
c a b d c a b d c a b d c a b d c a b d c a b d c a b d
Hierarchical ORAM Trees can protect files Single ORAM Tree protects file offset
25
SLIDE 101
Securing file system
c a b d c a b d c a b d c a b d c a b d c a b d c a b d
Hierarchical ORAM Trees can protect files Single ORAM Tree protects file offset
Protect both file and file offset!
25