Date: Tue, 19 Feb 2019 10:23:02 +1100 From: "Tobin C. Harding" <tobin@...nel.org> To: Kees Cook <keescook@...omium.org> Cc: "Tobin C. Harding" <tobin@...nel.org>, Shuah Khan <shuah@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, kernel-hardening@...ts.openwall.com, linux-kernel@...r.kernel.org Subject: [PATCH 0/6] lib: Add safe string funtions No file maintainer, CC'ing all those who touched this file :) And Shua for kselftest stuff. Hi Kess, During your talk at LCA you mentioned that we could do with a couple more safe string functions. One to zero the tail of the destination buffer after call to strscpy() and also the self explanatory strscpy_from_user(). Here is a patch set with my attempts to implement these two functions. While doing this I noticed that we have a test module for lib/string.c (lib/test_string.c) that is not tied into kselftest. So I enable this first up in patch 1. Patch 2 and 3 are function docstring cleanups. Patch 4 adds the copy and zero function, naming it strscpy_zeroed(). I'd love some help naming this better. Patch also adds test code. Patch 5 fixes function docstring to correctly document the behavior of strncpy_from_user(). Patch 6 adds strscpy_from_user(). Does not include test code. I had to do a bit of learning for getting the tests hooked into kselftest, I think its all correct. Module is built correctly when the config option is present and the tests run both via make -C tools/testing/selftests TARGETS=lib run_tests and via loading the module manually. As a side note, this series leaves tools/testing/selftests/lib with 4 shell scripts that are identical except the test name. We could probably do with refactoring them into a single script. Patchset introduces a checkpatch warning WARNING:CONFIG_DESCRIPTION: please write a paragraph that describes the config symbol fully I couldn't work out if this is a false positive or not? Does the new config option CONFIG_TEST_STRING need more documentation? I don't see where extra docs should be added and it seems self explanatory as is. thanks, Tobin. Tobin C. Harding (6): lib/string: Enable string selftesting lib/string: Fix erroneous 'overflow' documentation lib/string: Use correct docstring format lib/string: Add string copy/zero function lib: Fix function documentation for strncpy_from_user lib: Add function strscpy_from_user() include/linux/string.h | 4 ++ lib/Kconfig.debug | 14 +++++++ lib/Makefile | 2 +- lib/string.c | 41 ++++++++++++++---- lib/strncpy_from_user.c | 60 ++++++++++++++++++++++----- lib/test_string.c | 35 +++++++++++++++- tools/testing/selftests/lib/Makefile | 2 +- tools/testing/selftests/lib/config | 1 + tools/testing/selftests/lib/string.sh | 19 +++++++++ 9 files changed, 157 insertions(+), 21 deletions(-) create mode 100755 tools/testing/selftests/lib/string.sh -- 2.20.1
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