Module Name: src
Committed By: riastradh
Date: Sun Jul 19 15:33:08 UTC 2020
Modified Files:
src/crypto/external/bsd/openssl/dist/crypto: ppccap.c
Log Message:
Expand on importance of not using fpu for crypto if there's no fpu.
To generate a diff of this commit:
cvs rdiff -u -r1.17 -r1.18 \
src/crypto/external/bsd/openssl/dist/crypto/ppccap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/crypto/external/bsd/openssl/dist/crypto/ppccap.c
diff -u src/crypto/external/bsd/openssl/dist/crypto/ppccap.c:1.17 src/crypto/external/bsd/openssl/dist/crypto/ppccap.c:1.18
--- src/crypto/external/bsd/openssl/dist/crypto/ppccap.c:1.17 Wed Jul 15 08:14:41 2020
+++ src/crypto/external/bsd/openssl/dist/crypto/ppccap.c Sun Jul 19 15:33:08 2020
@@ -374,8 +374,11 @@ void OPENSSL_cpuid_setup(void)
size_t len = sizeof(val);
/*
- * If machdep.fpu_present == 0, FPU is absent and emulated by software.
- * Avoid using it for better performance.
+ * If machdep.fpu_present == 0, FPU is absent and emulated by
+ * software. In that case, using FPU instructions hurts rather
+ * than helps performance, and the software is unlikely to run in
+ * constant time so it would expose us to timing side channel
+ * attacks. So don't do it!
*/
error = sysctlbyname("machdep.fpu_present", &val, &len, NULL, 0);
if (error != 0 || (error == 0 && val != 0))
