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authorYawning Angel <yawning@schwanenlied.me>2023-04-08 09:57:47 +0900
committerYawning Angel <yawning@schwanenlied.me>2023-04-08 09:57:47 +0900
commitd72db2698bdb7b976bfdee075088d6ec697dafd9 (patch)
treec4168c8bf439b0d8ff9eeac89992894f5d0a72e6
parentf863264af6ef1546d3965a8bf865e14c01146054 (diff)
core/crypto/_fiat: Hedge against LLVM cleverness
Recent LLVM is getting smart to the point where the optimizer can change a traditional constant-time conditional swap into a pointer swap. Ensure that this does not happen by force-disabling optimization. Additionally, disable inlining the relevant routines such that manual inspection in optimized builds is still reasonably easy to do.
-rw-r--r--core/crypto/_fiat/fiat.odin6
-rw-r--r--core/crypto/_fiat/field_curve25519/field51.odin6
-rw-r--r--core/crypto/_fiat/field_poly1305/field4344.odin6
3 files changed, 12 insertions, 6 deletions
diff --git a/core/crypto/_fiat/fiat.odin b/core/crypto/_fiat/fiat.odin
index ae9727149..f0551722f 100644
--- a/core/crypto/_fiat/fiat.odin
+++ b/core/crypto/_fiat/fiat.odin
@@ -9,14 +9,16 @@ package fiat
u1 :: distinct u8
i1 :: distinct i8
-cmovznz_u64 :: #force_inline proc "contextless" (arg1: u1, arg2, arg3: u64) -> (out1: u64) {
+@(optimization_mode="none")
+cmovznz_u64 :: proc "contextless" (arg1: u1, arg2, arg3: u64) -> (out1: u64) {
x1 := (u64(arg1) * 0xffffffffffffffff)
x2 := ((x1 & arg3) | ((~x1) & arg2))
out1 = x2
return
}
-cmovznz_u32 :: #force_inline proc "contextless" (arg1: u1, arg2, arg3: u32) -> (out1: u32) {
+@(optimization_mode="none")
+cmovznz_u32 :: proc "contextless" (arg1: u1, arg2, arg3: u32) -> (out1: u32) {
x1 := (u32(arg1) * 0xffffffff)
x2 := ((x1 & arg3) | ((~x1) & arg2))
out1 = x2
diff --git a/core/crypto/_fiat/field_curve25519/field51.odin b/core/crypto/_fiat/field_curve25519/field51.odin
index e4ca98b57..0be94eb51 100644
--- a/core/crypto/_fiat/field_curve25519/field51.odin
+++ b/core/crypto/_fiat/field_curve25519/field51.odin
@@ -305,7 +305,8 @@ fe_opp :: proc "contextless" (out1: ^Loose_Field_Element, arg1: ^Tight_Field_Ele
out1[4] = x5
}
-fe_cond_assign :: proc "contextless" (out1, arg1: ^Tight_Field_Element, arg2: int) {
+@(optimization_mode="none")
+fe_cond_assign :: #force_no_inline proc "contextless" (out1, arg1: ^Tight_Field_Element, arg2: int) {
x1 := fiat.cmovznz_u64(fiat.u1(arg2), out1[0], arg1[0])
x2 := fiat.cmovznz_u64(fiat.u1(arg2), out1[1], arg1[1])
x3 := fiat.cmovznz_u64(fiat.u1(arg2), out1[2], arg1[2])
@@ -596,7 +597,8 @@ fe_set :: proc "contextless" (out1, arg1: ^Tight_Field_Element) {
out1[4] = x5
}
-fe_cond_swap :: proc "contextless" (out1, out2: ^Tight_Field_Element, arg1: int) {
+@(optimization_mode="none")
+fe_cond_swap :: #force_no_inline proc "contextless" (out1, out2: ^Tight_Field_Element, arg1: int) {
mask := -u64(arg1)
x := (out1[0] ~ out2[0]) & mask
x1, y1 := out1[0] ~ x, out2[0] ~ x
diff --git a/core/crypto/_fiat/field_poly1305/field4344.odin b/core/crypto/_fiat/field_poly1305/field4344.odin
index ba9bc2694..8e8a7cc78 100644
--- a/core/crypto/_fiat/field_poly1305/field4344.odin
+++ b/core/crypto/_fiat/field_poly1305/field4344.odin
@@ -201,7 +201,8 @@ fe_opp :: proc "contextless" (out1: ^Loose_Field_Element, arg1: ^Tight_Field_Ele
out1[2] = x3
}
-fe_cond_assign :: proc "contextless" (out1, arg1: ^Tight_Field_Element, arg2: bool) {
+@(optimization_mode="none")
+fe_cond_assign :: #force_no_inline proc "contextless" (out1, arg1: ^Tight_Field_Element, arg2: bool) {
x1 := fiat.cmovznz_u64(fiat.u1(arg2), out1[0], arg1[0])
x2 := fiat.cmovznz_u64(fiat.u1(arg2), out1[1], arg1[1])
x3 := fiat.cmovznz_u64(fiat.u1(arg2), out1[2], arg1[2])
@@ -342,7 +343,8 @@ fe_set :: #force_inline proc "contextless" (out1, arg1: ^Tight_Field_Element) {
out1[2] = x3
}
-fe_cond_swap :: proc "contextless" (out1, out2: ^Tight_Field_Element, arg1: bool) {
+@(optimization_mode="none")
+fe_cond_swap :: #force_no_inline proc "contextless" (out1, out2: ^Tight_Field_Element, arg1: bool) {
mask := -u64(arg1)
x := (out1[0] ~ out2[0]) & mask
x1, y1 := out1[0] ~ x, out2[0] ~ x