Bug Summary

File:crypto/aes.c
Warning:line 864, column 6
Assigned value is garbage or undefined

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name aes.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -ffreestanding -mcmodel=kernel -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -target-feature -sse2 -target-feature -sse -target-feature -3dnow -target-feature -mmx -target-feature +save-args -disable-red-zone -no-implicit-float -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -nostdsysteminc -nobuiltininc -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/sys -I /usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -I /usr/src/sys/arch -I /usr/src/sys/dev/pci/drm/include -I /usr/src/sys/dev/pci/drm/include/uapi -I /usr/src/sys/dev/pci/drm/amd/include/asic_reg -I /usr/src/sys/dev/pci/drm/amd/include -I /usr/src/sys/dev/pci/drm/amd/amdgpu -I /usr/src/sys/dev/pci/drm/amd/display -I /usr/src/sys/dev/pci/drm/amd/display/include -I /usr/src/sys/dev/pci/drm/amd/display/dc -I /usr/src/sys/dev/pci/drm/amd/display/amdgpu_dm -I /usr/src/sys/dev/pci/drm/amd/pm/inc -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu11 -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu12 -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/hwmgr -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/smumgr -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc/hw -I /usr/src/sys/dev/pci/drm/amd/display/dc/clk_mgr -I /usr/src/sys/dev/pci/drm/amd/display/modules/inc -I /usr/src/sys/dev/pci/drm/amd/display/modules/hdcp -I /usr/src/sys/dev/pci/drm/amd/display/dmub/inc -I /usr/src/sys/dev/pci/drm/i915 -D DDB -D DIAGNOSTIC -D KTRACE -D ACCOUNTING -D KMEMSTATS -D PTRACE -D POOL_DEBUG -D CRYPTO -D SYSVMSG -D SYSVSEM -D SYSVSHM -D UVM_SWAP_ENCRYPT -D FFS -D FFS2 -D FFS_SOFTUPDATES -D UFS_DIRHASH -D QUOTA -D EXT2FS -D MFS -D NFSCLIENT -D NFSSERVER -D CD9660 -D UDF -D MSDOSFS -D FIFO -D FUSE -D SOCKET_SPLICE -D TCP_ECN -D TCP_SIGNATURE -D INET6 -D IPSEC -D PPP_BSDCOMP -D PPP_DEFLATE -D PIPEX -D MROUTING -D MPLS -D BOOT_CONFIG -D USER_PCICONF -D APERTURE -D MTRR -D NTFS -D HIBERNATE -D PCIVERBOSE -D USBVERBOSE -D WSDISPLAY_COMPAT_USL -D WSDISPLAY_COMPAT_RAWKBD -D WSDISPLAY_DEFAULTSCREENS=6 -D X86EMU -D ONEWIREVERBOSE -D MULTIPROCESSOR -D MAXUSERS=80 -D _KERNEL -D CONFIG_DRM_AMD_DC_DCN3_0 -O2 -Wno-pointer-sign -Wno-address-of-packed-member -Wno-constant-conversion -Wno-unused-but-set-variable -Wno-gnu-folding-constant -fdebug-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -o /usr/obj/sys/arch/amd64/compile/GENERIC.MP/scan-build/2022-01-12-131800-47421-1 -x c /usr/src/sys/crypto/aes.c
1/* $OpenBSD: aes.c,v 1.2 2020/07/22 13:54:30 tobhe Exp $ */
2/*
3 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
4 *
5 * Modified for OpenBSD by Thomas Pornin and Mike Belopuhov.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining
8 * a copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sublicense, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be
16 * included in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
22 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
23 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 * SOFTWARE.
26 */
27
28#include <sys/types.h>
29#include <sys/systm.h>
30#include <sys/stdint.h>
31
32#include "aes.h"
33
34static inline void
35enc32le(void *dst, uint32_t x)
36{
37 unsigned char *buf = dst;
38
39 buf[0] = (unsigned char)x;
40 buf[1] = (unsigned char)(x >> 8);
41 buf[2] = (unsigned char)(x >> 16);
42 buf[3] = (unsigned char)(x >> 24);
43}
44
45static inline uint32_t
46dec32le(const void *src)
47{
48 const unsigned char *buf = src;
49
50 return (uint32_t)buf[0]
51 | ((uint32_t)buf[1] << 8)
52 | ((uint32_t)buf[2] << 16)
53 | ((uint32_t)buf[3] << 24);
54}
55
56/*
57 * This constant-time implementation is "bitsliced": the 128-bit state is
58 * split over eight 32-bit words q* in the following way:
59 *
60 * -- Input block consists in 16 bytes:
61 * a00 a10 a20 a30 a01 a11 a21 a31 a02 a12 a22 a32 a03 a13 a23 a33
62 * In the terminology of FIPS 197, this is a 4x4 matrix which is read
63 * column by column.
64 *
65 * -- Each byte is split into eight bits which are distributed over the
66 * eight words, at the same rank. Thus, for a byte x at rank k, bit 0
67 * (least significant) of x will be at rank k in q0 (if that bit is b,
68 * then it contributes "b << k" to the value of q0), bit 1 of x will be
69 * at rank k in q1, and so on.
70 *
71 * -- Ranks given to bits are in "row order" and are either all even, or
72 * all odd. Two independent AES states are thus interleaved, one using
73 * the even ranks, the other the odd ranks. Row order means:
74 * a00 a01 a02 a03 a10 a11 a12 a13 a20 a21 a22 a23 a30 a31 a32 a33
75 *
76 * Converting input bytes from two AES blocks to bitslice representation
77 * is done in the following way:
78 * -- Decode first block into the four words q0 q2 q4 q6, in that order,
79 * using little-endian convention.
80 * -- Decode second block into the four words q1 q3 q5 q7, in that order,
81 * using little-endian convention.
82 * -- Call aes_ct_ortho().
83 *
84 * Converting back to bytes is done by using the reverse operations. Note
85 * that aes_ct_ortho() is its own inverse.
86 */
87
88/*
89 * The AES S-box, as a bitsliced constant-time version. The input array
90 * consists in eight 32-bit words; 32 S-box instances are computed in
91 * parallel. Bits 0 to 7 of each S-box input (bit 0 is least significant)
92 * are spread over the words 0 to 7, at the same rank.
93 */
94static void
95aes_ct_bitslice_Sbox(uint32_t *q)
96{
97 /*
98 * This S-box implementation is a straightforward translation of
99 * the circuit described by Boyar and Peralta in "A new
100 * combinational logic minimization technique with applications
101 * to cryptology" (https://eprint.iacr.org/2009/191.pdf).
102 *
103 * Note that variables x* (input) and s* (output) are numbered
104 * in "reverse" order (x0 is the high bit, x7 is the low bit).
105 */
106
107 uint32_t x0, x1, x2, x3, x4, x5, x6, x7;
108 uint32_t y1, y2, y3, y4, y5, y6, y7, y8, y9;
109 uint32_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19;
110 uint32_t y20, y21;
111 uint32_t z0, z1, z2, z3, z4, z5, z6, z7, z8, z9;
112 uint32_t z10, z11, z12, z13, z14, z15, z16, z17;
113 uint32_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9;
114 uint32_t t10, t11, t12, t13, t14, t15, t16, t17, t18, t19;
115 uint32_t t20, t21, t22, t23, t24, t25, t26, t27, t28, t29;
116 uint32_t t30, t31, t32, t33, t34, t35, t36, t37, t38, t39;
117 uint32_t t40, t41, t42, t43, t44, t45, t46, t47, t48, t49;
118 uint32_t t50, t51, t52, t53, t54, t55, t56, t57, t58, t59;
119 uint32_t t60, t61, t62, t63, t64, t65, t66, t67;
120 uint32_t s0, s1, s2, s3, s4, s5, s6, s7;
121
122 x0 = q[7];
123 x1 = q[6];
124 x2 = q[5];
125 x3 = q[4];
126 x4 = q[3];
127 x5 = q[2];
128 x6 = q[1];
129 x7 = q[0];
130
131 /*
132 * Top linear transformation.
133 */
134 y14 = x3 ^ x5;
135 y13 = x0 ^ x6;
136 y9 = x0 ^ x3;
137 y8 = x0 ^ x5;
138 t0 = x1 ^ x2;
139 y1 = t0 ^ x7;
140 y4 = y1 ^ x3;
141 y12 = y13 ^ y14;
142 y2 = y1 ^ x0;
143 y5 = y1 ^ x6;
144 y3 = y5 ^ y8;
145 t1 = x4 ^ y12;
146 y15 = t1 ^ x5;
147 y20 = t1 ^ x1;
148 y6 = y15 ^ x7;
149 y10 = y15 ^ t0;
150 y11 = y20 ^ y9;
151 y7 = x7 ^ y11;
152 y17 = y10 ^ y11;
153 y19 = y10 ^ y8;
154 y16 = t0 ^ y11;
155 y21 = y13 ^ y16;
156 y18 = x0 ^ y16;
157
158 /*
159 * Non-linear section.
160 */
161 t2 = y12 & y15;
162 t3 = y3 & y6;
163 t4 = t3 ^ t2;
164 t5 = y4 & x7;
165 t6 = t5 ^ t2;
166 t7 = y13 & y16;
167 t8 = y5 & y1;
168 t9 = t8 ^ t7;
169 t10 = y2 & y7;
170 t11 = t10 ^ t7;
171 t12 = y9 & y11;
172 t13 = y14 & y17;
173 t14 = t13 ^ t12;
174 t15 = y8 & y10;
175 t16 = t15 ^ t12;
176 t17 = t4 ^ t14;
177 t18 = t6 ^ t16;
178 t19 = t9 ^ t14;
179 t20 = t11 ^ t16;
180 t21 = t17 ^ y20;
181 t22 = t18 ^ y19;
182 t23 = t19 ^ y21;
183 t24 = t20 ^ y18;
184
185 t25 = t21 ^ t22;
186 t26 = t21 & t23;
187 t27 = t24 ^ t26;
188 t28 = t25 & t27;
189 t29 = t28 ^ t22;
190 t30 = t23 ^ t24;
191 t31 = t22 ^ t26;
192 t32 = t31 & t30;
193 t33 = t32 ^ t24;
194 t34 = t23 ^ t33;
195 t35 = t27 ^ t33;
196 t36 = t24 & t35;
197 t37 = t36 ^ t34;
198 t38 = t27 ^ t36;
199 t39 = t29 & t38;
200 t40 = t25 ^ t39;
201
202 t41 = t40 ^ t37;
203 t42 = t29 ^ t33;
204 t43 = t29 ^ t40;
205 t44 = t33 ^ t37;
206 t45 = t42 ^ t41;
207 z0 = t44 & y15;
208 z1 = t37 & y6;
209 z2 = t33 & x7;
210 z3 = t43 & y16;
211 z4 = t40 & y1;
212 z5 = t29 & y7;
213 z6 = t42 & y11;
214 z7 = t45 & y17;
215 z8 = t41 & y10;
216 z9 = t44 & y12;
217 z10 = t37 & y3;
218 z11 = t33 & y4;
219 z12 = t43 & y13;
220 z13 = t40 & y5;
221 z14 = t29 & y2;
222 z15 = t42 & y9;
223 z16 = t45 & y14;
224 z17 = t41 & y8;
225
226 /*
227 * Bottom linear transformation.
228 */
229 t46 = z15 ^ z16;
230 t47 = z10 ^ z11;
231 t48 = z5 ^ z13;
232 t49 = z9 ^ z10;
233 t50 = z2 ^ z12;
234 t51 = z2 ^ z5;
235 t52 = z7 ^ z8;
236 t53 = z0 ^ z3;
237 t54 = z6 ^ z7;
238 t55 = z16 ^ z17;
239 t56 = z12 ^ t48;
240 t57 = t50 ^ t53;
241 t58 = z4 ^ t46;
242 t59 = z3 ^ t54;
243 t60 = t46 ^ t57;
244 t61 = z14 ^ t57;
245 t62 = t52 ^ t58;
246 t63 = t49 ^ t58;
247 t64 = z4 ^ t59;
248 t65 = t61 ^ t62;
249 t66 = z1 ^ t63;
250 s0 = t59 ^ t63;
251 s6 = t56 ^ ~t62;
252 s7 = t48 ^ ~t60;
253 t67 = t64 ^ t65;
254 s3 = t53 ^ t66;
255 s4 = t51 ^ t66;
256 s5 = t47 ^ t65;
257 s1 = t64 ^ ~s3;
258 s2 = t55 ^ ~t67;
259
260 q[7] = s0;
261 q[6] = s1;
262 q[5] = s2;
263 q[4] = s3;
264 q[3] = s4;
265 q[2] = s5;
266 q[1] = s6;
267 q[0] = s7;
268}
269
270/*
271 * Perform bytewise orthogonalization of eight 32-bit words. Bytes
272 * of q0..q7 are spread over all words: for a byte x that occurs
273 * at rank i in q[j] (byte x uses bits 8*i to 8*i+7 in q[j]), the bit
274 * of rank k in x (0 <= k <= 7) goes to q[k] at rank 8*i+j.
275 *
276 * This operation is an involution.
277 */
278static void
279aes_ct_ortho(uint32_t *q)
280{
281#define SWAPN(cl, ch, s, x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)cl) | ((b & (uint32_t)cl) << (s)); (y) = ((a &
(uint32_t)ch) >> (s)) | (b & (uint32_t)ch); } while
(0) do { \
282 uint32_t a, b; \
283 a = (x); \
284 b = (y); \
285 (x) = (a & (uint32_t)cl) | ((b & (uint32_t)cl) << (s)); \
286 (y) = ((a & (uint32_t)ch) >> (s)) | (b & (uint32_t)ch); \
287 } while (0)
288
289#define SWAP2(x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x55555555) | ((b & (uint32_t)0x55555555) << (1));
(y) = ((a & (uint32_t)0xAAAAAAAA) >> (1)) | (b &
(uint32_t)0xAAAAAAAA); } while (0) SWAPN(0x55555555, 0xAAAAAAAA, 1, x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x55555555) | ((b & (uint32_t)0x55555555) << (1));
(y) = ((a & (uint32_t)0xAAAAAAAA) >> (1)) | (b &
(uint32_t)0xAAAAAAAA); } while (0)
290#define SWAP4(x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x33333333) | ((b & (uint32_t)0x33333333) << (2));
(y) = ((a & (uint32_t)0xCCCCCCCC) >> (2)) | (b &
(uint32_t)0xCCCCCCCC); } while (0) SWAPN(0x33333333, 0xCCCCCCCC, 2, x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x33333333) | ((b & (uint32_t)0x33333333) << (2));
(y) = ((a & (uint32_t)0xCCCCCCCC) >> (2)) | (b &
(uint32_t)0xCCCCCCCC); } while (0)
291#define SWAP8(x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) << (4));
(y) = ((a & (uint32_t)0xF0F0F0F0) >> (4)) | (b &
(uint32_t)0xF0F0F0F0); } while (0) SWAPN(0x0F0F0F0F, 0xF0F0F0F0, 4, x, y)do { uint32_t a, b; a = (x); b = (y); (x) = (a & (uint32_t
)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) << (4));
(y) = ((a & (uint32_t)0xF0F0F0F0) >> (4)) | (b &
(uint32_t)0xF0F0F0F0); } while (0)
292
293 SWAP2(q[0], q[1])do { uint32_t a, b; a = (q[0]); b = (q[1]); (q[0]) = (a &
(uint32_t)0x55555555) | ((b & (uint32_t)0x55555555) <<
(1)); (q[1]) = ((a & (uint32_t)0xAAAAAAAA) >> (1))
| (b & (uint32_t)0xAAAAAAAA); } while (0);
294 SWAP2(q[2], q[3])do { uint32_t a, b; a = (q[2]); b = (q[3]); (q[2]) = (a &
(uint32_t)0x55555555) | ((b & (uint32_t)0x55555555) <<
(1)); (q[3]) = ((a & (uint32_t)0xAAAAAAAA) >> (1))
| (b & (uint32_t)0xAAAAAAAA); } while (0);
295 SWAP2(q[4], q[5])do { uint32_t a, b; a = (q[4]); b = (q[5]); (q[4]) = (a &
(uint32_t)0x55555555) | ((b & (uint32_t)0x55555555) <<
(1)); (q[5]) = ((a & (uint32_t)0xAAAAAAAA) >> (1))
| (b & (uint32_t)0xAAAAAAAA); } while (0);
296 SWAP2(q[6], q[7])do { uint32_t a, b; a = (q[6]); b = (q[7]); (q[6]) = (a &
(uint32_t)0x55555555) | ((b & (uint32_t)0x55555555) <<
(1)); (q[7]) = ((a & (uint32_t)0xAAAAAAAA) >> (1))
| (b & (uint32_t)0xAAAAAAAA); } while (0);
297
298 SWAP4(q[0], q[2])do { uint32_t a, b; a = (q[0]); b = (q[2]); (q[0]) = (a &
(uint32_t)0x33333333) | ((b & (uint32_t)0x33333333) <<
(2)); (q[2]) = ((a & (uint32_t)0xCCCCCCCC) >> (2))
| (b & (uint32_t)0xCCCCCCCC); } while (0);
299 SWAP4(q[1], q[3])do { uint32_t a, b; a = (q[1]); b = (q[3]); (q[1]) = (a &
(uint32_t)0x33333333) | ((b & (uint32_t)0x33333333) <<
(2)); (q[3]) = ((a & (uint32_t)0xCCCCCCCC) >> (2))
| (b & (uint32_t)0xCCCCCCCC); } while (0);
300 SWAP4(q[4], q[6])do { uint32_t a, b; a = (q[4]); b = (q[6]); (q[4]) = (a &
(uint32_t)0x33333333) | ((b & (uint32_t)0x33333333) <<
(2)); (q[6]) = ((a & (uint32_t)0xCCCCCCCC) >> (2))
| (b & (uint32_t)0xCCCCCCCC); } while (0);
301 SWAP4(q[5], q[7])do { uint32_t a, b; a = (q[5]); b = (q[7]); (q[5]) = (a &
(uint32_t)0x33333333) | ((b & (uint32_t)0x33333333) <<
(2)); (q[7]) = ((a & (uint32_t)0xCCCCCCCC) >> (2))
| (b & (uint32_t)0xCCCCCCCC); } while (0);
302
303 SWAP8(q[0], q[4])do { uint32_t a, b; a = (q[0]); b = (q[4]); (q[0]) = (a &
(uint32_t)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) <<
(4)); (q[4]) = ((a & (uint32_t)0xF0F0F0F0) >> (4))
| (b & (uint32_t)0xF0F0F0F0); } while (0);
304 SWAP8(q[1], q[5])do { uint32_t a, b; a = (q[1]); b = (q[5]); (q[1]) = (a &
(uint32_t)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) <<
(4)); (q[5]) = ((a & (uint32_t)0xF0F0F0F0) >> (4))
| (b & (uint32_t)0xF0F0F0F0); } while (0);
305 SWAP8(q[2], q[6])do { uint32_t a, b; a = (q[2]); b = (q[6]); (q[2]) = (a &
(uint32_t)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) <<
(4)); (q[6]) = ((a & (uint32_t)0xF0F0F0F0) >> (4))
| (b & (uint32_t)0xF0F0F0F0); } while (0);
306 SWAP8(q[3], q[7])do { uint32_t a, b; a = (q[3]); b = (q[7]); (q[3]) = (a &
(uint32_t)0x0F0F0F0F) | ((b & (uint32_t)0x0F0F0F0F) <<
(4)); (q[7]) = ((a & (uint32_t)0xF0F0F0F0) >> (4))
| (b & (uint32_t)0xF0F0F0F0); } while (0);
307}
308
309static inline uint32_t
310sub_word(uint32_t x)
311{
312 uint32_t q[8];
313 int i;
314
315 for (i = 0; i < 8; i ++) {
316 q[i] = x;
317 }
318 aes_ct_ortho(q);
319 aes_ct_bitslice_Sbox(q);
320 aes_ct_ortho(q);
321 return q[0];
322}
323
324static const unsigned char Rcon[] = {
325 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36
326};
327
328/*
329 * Base key schedule code. The function sub_word() must be defined
330 * below. Subkeys are produced in little-endian convention (but not
331 * bitsliced). Key length is expressed in bytes.
332 */
333static unsigned
334aes_keysched_base(uint32_t *skey, const void *key, size_t key_len)
335{
336 unsigned num_rounds;
337 int i, j, k, nk, nkf;
338 uint32_t tmp;
339
340 switch (key_len) {
341 case 16:
342 num_rounds = 10;
343 break;
344 case 24:
345 num_rounds = 12;
346 break;
347 case 32:
348 num_rounds = 14;
349 break;
350 default:
351 return 0;
352 }
353 nk = (int)(key_len >> 2);
354 nkf = (int)((num_rounds + 1) << 2);
355 for (i = 0; i < nk; i ++) {
356 tmp = dec32le((const unsigned char *)key + (i << 2));
357 skey[i] = tmp;
358 }
359 tmp = skey[(key_len >> 2) - 1];
360 for (i = nk, j = 0, k = 0; i < nkf; i ++) {
361 if (j == 0) {
362 tmp = (tmp << 24) | (tmp >> 8);
363 tmp = sub_word(tmp) ^ Rcon[k];
364 } else if (nk > 6 && j == 4) {
365 tmp = sub_word(tmp);
366 }
367 tmp ^= skey[i - nk];
368 skey[i] = tmp;
369 if (++ j == nk) {
370 j = 0;
371 k ++;
372 }
373 }
374 return num_rounds;
375}
376
377/*
378 * AES key schedule, constant-time version. skey[] is filled with n+1
379 * 128-bit subkeys, where n is the number of rounds (10 to 14, depending
380 * on key size). The number of rounds is returned. If the key size is
381 * invalid (not 16, 24 or 32), then 0 is returned.
382 */
383unsigned
384aes_ct_keysched(uint32_t *comp_skey, const void *key, size_t key_len)
385{
386 uint32_t skey[60];
387 unsigned u, num_rounds;
388
389 num_rounds = aes_keysched_base(skey, key, key_len);
390 for (u = 0; u <= num_rounds; u ++) {
391 uint32_t q[8];
392
393 q[0] = q[1] = skey[(u << 2) + 0];
394 q[2] = q[3] = skey[(u << 2) + 1];
395 q[4] = q[5] = skey[(u << 2) + 2];
396 q[6] = q[7] = skey[(u << 2) + 3];
397 aes_ct_ortho(q);
398 comp_skey[(u << 2) + 0] =
399 (q[0] & 0x55555555) | (q[1] & 0xAAAAAAAA);
400 comp_skey[(u << 2) + 1] =
401 (q[2] & 0x55555555) | (q[3] & 0xAAAAAAAA);
402 comp_skey[(u << 2) + 2] =
403 (q[4] & 0x55555555) | (q[5] & 0xAAAAAAAA);
404 comp_skey[(u << 2) + 3] =
405 (q[6] & 0x55555555) | (q[7] & 0xAAAAAAAA);
406 }
407 return num_rounds;
408}
409
410/*
411 * Expand AES subkeys as produced by aes_ct_keysched(), into
412 * a larger array suitable for aes_ct_bitslice_encrypt() and
413 * aes_ct_bitslice_decrypt().
414 */
415void
416aes_ct_skey_expand(uint32_t *skey,
417 unsigned num_rounds, const uint32_t *comp_skey)
418{
419 unsigned u, v, n;
420
421 n = (num_rounds + 1) << 2;
422 for (u = 0, v = 0; u < n; u ++, v += 2) {
423 uint32_t x, y;
424
425 x = y = comp_skey[u];
426 x &= 0x55555555;
427 skey[v + 0] = x | (x << 1);
428 y &= 0xAAAAAAAA;
429 skey[v + 1] = y | (y >> 1);
430 }
431}
432
433static inline void
434add_round_key(uint32_t *q, const uint32_t *sk)
435{
436 q[0] ^= sk[0];
437 q[1] ^= sk[1];
438 q[2] ^= sk[2];
439 q[3] ^= sk[3];
440 q[4] ^= sk[4];
441 q[5] ^= sk[5];
442 q[6] ^= sk[6];
443 q[7] ^= sk[7];
444}
445
446static inline void
447shift_rows(uint32_t *q)
448{
449 int i;
450
451 for (i = 0; i < 8; i ++) {
452 uint32_t x;
453
454 x = q[i];
455 q[i] = (x & 0x000000FF)
456 | ((x & 0x0000FC00) >> 2) | ((x & 0x00000300) << 6)
457 | ((x & 0x00F00000) >> 4) | ((x & 0x000F0000) << 4)
458 | ((x & 0xC0000000) >> 6) | ((x & 0x3F000000) << 2);
459 }
460}
461
462static inline uint32_t
463rotr16(uint32_t x)
464{
465 return (x << 16) | (x >> 16);
466}
467
468static inline void
469mix_columns(uint32_t *q)
470{
471 uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
472 uint32_t r0, r1, r2, r3, r4, r5, r6, r7;
473
474 q0 = q[0];
475 q1 = q[1];
476 q2 = q[2];
477 q3 = q[3];
478 q4 = q[4];
479 q5 = q[5];
480 q6 = q[6];
481 q7 = q[7];
482 r0 = (q0 >> 8) | (q0 << 24);
483 r1 = (q1 >> 8) | (q1 << 24);
484 r2 = (q2 >> 8) | (q2 << 24);
485 r3 = (q3 >> 8) | (q3 << 24);
486 r4 = (q4 >> 8) | (q4 << 24);
487 r5 = (q5 >> 8) | (q5 << 24);
488 r6 = (q6 >> 8) | (q6 << 24);
489 r7 = (q7 >> 8) | (q7 << 24);
490
491 q[0] = q7 ^ r7 ^ r0 ^ rotr16(q0 ^ r0);
492 q[1] = q0 ^ r0 ^ q7 ^ r7 ^ r1 ^ rotr16(q1 ^ r1);
493 q[2] = q1 ^ r1 ^ r2 ^ rotr16(q2 ^ r2);
494 q[3] = q2 ^ r2 ^ q7 ^ r7 ^ r3 ^ rotr16(q3 ^ r3);
495 q[4] = q3 ^ r3 ^ q7 ^ r7 ^ r4 ^ rotr16(q4 ^ r4);
496 q[5] = q4 ^ r4 ^ r5 ^ rotr16(q5 ^ r5);
497 q[6] = q5 ^ r5 ^ r6 ^ rotr16(q6 ^ r6);
498 q[7] = q6 ^ r6 ^ r7 ^ rotr16(q7 ^ r7);
499}
500
501/*
502 * Compute AES encryption on bitsliced data. Since input is stored on
503 * eight 32-bit words, two block encryptions are actually performed
504 * in parallel.
505 */
506void
507aes_ct_bitslice_encrypt(unsigned num_rounds,
508 const uint32_t *skey, uint32_t *q)
509{
510 unsigned u;
511
512 add_round_key(q, skey);
513 for (u = 1; u < num_rounds; u ++) {
514 aes_ct_bitslice_Sbox(q);
515 shift_rows(q);
516 mix_columns(q);
517 add_round_key(q, skey + (u << 3));
518 }
519 aes_ct_bitslice_Sbox(q);
520 shift_rows(q);
521 add_round_key(q, skey + (num_rounds << 3));
522}
523
524/*
525 * Like aes_ct_bitslice_Sbox(), but for the inverse S-box.
526 */
527void
528aes_ct_bitslice_invSbox(uint32_t *q)
529{
530 /*
531 * AES S-box is:
532 * S(x) = A(I(x)) ^ 0x63
533 * where I() is inversion in GF(256), and A() is a linear
534 * transform (0 is formally defined to be its own inverse).
535 * Since inversion is an involution, the inverse S-box can be
536 * computed from the S-box as:
537 * iS(x) = B(S(B(x ^ 0x63)) ^ 0x63)
538 * where B() is the inverse of A(). Indeed, for any y in GF(256):
539 * iS(S(y)) = B(A(I(B(A(I(y)) ^ 0x63 ^ 0x63))) ^ 0x63 ^ 0x63) = y
540 *
541 * Note: we reuse the implementation of the forward S-box,
542 * instead of duplicating it here, so that total code size is
543 * lower. By merging the B() transforms into the S-box circuit
544 * we could make faster CBC decryption, but CBC decryption is
545 * already quite faster than CBC encryption because we can
546 * process two blocks in parallel.
547 */
548 uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
549
550 q0 = ~q[0];
551 q1 = ~q[1];
552 q2 = q[2];
553 q3 = q[3];
554 q4 = q[4];
555 q5 = ~q[5];
556 q6 = ~q[6];
557 q7 = q[7];
558 q[7] = q1 ^ q4 ^ q6;
559 q[6] = q0 ^ q3 ^ q5;
560 q[5] = q7 ^ q2 ^ q4;
561 q[4] = q6 ^ q1 ^ q3;
562 q[3] = q5 ^ q0 ^ q2;
563 q[2] = q4 ^ q7 ^ q1;
564 q[1] = q3 ^ q6 ^ q0;
565 q[0] = q2 ^ q5 ^ q7;
566
567 aes_ct_bitslice_Sbox(q);
568
569 q0 = ~q[0];
570 q1 = ~q[1];
571 q2 = q[2];
572 q3 = q[3];
573 q4 = q[4];
574 q5 = ~q[5];
575 q6 = ~q[6];
576 q7 = q[7];
577 q[7] = q1 ^ q4 ^ q6;
578 q[6] = q0 ^ q3 ^ q5;
579 q[5] = q7 ^ q2 ^ q4;
580 q[4] = q6 ^ q1 ^ q3;
581 q[3] = q5 ^ q0 ^ q2;
582 q[2] = q4 ^ q7 ^ q1;
583 q[1] = q3 ^ q6 ^ q0;
584 q[0] = q2 ^ q5 ^ q7;
585}
586
587static inline void
588inv_shift_rows(uint32_t *q)
589{
590 int i;
591
592 for (i = 0; i < 8; i ++) {
593 uint32_t x;
594
595 x = q[i];
596 q[i] = (x & 0x000000FF)
597 | ((x & 0x00003F00) << 2) | ((x & 0x0000C000) >> 6)
598 | ((x & 0x000F0000) << 4) | ((x & 0x00F00000) >> 4)
599 | ((x & 0x03000000) << 6) | ((x & 0xFC000000) >> 2);
600 }
601}
602
603static void
604inv_mix_columns(uint32_t *q)
605{
606 uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
607 uint32_t r0, r1, r2, r3, r4, r5, r6, r7;
608
609 q0 = q[0];
610 q1 = q[1];
611 q2 = q[2];
612 q3 = q[3];
613 q4 = q[4];
614 q5 = q[5];
615 q6 = q[6];
616 q7 = q[7];
617 r0 = (q0 >> 8) | (q0 << 24);
618 r1 = (q1 >> 8) | (q1 << 24);
619 r2 = (q2 >> 8) | (q2 << 24);
620 r3 = (q3 >> 8) | (q3 << 24);
621 r4 = (q4 >> 8) | (q4 << 24);
622 r5 = (q5 >> 8) | (q5 << 24);
623 r6 = (q6 >> 8) | (q6 << 24);
624 r7 = (q7 >> 8) | (q7 << 24);
625
626 q[0] = q5 ^ q6 ^ q7 ^ r0 ^ r5 ^ r7 ^ rotr16(q0 ^ q5 ^ q6 ^ r0 ^ r5);
627 q[1] = q0 ^ q5 ^ r0 ^ r1 ^ r5 ^ r6 ^ r7 ^ rotr16(q1 ^ q5 ^ q7 ^ r1 ^ r5 ^ r6);
628 q[2] = q0 ^ q1 ^ q6 ^ r1 ^ r2 ^ r6 ^ r7 ^ rotr16(q0 ^ q2 ^ q6 ^ r2 ^ r6 ^ r7);
629 q[3] = q0 ^ q1 ^ q2 ^ q5 ^ q6 ^ r0 ^ r2 ^ r3 ^ r5 ^ rotr16(q0 ^ q1 ^ q3 ^ q5 ^ q6 ^ q7 ^ r0 ^ r3 ^ r5 ^ r7);
630 q[4] = q1 ^ q2 ^ q3 ^ q5 ^ r1 ^ r3 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr16(q1 ^ q2 ^ q4 ^ q5 ^ q7 ^ r1 ^ r4 ^ r5 ^ r6);
631 q[5] = q2 ^ q3 ^ q4 ^ q6 ^ r2 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr16(q2 ^ q3 ^ q5 ^ q6 ^ r2 ^ r5 ^ r6 ^ r7);
632 q[6] = q3 ^ q4 ^ q5 ^ q7 ^ r3 ^ r5 ^ r6 ^ r7 ^ rotr16(q3 ^ q4 ^ q6 ^ q7 ^ r3 ^ r6 ^ r7);
633 q[7] = q4 ^ q5 ^ q6 ^ r4 ^ r6 ^ r7 ^ rotr16(q4 ^ q5 ^ q7 ^ r4 ^ r7);
634}
635
636/*
637 * Compute AES decryption on bitsliced data. Since input is stored on
638 * eight 32-bit words, two block decryptions are actually performed
639 * in parallel.
640 */
641void
642aes_ct_bitslice_decrypt(unsigned num_rounds,
643 const uint32_t *skey, uint32_t *q)
644{
645 unsigned u;
646
647 add_round_key(q, skey + (num_rounds << 3));
648 for (u = num_rounds - 1; u > 0; u --) {
649 inv_shift_rows(q);
650 aes_ct_bitslice_invSbox(q);
651 add_round_key(q, skey + (u << 3));
652 inv_mix_columns(q);
653 }
654 inv_shift_rows(q);
655 aes_ct_bitslice_invSbox(q);
656 add_round_key(q, skey);
657}
658
659
660int
661AES_Setkey(AES_CTX *ctx, const uint8_t *key, int len)
662{
663 ctx->num_rounds = aes_ct_keysched(ctx->sk, key, len);
664 if (ctx->num_rounds == 0)
665 return -1;
666 aes_ct_skey_expand(ctx->sk_exp, ctx->num_rounds, ctx->sk);
667 return 0;
668}
669
670void
671AES_Encrypt_ECB(AES_CTX *ctx, const uint8_t *src,
672 uint8_t *dst, size_t num_blocks)
673{
674 while (num_blocks > 0) {
675 uint32_t q[8];
676
677 q[0] = dec32le(src);
678 q[2] = dec32le(src + 4);
679 q[4] = dec32le(src + 8);
680 q[6] = dec32le(src + 12);
681 if (num_blocks > 1) {
682 q[1] = dec32le(src + 16);
683 q[3] = dec32le(src + 20);
684 q[5] = dec32le(src + 24);
685 q[7] = dec32le(src + 28);
686 } else {
687 q[1] = 0;
688 q[3] = 0;
689 q[5] = 0;
690 q[7] = 0;
691 }
692 aes_ct_ortho(q);
693 aes_ct_bitslice_encrypt(ctx->num_rounds, ctx->sk_exp, q);
694 aes_ct_ortho(q);
695 enc32le(dst, q[0]);
696 enc32le(dst + 4, q[2]);
697 enc32le(dst + 8, q[4]);
698 enc32le(dst + 12, q[6]);
699 if (num_blocks > 1) {
700 enc32le(dst + 16, q[1]);
701 enc32le(dst + 20, q[3]);
702 enc32le(dst + 24, q[5]);
703 enc32le(dst + 28, q[7]);
704 src += 32;
705 dst += 32;
706 num_blocks -= 2;
707 } else {
708 break;
709 }
710 }
711}
712
713void
714AES_Decrypt_ECB(AES_CTX *ctx, const uint8_t *src,
715 uint8_t *dst, size_t num_blocks)
716{
717 while (num_blocks > 0) {
718 uint32_t q[8];
719
720 q[0] = dec32le(src);
721 q[2] = dec32le(src + 4);
722 q[4] = dec32le(src + 8);
723 q[6] = dec32le(src + 12);
724 if (num_blocks > 1) {
725 q[1] = dec32le(src + 16);
726 q[3] = dec32le(src + 20);
727 q[5] = dec32le(src + 24);
728 q[7] = dec32le(src + 28);
729 } else {
730 q[1] = 0;
731 q[3] = 0;
732 q[5] = 0;
733 q[7] = 0;
734 }
735 aes_ct_ortho(q);
736 aes_ct_bitslice_decrypt(ctx->num_rounds, ctx->sk_exp, q);
737 aes_ct_ortho(q);
738 enc32le(dst, q[0]);
739 enc32le(dst + 4, q[2]);
740 enc32le(dst + 8, q[4]);
741 enc32le(dst + 12, q[6]);
742 if (num_blocks > 1) {
743 enc32le(dst + 16, q[1]);
744 enc32le(dst + 20, q[3]);
745 enc32le(dst + 24, q[5]);
746 enc32le(dst + 28, q[7]);
747 src += 32;
748 dst += 32;
749 num_blocks -= 2;
750 } else {
751 break;
752 }
753 }
754}
755
756void
757AES_Encrypt(AES_CTX *ctx, const uint8_t *src, uint8_t *dst)
758{
759 AES_Encrypt_ECB(ctx, src, dst, 1);
760}
761
762void
763AES_Decrypt(AES_CTX *ctx, const uint8_t *src, uint8_t *dst)
764{
765 AES_Decrypt_ECB(ctx, src, dst, 1);
766}
767
768int
769AES_KeySetup_Encrypt(uint32_t *skey, const uint8_t *key, int len)
770{
771 unsigned r, u;
772 uint32_t tkey[60];
773
774 r = aes_keysched_base(tkey, key, len);
775 if (r == 0) {
2
←
Assuming 'r' is not equal to 0
→
3
←
Taking false branch
→
776 return 0;
777 }
778 for (u = 0; u < ((r + 1) << 2); u ++) {
4
←
Assuming the condition is false
→
5
←
Loop condition is false. Execution continues on line 787
→
779 uint32_t w;
780
781 w = tkey[u];
782 skey[u] = (w << 24)
783 | ((w & 0x0000FF00) << 8)
784 | ((w & 0x00FF0000) >> 8)
785 | (w >> 24);
786 }
787 return r;
788}
789
790/*
791 * Reduce value x modulo polynomial x^8+x^4+x^3+x+1. This works as
792 * long as x fits on 12 bits at most.
793 */
794static inline uint32_t
795redgf256(uint32_t x)
796{
797 uint32_t h;
798
799 h = x >> 8;
800 return (x ^ h ^ (h << 1) ^ (h << 3) ^ (h << 4)) & 0xFF;
801}
802
803/*
804 * Multiplication by 0x09 in GF(256).
805 */
806static inline uint32_t
807mul9(uint32_t x)
808{
809 return redgf256(x ^ (x << 3));
810}
811
812/*
813 * Multiplication by 0x0B in GF(256).
814 */
815static inline uint32_t
816mulb(uint32_t x)
817{
818 return redgf256(x ^ (x << 1) ^ (x << 3));
819}
820
821/*
822 * Multiplication by 0x0D in GF(256).
823 */
824static inline uint32_t
825muld(uint32_t x)
826{
827 return redgf256(x ^ (x << 2) ^ (x << 3));
828}
829
830/*
831 * Multiplication by 0x0E in GF(256).
832 */
833static inline uint32_t
834mule(uint32_t x)
835{
836 return redgf256((x << 1) ^ (x << 2) ^ (x << 3));
837}
838
839int
840AES_KeySetup_Decrypt(uint32_t *skey, const uint8_t *key, int len)
841{
842 unsigned r, u;
843 uint32_t tkey[60];
844
845 /*
846 * Compute encryption subkeys. We get them in big-endian
847 * notation.
848 */
849 r = AES_KeySetup_Encrypt(tkey, key, len);
1
Calling 'AES_KeySetup_Encrypt'
→
6
←
Returning from 'AES_KeySetup_Encrypt'
→
850 if (r
6.1
'r' is not equal to 0
 == 0) {
7
←
Taking false branch
→
851 return 0;
852 }
853
854 /*
855 * Copy the subkeys in reverse order. Also, apply InvMixColumns()
856 * on the subkeys (except first and last).
857 */
858 memcpy(skey + (r << 2), tkey, 4 * sizeof(uint32_t))__builtin_memcpy((skey + (r << 2)), (tkey), (4 * sizeof
(uint32_t)));
859 memcpy(skey, tkey + (r << 2), 4 * sizeof(uint32_t))__builtin_memcpy((skey), (tkey + (r << 2)), (4 * sizeof
(uint32_t)));
860 for (u = 4; u < (r << 2); u ++) {
8
←
The value 4 is assigned to 'u'
→
9
←
Assuming the condition is true
→
10
←
Loop condition is true. Entering loop body
→
861 uint32_t sk, sk0, sk1, sk2, sk3;
862 uint32_t tk, tk0, tk1, tk2, tk3;
863
864 sk = tkey[u];
11
←
Assigned value is garbage or undefined
865 sk0 = sk >> 24;
866 sk1 = (sk >> 16) & 0xFF;
867 sk2 = (sk >> 8) & 0xFF;
868 sk3 = sk & 0xFF;
869 tk0 = mule(sk0) ^ mulb(sk1) ^ muld(sk2) ^ mul9(sk3);
870 tk1 = mul9(sk0) ^ mule(sk1) ^ mulb(sk2) ^ muld(sk3);
871 tk2 = muld(sk0) ^ mul9(sk1) ^ mule(sk2) ^ mulb(sk3);
872 tk3 = mulb(sk0) ^ muld(sk1) ^ mul9(sk2) ^ mule(sk3);
873 tk = (tk0 << 24) ^ (tk1 << 16) ^ (tk2 << 8) ^ tk3;
874 skey[((r - (u >> 2)) << 2) + (u & 3)] = tk;
875 }
876
877 return r;
878}