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-rw-r--r--src/fastd.h1
-rw-r--r--src/linux_alg.c117
-rw-r--r--src/linux_alg.h3
-rw-r--r--src/method_aes128_gcm.c109
4 files changed, 158 insertions, 72 deletions
diff --git a/src/fastd.h b/src/fastd.h
index 80ec0d2..3981f46 100644
--- a/src/fastd.h
+++ b/src/fastd.h
@@ -216,6 +216,7 @@ struct _fastd_context {
int sock6fd;
int algfd_ghash;
+ int algfd_aesctr;
size_t eth_addr_size;
size_t n_eth_addr;
diff --git a/src/linux_alg.c b/src/linux_alg.c
index 70f4752..9591ce8 100644
--- a/src/linux_alg.c
+++ b/src/linux_alg.c
@@ -26,6 +26,7 @@
#include "linux_alg.h"
+#include <alloca.h>
#include <linux/if_alg.h>
#include <unistd.h>
@@ -38,27 +39,43 @@
void fastd_linux_alg_init(fastd_context *ctx) {
ctx->algfd_ghash = socket(AF_ALG, SOCK_SEQPACKET, 0);
if (ctx->algfd_ghash < 0)
- goto error_ghash;
+ goto ghash_done;
- struct sockaddr_alg sa_ghash = {};
- sa_ghash.salg_family = AF_ALG;
- strcpy((char*)sa_ghash.salg_type, "hash");
- strcpy((char*)sa_ghash.salg_name, "ghash");
- if (bind(ctx->algfd_ghash, (struct sockaddr*)&sa_ghash, sizeof(sa_ghash)) < 0) {
+ struct sockaddr_alg sa = {};
+ sa.salg_family = AF_ALG;
+ strcpy((char*)sa.salg_type, "hash");
+ strcpy((char*)sa.salg_name, "ghash");
+ if (bind(ctx->algfd_ghash, (struct sockaddr*)&sa, sizeof(sa)) < 0) {
close(ctx->algfd_ghash);
- goto error_ghash;
+ ctx->algfd_ghash = -1;
}
- return;
+ ghash_done:
+ if (ctx->algfd_ghash < 0)
+ pr_info(ctx, "no kernel support for GHASH was found, falling back to userspace implementation");
+
+ ctx->algfd_aesctr = socket(AF_ALG, SOCK_SEQPACKET, 0);
+ if (ctx->algfd_aesctr < 0)
+ goto aesctr_done;
- error_ghash:
- pr_info(ctx, "no kernel support for GHASH was found, falling back to userspace implementation");
- ctx->algfd_ghash = -1;
+ strcpy((char*)sa.salg_type, "skcipher");
+ strcpy((char*)sa.salg_name, "ctr(aes)");
+ if (bind(ctx->algfd_aesctr, (struct sockaddr*)&sa, sizeof(sa)) < 0) {
+ close(ctx->algfd_aesctr);
+ ctx->algfd_aesctr = -1;
+ }
+
+ aesctr_done:
+ if (ctx->algfd_aesctr < 0)
+ pr_info(ctx, "no kernel support for AES-CTR was found, falling back to userspace implementation");
}
void fastd_linux_alg_close(fastd_context *ctx) {
if (ctx->algfd_ghash >= 0)
close(ctx->algfd_ghash);
+
+ if (ctx->algfd_aesctr >= 0)
+ close(ctx->algfd_aesctr);
}
@@ -85,29 +102,73 @@ bool fastd_linux_alg_ghash(fastd_context *ctx, int fd, uint8_t out[16], const vo
if (!len)
return false;
- const uint8_t *in = data;
- const uint8_t *end = in+len;
+ if (write(fd, data, len) < 0) {
+ pr_error_errno(ctx, "fastd_linux_alg_ghash: write");
+ return false;
+ }
- while (in < end) {
- int bytes = write(fd, in, end-in);
- if (bytes < 0) {
- pr_error_errno(ctx, "fastd_linux_alg_ghash: write");
- return false;
- }
+ if (read(fd, out, 16) < 16) {
+ pr_error_errno(ctx, "fastd_linux_alg_ghash: read");
+ return false;
+ }
- in += bytes;
+ return true;
+}
+
+int fastd_linux_alg_aesctr_init(fastd_context *ctx, uint8_t *key, size_t keylen) {
+ if (ctx->algfd_aesctr < 0)
+ return -1;
+
+ if (setsockopt(ctx->algfd_aesctr, SOL_ALG, ALG_SET_KEY, key, keylen) < 0) {
+ pr_error_errno(ctx, "fastd_linux_alg_aesctr_init: setsockopt");
+ return -1;
}
- end = out+16;
+ int ret = accept(ctx->algfd_aesctr, NULL, NULL);
- while (out < end) {
- int bytes = read(fd, out, end-out);
- if (bytes < 0) {
- pr_error_errno(ctx, "fastd_linux_alg_ghash: read");
- return false;
- }
+ if (ret < 0) {
+ pr_error_errno(ctx, "fastd_linux_alg_aesctr_init: accept");
+ return -1;
+ }
+
+ return ret;
+}
+
+bool fastd_linux_alg_aesctr(fastd_context *ctx, int fd, void *out, const void *in, size_t len, const uint8_t iv[16]) {
+ if (!len)
+ return false;
+
+ struct iovec vec = { .iov_base = (void*)in, .iov_len = len };
- out += bytes;
+ static const size_t cmsglen = sizeof(struct cmsghdr)+sizeof(struct af_alg_iv)+16;
+ struct cmsghdr *cmsg = alloca(cmsglen);
+ cmsg->cmsg_len = cmsglen;
+ cmsg->cmsg_level = SOL_ALG;
+ cmsg->cmsg_type = ALG_SET_IV;
+
+ struct af_alg_iv *alg_iv = (void*)CMSG_DATA(cmsg);
+ alg_iv->ivlen = 16;
+ memcpy(alg_iv->iv, iv, 16);
+
+ struct msghdr msg = {
+ .msg_iov = &vec,
+ .msg_iovlen = 1,
+ .msg_control = cmsg,
+ .msg_controllen = cmsglen
+ };
+
+ if (sendmsg(fd, &msg, 0) < 0) {
+ pr_error_errno(ctx, "fastd_linux_alg_aesctr: sendmsg");
+ return false;
+ }
+
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ vec.iov_base = out;
+
+ if (recvmsg(fd, &msg, 0) < 0) {
+ pr_error_errno(ctx, "fastd_linux_alg_aesctr: recvmsg");
+ return false;
}
return true;
diff --git a/src/linux_alg.h b/src/linux_alg.h
index e10f23a..0099474 100644
--- a/src/linux_alg.h
+++ b/src/linux_alg.h
@@ -36,4 +36,7 @@ void fastd_linux_alg_close(fastd_context *ctx);
int fastd_linux_alg_ghash_init(fastd_context *ctx, uint8_t key[16]);
bool fastd_linux_alg_ghash(fastd_context *ctx, int fd, uint8_t out[16], const void *data, size_t len);
+int fastd_linux_alg_aesctr_init(fastd_context *ctx, uint8_t *key, size_t keylen);
+bool fastd_linux_alg_aesctr(fastd_context *ctx, int fd, void *out, const void *in, size_t len, const uint8_t iv[16]);
+
#endif /* _FASTD_LINUX_ALG_H_ */
diff --git a/src/method_aes128_gcm.c b/src/method_aes128_gcm.c
index 86203a2..ed8f026 100644
--- a/src/method_aes128_gcm.c
+++ b/src/method_aes128_gcm.c
@@ -31,6 +31,7 @@
#include <unistd.h>
+#define KEYBYTES 16
#define NONCEBYTES 7
#define BLOCKBYTES 16
#define BLOCKQWORDS (BLOCKBYTES/8)
@@ -54,6 +55,7 @@ struct _fastd_method_session_state {
struct timespec receive_last;
uint64_t receive_reorder_seen;
+ int algfd_aesctr;
int algfd_ghash;
};
@@ -92,7 +94,11 @@ static size_t method_max_packet_size(fastd_context *ctx) {
}
-static size_t method_min_head_space(fastd_context *ctx) {
+static size_t method_min_encrypt_head_space(fastd_context *ctx) {
+ return BLOCKBYTES;
+}
+
+static size_t method_min_decrypt_head_space(fastd_context *ctx) {
return 0;
}
@@ -129,10 +135,32 @@ static inline void xor_a(block_t *x, const block_t *a) {
xor(x, x, a);
}
+static inline void xor_blocks(block_t *out, const block_t *in1, const block_t *in2, size_t n_blocks) {
+ int i;
+ for (i = 0; i < n_blocks; i++)
+ xor(&out[i], &in1[i], &in2[i]);
+}
+
+static void aes128ctr(fastd_context *ctx, block_t *out, const block_t *in, size_t n_blocks, const block_t *iv, fastd_method_session_state *session) {
+ if (session->algfd_aesctr >= 0) {
+ if (fastd_linux_alg_aesctr(ctx, session->algfd_aesctr, out, in, n_blocks*BLOCKBYTES, iv->b))
+ return;
+
+ /* on error */
+ close(session->algfd_aesctr);
+ session->algfd_aesctr = -1;
+ }
+
+ block_t stream[n_blocks];
+ crypto_stream_aes128ctr_afternm((uint8_t*)stream, sizeof(stream), iv->b, session->d);
+
+ xor_blocks(out, in, stream, n_blocks);
+}
+
static fastd_method_session_state* method_session_init(fastd_context *ctx, uint8_t *secret, size_t length, bool initiator) {
int i;
- if (length < crypto_stream_aes128ctr_KEYBYTES)
+ if (length < KEYBYTES)
exit_bug(ctx, "aes128-gcm: tried to init with short secret");
fastd_method_session_state *session = malloc(sizeof(fastd_method_session_state));
@@ -144,11 +172,12 @@ static fastd_method_session_state* method_session_init(fastd_context *ctx, uint8
session->refresh_after.tv_sec += ctx->conf->key_refresh;
crypto_stream_aes128ctr_beforenm(session->d, secret);
+ session->algfd_aesctr = fastd_linux_alg_aesctr_init(ctx, secret, KEYBYTES);
- static const uint8_t zerononce[crypto_stream_aes128ctr_NONCEBYTES] = {};
+ static const block_t zeroblock = {};
block_t Hbase[4];
- crypto_stream_aes128ctr_afternm(Hbase[0].b, BLOCKBYTES, zerononce, session->d);
+ aes128ctr(ctx, &Hbase[0], &zeroblock, 1, &zeroblock, session);
block_t Rbase[4];
Rbase[0] = r;
@@ -230,12 +259,6 @@ static void mulH_a(block_t *x, fastd_method_session_state *session) {
*x = out;
}
-static inline void xor_blocks(block_t *out, const block_t *in1, const block_t *in2, size_t n_blocks) {
- int i;
- for (i = 0; i < n_blocks; i++)
- xor(&out[i], &in1[i], &in2[i]);
-}
-
static inline void put_size(block_t *out, size_t len) {
memset(out, 0, BLOCKBYTES-5);
out->b[BLOCKBYTES-5] = len >> 29;
@@ -245,7 +268,7 @@ static inline void put_size(block_t *out, size_t len) {
out->b[BLOCKBYTES-1] = len << 3;
}
-static inline void ghash(fastd_context *ctx, block_t *out, const block_t *blocks, size_t n_blocks, fastd_method_session_state *session) {
+static void ghash(fastd_context *ctx, block_t *out, const block_t *blocks, size_t n_blocks, fastd_method_session_state *session) {
if (session->algfd_ghash >= 0) {
if (fastd_linux_alg_ghash(ctx, session->algfd_ghash, out->b, blocks, n_blocks*BLOCKBYTES))
return;
@@ -265,39 +288,39 @@ static inline void ghash(fastd_context *ctx, block_t *out, const block_t *blocks
}
static bool method_encrypt(fastd_context *ctx, fastd_peer *peer, fastd_method_session_state *session, fastd_buffer *out, fastd_buffer in) {
+ fastd_buffer_pull_head(&in, BLOCKBYTES);
+ memset(in.data, 0, BLOCKBYTES);
+
size_t tail_len = ALIGN(in.len, BLOCKBYTES)-in.len;
- *out = fastd_buffer_alloc(in.len, ALIGN(NONCEBYTES+BLOCKBYTES, 8), BLOCKBYTES+tail_len);
+ *out = fastd_buffer_alloc(in.len, ALIGN(NONCEBYTES, 8), BLOCKBYTES+tail_len);
if (tail_len)
memset(in.data+in.len, 0, tail_len);
- uint8_t nonce[crypto_stream_aes128ctr_NONCEBYTES];
- memcpy(nonce, session->send_nonce, NONCEBYTES);
- memset(nonce+NONCEBYTES, 0, crypto_stream_aes128ctr_NONCEBYTES-NONCEBYTES-1);
- nonce[crypto_stream_aes128ctr_NONCEBYTES-1] = 1;
+ block_t nonce;
+ memcpy(nonce.b, session->send_nonce, NONCEBYTES);
+ memset(nonce.b+NONCEBYTES, 0, crypto_stream_aes128ctr_NONCEBYTES-NONCEBYTES-1);
+ nonce.b[crypto_stream_aes128ctr_NONCEBYTES-1] = 1;
int n_blocks = (in.len+BLOCKBYTES-1)/BLOCKBYTES;
- block_t stream[n_blocks+1];
- crypto_stream_aes128ctr_afternm((uint8_t*)stream, sizeof(stream), nonce, session->d);
-
block_t *inblocks = in.data;
block_t *outblocks = out->data;
- xor_blocks(outblocks, inblocks, stream+1, n_blocks);
+ aes128ctr(ctx, outblocks, inblocks, n_blocks, &nonce, session);
if (tail_len)
memset(out->data+out->len, 0, tail_len);
- put_size(&outblocks[n_blocks], in.len);
+ put_size(&outblocks[n_blocks], in.len-BLOCKBYTES);
- block_t *sig = outblocks-1;
- ghash(ctx, sig, outblocks, n_blocks+1, session);
- xor_a(sig, &stream[0]);
+ block_t sig;
+ ghash(ctx, &sig, outblocks+1, n_blocks, session);
+ xor_a(&outblocks[0], &sig);
fastd_buffer_free(in);
- fastd_buffer_pull_head(out, NONCEBYTES+BLOCKBYTES);
+ fastd_buffer_pull_head(out, NONCEBYTES);
memcpy(out->data, session->send_nonce, NONCEBYTES);
increment_nonce(session->send_nonce);
@@ -311,13 +334,13 @@ static bool method_decrypt(fastd_context *ctx, fastd_peer *peer, fastd_method_se
if (!method_session_is_valid(ctx, session))
return false;
- uint8_t nonce[crypto_stream_aes128ctr_NONCEBYTES];
- memcpy(nonce, in.data, NONCEBYTES);
- memset(nonce+NONCEBYTES, 0, crypto_stream_aes128ctr_NONCEBYTES-NONCEBYTES-1);
- nonce[crypto_stream_aes128ctr_NONCEBYTES-1] = 1;
+ block_t nonce;
+ memcpy(nonce.b, in.data, NONCEBYTES);
+ memset(nonce.b+NONCEBYTES, 0, crypto_stream_aes128ctr_NONCEBYTES-NONCEBYTES-1);
+ nonce.b[crypto_stream_aes128ctr_NONCEBYTES-1] = 1;
int64_t age;
- if (!is_nonce_valid(nonce, session->receive_nonce, &age))
+ if (!is_nonce_valid(nonce.b, session->receive_nonce, &age))
return false;
if (age >= 0) {
@@ -328,45 +351,43 @@ static bool method_decrypt(fastd_context *ctx, fastd_peer *peer, fastd_method_se
return false;
}
- fastd_buffer_push_head(&in, NONCEBYTES+BLOCKBYTES);
+ fastd_buffer_push_head(&in, NONCEBYTES);
size_t tail_len = ALIGN(in.len, BLOCKBYTES)-in.len;
*out = fastd_buffer_alloc(in.len, 0, tail_len);
int n_blocks = (in.len+BLOCKBYTES-1)/BLOCKBYTES;
- block_t stream[n_blocks+1];
- crypto_stream_aes128ctr_afternm((uint8_t*)stream, sizeof(stream), nonce, session->d);
-
block_t *inblocks = in.data;
block_t *outblocks = out->data;
+ aes128ctr(ctx, outblocks, inblocks, n_blocks, &nonce, session);
+
if (tail_len)
memset(in.data+in.len, 0, tail_len);
- put_size(&inblocks[n_blocks], in.len);
+ put_size(&inblocks[n_blocks], in.len-BLOCKBYTES);
block_t sig;
- ghash(ctx, &sig, inblocks, n_blocks+1, session);
- xor_a(&sig, &stream[0]);
+ ghash(ctx, &sig, inblocks+1, n_blocks, session);
- if (memcmp(&sig, inblocks-1, BLOCKBYTES) != 0) {
+ if (memcmp(&sig, &outblocks[0], BLOCKBYTES) != 0) {
fastd_buffer_free(*out);
/* restore input buffer */
- fastd_buffer_pull_head(&in, NONCEBYTES+BLOCKBYTES);
+ fastd_buffer_pull_head(&in, NONCEBYTES);
return false;
}
- xor_blocks(outblocks, inblocks, stream+1, n_blocks);
-
fastd_buffer_free(in);
+ fastd_buffer_push_head(out, BLOCKBYTES);
+
if (age < 0) {
session->receive_reorder_seen >>= age;
session->receive_reorder_seen |= (1 >> (age+1));
- memcpy(session->receive_nonce, nonce, NONCEBYTES);
+ memcpy(session->receive_nonce, nonce.b, NONCEBYTES);
session->receive_last = ctx->now;
}
else if (age == 0 || session->receive_reorder_seen & (1 << (age-1))) {
@@ -386,8 +407,8 @@ const fastd_method fastd_method_aes128_gcm = {
.name = "aes128-gcm",
.max_packet_size = method_max_packet_size,
- .min_encrypt_head_space = method_min_head_space,
- .min_decrypt_head_space = method_min_head_space,
+ .min_encrypt_head_space = method_min_encrypt_head_space,
+ .min_decrypt_head_space = method_min_decrypt_head_space,
.min_encrypt_tail_space = method_min_encrypt_tail_space,
.min_decrypt_tail_space = method_min_decrypt_tail_space,
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-14 10:50:27 +0100