Add a unit test for CRYPT_ArcFourSetup().

BUG=chromium:686128

Change-Id: Iad3ebbfd304dc145af2e694818864c4d25ccf99a
Reviewed-on: https://pdfium-review.googlesource.com/4793
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

3 files changed, 74 insertions, 13 deletions

diff --git a/core/fdrm/crypto/fx_crypt.cpp b/core/fdrm/crypto/fx_crypt.cpp
index f4ead91d33..f5ebdf09d2 100644
--- a/core/fdrm/crypto/fx_crypt.cpp
+++ b/core/fdrm/crypto/fx_crypt.cpp
@@ -143,11 +143,11 @@ void CRYPT_ArcFourSetup(CRYPT_rc4_context* s,
                         uint32_t length) {
   s->x = 0;
   s->y = 0;
-  for (int i = 0; i < 256; ++i)
+  for (int i = 0; i < kRC4ContextPermutationLength; ++i)
     s->m[i] = i;
 
   int j = 0;
-  for (int i = 0; i < 256; ++i) {
+  for (int i = 0; i < kRC4ContextPermutationLength; ++i) {
     j = (j + s->m[i] + (length ? key[i % length] : 0)) & 0xFF;
     std::swap(s->m[i], s->m[j]);
   }
diff --git a/core/fdrm/crypto/fx_crypt.h b/core/fdrm/crypto/fx_crypt.h
index cfbe119ddb..2b127948f0 100644
--- a/core/fdrm/crypto/fx_crypt.h
+++ b/core/fdrm/crypto/fx_crypt.h
@@ -9,37 +9,38 @@
 
 #include "core/fxcrt/fx_system.h"
 
-typedef struct {
+constexpr int32_t kRC4ContextPermutationLength = 256;
+struct CRYPT_rc4_context {
   int32_t x;
   int32_t y;
-  int32_t m[256];
-} CRYPT_rc4_context;
+  int32_t m[kRC4ContextPermutationLength];
+};
 
-typedef struct {
+struct CRYPT_md5_context {
   uint32_t total[2];
   uint32_t state[4];
   uint8_t buffer[64];
-} CRYPT_md5_context;
+};
 
-typedef struct {
+struct CRYPT_sha1_context {
   unsigned int h[5];
   unsigned char block[64];
   int blkused;
   unsigned int lenhi;
   unsigned int lenlo;
-} CRYPT_sha1_context;
+};
 
-typedef struct {
+struct CRYPT_sha256_context {
   uint32_t total[2];
   uint32_t state[8];
   uint8_t buffer[64];
-} CRYPT_sha256_context;
+};
 
-typedef struct {
+struct CRYPT_sha384_context {
   uint64_t total[2];
   uint64_t state[8];
   uint8_t buffer[128];
-} CRYPT_sha384_context;
+};
 
 void CRYPT_ArcFourCryptBlock(uint8_t* data,
                              uint32_t size,
diff --git a/core/fdrm/crypto/fx_crypt_unittest.cpp b/core/fdrm/crypto/fx_crypt_unittest.cpp
index f5fb457d3d..247da07233 100644
--- a/core/fdrm/crypto/fx_crypt_unittest.cpp
+++ b/core/fdrm/crypto/fx_crypt_unittest.cpp
@@ -214,3 +214,63 @@ TEST(FXCRYPT, Sha256TestB2) {
   for (size_t i = 0; i < 32; ++i)
     EXPECT_EQ(expected[i], actual[i]) << " at byte " << i;
 }
+
+TEST(FXCRYPT, CRYPT_ArcFourSetup) {
+  {
+    const uint8_t kNullPermutation[kRC4ContextPermutationLength] = {
+        0,   35,  3,   43,  9,   11,  65,  229, 32,  36,  134, 98,  59,  34,
+        173, 153, 214, 200, 64,  161, 191, 62,  6,   25,  56,  234, 49,  246,
+        69,  133, 203, 194, 10,  42,  228, 198, 195, 245, 236, 91,  206, 23,
+        235, 27,  138, 18,  143, 250, 244, 76,  123, 217, 132, 249, 72,  127,
+        94,  151, 33,  60,  248, 85,  177, 210, 142, 83,  110, 140, 41,  135,
+        196, 238, 156, 242, 141, 67,  5,   185, 131, 63,  137, 37,  172, 121,
+        70,  144, 237, 130, 17,  44,  253, 166, 78,  201, 12,  119, 215, 7,
+        126, 114, 97,  192, 53,  4,   254, 45,  102, 122, 230, 88,  193, 129,
+        160, 124, 84,  108, 239, 189, 152, 120, 115, 207, 50,  176, 86,  157,
+        164, 187, 71,  1,   15,  58,  29,  21,  46,  145, 247, 162, 95,  183,
+        13,  226, 159, 175, 221, 100, 96,  202, 101, 178, 154, 47,  205, 106,
+        148, 104, 93,  112, 26,  165, 128, 186, 146, 218, 66,  211, 171, 90,
+        252, 19,  40,  99,  223, 174, 255, 51,  77,  227, 48,  220, 168, 118,
+        224, 103, 75,  105, 125, 199, 73,  82,  57,  181, 81,  149, 68,  52,
+        232, 22,  2,   216, 113, 30,  109, 163, 92,  61,  14,  8,   38,  225,
+        79,  231, 170, 240, 20,  219, 204, 150, 180, 188, 116, 190, 241, 197,
+        179, 87,  74,  147, 80,  54,  212, 16,  167, 222, 136, 213, 55,  182,
+        139, 24,  209, 251, 208, 28,  111, 89,  158, 155, 243, 107, 233, 169,
+        117, 184, 31,  39};
+    CRYPT_rc4_context s;
+    CRYPT_ArcFourSetup(&s, nullptr, 0);
+    EXPECT_EQ(0, s.x);
+    EXPECT_EQ(0, s.y);
+    for (int32_t i = 0; i < kRC4ContextPermutationLength; ++i)
+      EXPECT_EQ(kNullPermutation[i], s.m[i]) << i;
+  }
+  {
+    const uint8_t kFoobarPermutation[kRC4ContextPermutationLength] = {
+        102, 214, 39,  49,  17,  132, 244, 106, 114, 76,  183, 212, 116, 73,
+        42,  103, 128, 246, 139, 199, 31,  234, 25,  109, 48,  19,  121, 4,
+        20,  54,  134, 77,  163, 38,  61,  101, 145, 78,  215, 96,  92,  80,
+        224, 168, 243, 210, 82,  252, 113, 56,  217, 62,  218, 129, 125, 33,
+        99,  9,   153, 59,  43,  13,  206, 124, 131, 18,  213, 118, 173, 122,
+        193, 172, 177, 105, 148, 207, 186, 5,   85,  32,  68,  220, 79,  84,
+        169, 209, 150, 7,   133, 63,  147, 93,  26,  130, 60,  117, 250, 57,
+        24,  247, 200, 127, 136, 66,  112, 107, 140, 154, 70,  170, 185, 138,
+        248, 236, 88,  86,  44,  216, 241, 35,  100, 151, 156, 74,  119, 55,
+        245, 46,  227, 208, 229, 16,  249, 149, 53,  157, 201, 75,  58,  28,
+        142, 238, 182, 180, 179, 144, 12,  6,   176, 10,  90,  239, 104, 40,
+        181, 194, 137, 69,  221, 205, 165, 188, 191, 87,  1,   91,  2,   171,
+        232, 34,  162, 166, 160, 126, 225, 167, 123, 197, 223, 195, 22,  203,
+        189, 237, 37,  27,  222, 175, 23,  143, 152, 192, 21,  231, 228, 141,
+        30,  204, 158, 240, 120, 98,  89,  83,  135, 251, 81,  196, 161, 3,
+        8,   230, 52,  219, 41,  242, 36,  97,  15,  155, 65,  187, 254, 64,
+        159, 67,  211, 108, 178, 146, 202, 11,  164, 226, 184, 50,  190, 174,
+        71,  233, 235, 198, 95,  51,  110, 255, 253, 72,  115, 0,   47,  94,
+        29,  45,  14,  111};
+    CRYPT_rc4_context s;
+    const uint8_t kFooBar[] = "foobar";
+    CRYPT_ArcFourSetup(&s, kFooBar, 6);
+    EXPECT_EQ(0, s.x);
+    EXPECT_EQ(0, s.y);
+    for (int32_t i = 0; i < kRC4ContextPermutationLength; ++i)
+      EXPECT_EQ(kFoobarPermutation[i], s.m[i]) << i;
+  }
+}