i386 builds fail with GCC7 #385

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opened 2020-03-04 10:40:01 -06:00 by simonbutcher · 2 comments

simonbutcher commented

2020-03-04 10:40:01 -06:00

(Migrated from github.com)

Description

Building with GCC7, the all.sh test test_m32_everest component fails with the following warning:

suites/test_suite_psa_crypto.function: In function 'test_generate_random':
suites/helpers.function:398:25: error: argument 2 value '4294967277' exceeds maximum object size 2147483647 [-Werror=alloc-size-larger-than=]
             ( pointer ) = mbedtls_calloc( sizeof( *( pointer ) ), \
             ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                           ( length ) );           \
                                           ~~~~~~~~~~~~
suites/test_suite_psa_crypto.function:5301:5: note: in expansion of macro 'ASSERT_ALLOC'
In file included from suites/helpers.function:5:0:
/usr/include/stdlib.h:541:14: note: in a call to allocation function 'calloc' declared here
 extern void *calloc (size_t __nmemb, size_t __size)
              ^~~~~~

In the test suite test_suite_psa there's a test case function of generate_random() which takes int as a parameter bytes_arg and assigns it to bytes as a size_t. The parameter comes from the data file so comes in via standard IO so could be at the limit. Within this function, it makes a call to the macro ASSERT_ALLOC(), passing that parameter bytes + sizeof(trail), without any boundary checks on bytes unchecked.

Within ASSERT_ALLOC there is then a call to calloc that takes a parameter of size as size_t, and passes bytes_arg an int into it.

In the Everest m32 test, this is failing with the warning? Why? Well, we've moved from LP64, where int is 32bits, and size_t is 64 bits, to ILP32 where int is 32bits and size_t is 32 bits, leading to a potential underflow.

This issue already has a PR to fix it with PR #377.

Issue request type

[ ] Question
[ ] Enhancement
[x] Bug

### Description Building with GCC7, the `all.sh` test `test_m32_everest` component fails with the following warning: ``` suites/test_suite_psa_crypto.function: In function 'test_generate_random': suites/helpers.function:398:25: error: argument 2 value '4294967277' exceeds maximum object size 2147483647 [-Werror=alloc-size-larger-than=] ( pointer ) = mbedtls_calloc( sizeof( *( pointer ) ), \ ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ( length ) ); \ ~~~~~~~~~~~~ suites/test_suite_psa_crypto.function:5301:5: note: in expansion of macro 'ASSERT_ALLOC' In file included from suites/helpers.function:5:0: /usr/include/stdlib.h:541:14: note: in a call to allocation function 'calloc' declared here extern void *calloc (size_t __nmemb, size_t __size) ^~~~~~ ``` In the test suite `test_suite_psa` there's a test case function of `generate_random()` which takes `int` as a parameter `bytes_arg` and assigns it to `bytes` as a `size_t`. The parameter comes from the data file so comes in via standard IO so could be at the limit. Within this function, it makes a call to the macro `ASSERT_ALLOC()`, passing that parameter `bytes` + `sizeof(trail)`, without any boundary checks on `bytes` unchecked. Within `ASSERT_ALLOC` there is then a call to `calloc` that takes a parameter of size as `size_t`, and passes `bytes_arg` an `int` into it. In the Everest m32 test, this is failing with the warning? Why? Well, we've moved from LP64, where `int` is 32bits, and `size_t` is 64 bits, to ILP32 where `int` is 32bits and `size_t` is 32 bits, leading to a potential underflow. This issue already has a PR to fix it with PR #377. ### Issue request type [ ] Question [ ] Enhancement [x] Bug

gilles-peskine-arm commented

2020-03-04 10:50:35 -06:00

(Migrated from github.com)

More precisely, GCC 7 emits this warning when building with UBSan (-fsanitize=undefined) and -O2. It looks like a GCC bug where some transformations caused by an optimization such as inlining causes additional warnings that are not relevant to the original code. See https://github.com/ARMmbed/mbed-crypto/pull/377#issuecomment-593364500

GCC bug or not, we do want our code to build without warnings on all non-ancient GCC versions.

More precisely, GCC 7 emits this warning when building with UBSan (`-fsanitize=undefined`) and `-O2`. It looks like a GCC bug where some transformations caused by an optimization such as inlining causes additional warnings that are not relevant to the original code. See https://github.com/ARMmbed/mbed-crypto/pull/377#issuecomment-593364500 GCC bug or not, we do want our code to build without warnings on all non-ancient GCC versions.

gilles-peskine-arm commented

2020-09-10 05:40:03 -05:00

(Migrated from github.com)