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authorJoachim StroĢˆmbergson <joachim@secworks.se>2018-10-23 10:32:46 +0200
committerJoachim StroĢˆmbergson <joachim@secworks.se>2018-10-23 10:32:46 +0200
commit447efe94126531908899a0749a21766534d78965 (patch)
tree7815f70ff46d4f39f0158d8cf32473e3ddde3eec
parent6bac922a4d138363c483b55fd2027f0c660fd5e6 (diff)
Hardening the API to block writes to contol signals when core is performing operations. Also blocking access to data out when core is busy. Minor cleanup of defines. Changed init and next flags to automatically toggle back to zero.
-rw-r--r--src/rtl/chacha.v57
1 files changed, 32 insertions, 25 deletions
diff --git a/src/rtl/chacha.v b/src/rtl/chacha.v
index 8bfaba6..360ff1a 100644
--- a/src/rtl/chacha.v
+++ b/src/rtl/chacha.v
@@ -91,8 +91,10 @@ module chacha(
// Registers including update variables and write enable.
//----------------------------------------------------------------
reg init_reg;
+ reg init_new;
+
reg next_reg;
- reg ctrl_we;
+ reg next_new;
reg keylen_reg;
reg keylen_we;
@@ -188,11 +190,8 @@ module chacha(
end
else
begin
- if (ctrl_we)
- begin
- init_reg <= write_data[CTRL_INIT_BIT];
- next_reg <= write_data[CTRL_NEXT_BIT];
- end
+ init_reg <= init_new;
+ next_reg <= next_new;
if (keylen_we)
keylen_reg <= write_data[KEYLEN_BIT];
@@ -217,35 +216,42 @@ module chacha(
//----------------------------------------------------------------
always @*
begin : addr_decoder
- ctrl_we = 0;
- keylen_we = 0;
- rounds_we = 0;
- key_we = 0;
- iv_we = 0;
- data_in_we = 0;
+ init_new = 1'h0;
+ next_new = 1'h0;
+ keylen_we = 1'h0;
+ rounds_we = 1'h0;
+ key_we = 1'h0;
+ iv_we = 1'h0;
+ data_in_we = 1'h0;
tmp_read_data = 32'h0;
if (cs)
begin
if (we)
begin
- if (address == ADDR_CTRL)
- ctrl_we = 1;
+ if (core_ready)
+ begin
+ if (address == ADDR_CTRL)
+ begin
+ init_new <= write_data[CTRL_INIT_BIT];
+ next_new <= write_data[CTRL_NEXT_BIT];
+ end
- if (address == ADDR_KEYLEN)
- keylen_we = 1;
+ if (address == ADDR_KEYLEN)
+ keylen_we = 1;
- if (address == ADDR_ROUNDS)
- rounds_we = 1;
+ if (address == ADDR_ROUNDS)
+ rounds_we = 1;
- if ((address >= ADDR_KEY0) && (address <= ADDR_KEY7))
- key_we = 1;
+ if ((address >= ADDR_KEY0) && (address <= ADDR_KEY7))
+ key_we = 1;
- if ((address >= ADDR_IV0) && (address <= ADDR_IV1))
- iv_we = 1;
+ if ((address >= ADDR_IV0) && (address <= ADDR_IV1))
+ iv_we = 1;
- if ((address >= ADDR_DATA_IN0) && (address <= ADDR_DATA_IN15))
- data_in_we = 1;
+ if ((address >= ADDR_DATA_IN0) && (address <= ADDR_DATA_IN15))
+ data_in_we = 1;
+ end
end // if (we)
else
@@ -254,7 +260,8 @@ module chacha(
tmp_read_data = key_reg[address[2 : 0]];
if ((address >= ADDR_DATA_OUT0) && (address <= ADDR_DATA_OUT15))
- tmp_read_data = core_data_out[(15 - (address - ADDR_DATA_OUT0)) * 32 +: 32];
+ if (core_ready)
+ tmp_read_data = core_data_out[(15 - (address - ADDR_DATA_OUT0)) * 32 +: 32];
case (address)
ADDR_NAME0: tmp_read_data = CORE_NAME0;