Hi Linus, Please pull this fix to my kallsyms_show_value() refactoring for v5.9-rc1. About a month after the original refactoring landed, 0day noticed that there was a path through the kernfs binattr read handlers that did not have PAGE_SIZEd buffers, and the module "sections" read handler made a bad assumption about this, resulting in it stomping on memory when reached through small-sized splice() calls. I've added a set of tests to find these kinds of regressions more quickly in the future as well.
Thanks! -Kees The following changes since commit bcf876870b95592b52519ed4aafcf9d95999bc9c: Linux 5.8 (2020-08-02 14:21:45 -0700) are available in the Git repository at: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git tags/kallsyms_show_value-fix-v5.9-rc1 for you to fetch changes up to 9af47666cb0f331bfcd76799ee368cdfcb00882c: selftests: splice: Check behavior of full and short splices (2020-08-07 10:50:11 -0700) ---------------------------------------------------------------- Fix sysfs module section output overflow ---------------------------------------------------------------- Kees Cook (2): module: Correctly truncate sysfs sections output selftests: splice: Check behavior of full and short splices kernel/module.c | 22 +++++++-- tools/testing/selftests/splice/.gitignore | 1 + tools/testing/selftests/splice/Makefile | 4 +- tools/testing/selftests/splice/config | 1 + tools/testing/selftests/splice/settings | 1 + .../testing/selftests/splice/short_splice_read.sh | 56 +++++++++++++++++++++ tools/testing/selftests/splice/splice_read.c | 57 ++++++++++++++++++++++ 7 files changed, 137 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/splice/config create mode 100644 tools/testing/selftests/splice/settings create mode 100755 tools/testing/selftests/splice/short_splice_read.sh create mode 100644 tools/testing/selftests/splice/splice_read.c -- Kees Cook
