From 5357164c991e735ef557c04c422709500ee76bc9 Mon Sep 17 00:00:00 2001 From: Simon Butcher Date: Sun, 24 Jun 2018 12:58:31 +0100 Subject: [PATCH 1/3] Add ebx to the i386 clobber list for MPI assembly This fix adds the ebx register to the clobber list for the i386 inline assembly for the multiply helper function. ebx was used but not listed, so when the compiler chose to also use it, ebx was getting corrupted. I'm surprised this wasn't spotted sooner. Fixes Github issues #1550. --- include/mbedtls/bn_mul.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h index f4b2b561d..e04926043 100644 --- a/include/mbedtls/bn_mul.h +++ b/include/mbedtls/bn_mul.h @@ -142,7 +142,7 @@ "movl %%esi, %3 \n\t" \ : "=m" (t), "=m" (c), "=m" (d), "=m" (s) \ : "m" (t), "m" (s), "m" (d), "m" (c), "m" (b) \ - : "eax", "ecx", "edx", "esi", "edi" \ + : "eax", "ebx", "ecx", "edx", "esi", "edi" \ ); #else @@ -154,7 +154,7 @@ "movl %%esi, %3 \n\t" \ : "=m" (t), "=m" (c), "=m" (d), "=m" (s) \ : "m" (t), "m" (s), "m" (d), "m" (c), "m" (b) \ - : "eax", "ecx", "edx", "esi", "edi" \ + : "eax", "ebx", "ecx", "edx", "esi", "edi" \ ); #endif /* SSE2 */ #endif /* i386 */ From 6c34442c87596fa50fce1ce7872dd2574cb7c6f5 Mon Sep 17 00:00:00 2001 From: Simon Butcher Date: Sun, 24 Jun 2018 16:20:56 +0100 Subject: [PATCH 2/3] Add fix for #1550 and credit to the ChangeLog --- ChangeLog | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/ChangeLog b/ChangeLog index 027a97174..ede5b93ce 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ mbed TLS ChangeLog (Sorted per branch, date) += mbed TLS x.xx.x branch released xxxx-xx-xx + +Bugfix + * Fix the inline assembly for the MPI multiply helper function for i386 and + i386 with SSE2. Found by László Langó. Fixes #1550 + = mbed TLS 2.11.0 branch released 2018-06-18 Features From 4b9a3addb6c9a3d4f6b01d3a71f08b3b2b392dba Mon Sep 17 00:00:00 2001 From: Simon Butcher Date: Tue, 10 Jul 2018 20:18:29 +0100 Subject: [PATCH 3/3] Disable use of the i386 assembly for option -O0 We don't compile in the assembly code if compiler optimisations are disabled as the number of registers used in the assembly code doesn't work with the -O0 option. Also anyone select -O0 probably doesn't want to compile in the assembly code anyway. --- include/mbedtls/bn_mul.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h index e04926043..438aa8cea 100644 --- a/include/mbedtls/bn_mul.h +++ b/include/mbedtls/bn_mul.h @@ -49,7 +49,14 @@ /* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */ #if defined(__GNUC__) && \ ( !defined(__ARMCC_VERSION) || __ARMCC_VERSION >= 6000000 ) -#if defined(__i386__) + +/* + * Disable use of the i386 assembly code below if option -O0, to disable all + * compiler optimisations, is passed, detected with __OPTIMIZE__ + * This is done as the number of registers used in the assembly code doesn't + * work with the -O0 option. + */ +#if defined(__i386__) && !defined(__OPTIMIZE__) #define MULADDC_INIT \ asm( \