This patch-set introduces the possibility of protecting memory that has been allocated dynamically. The memory is managed in pools: when a memory pool is turned into R/O, all the memory that is part of it, will become R/O. A R/O pool can be destroyed, to recover its memory, but it cannot be turned back into R/W mode. This is intentional. This feature is meant for data that doesn't need further modifications after initialization. However the data might need to be released, for example as part of module unloading. To do this, the memory must first be freed, then the pool can be destroyed. An example is provided, in the form of self-testing. Changes since the v10 version: Initially I tried to provide support for hardening the LSM hooks, but the LSM code was too much in a flux to have some chance to be merged. Several drop-in replacement for kmalloc based functions, for example kzalloc. >From this perspective I have also modified genalloc, to make its free functionality follow more closely the kfree, which doesn't need to be told the size of the allocation being released. This was sent out for review twice, but it has not received any feedback, so far. Also genalloc now comes with self-testing. The latest can be found also here: https://www.spinics.net/lists/kernel/msg2696152.html The need to integrate with hardened user copy has driven an optimization in the management of vmap_areas, where each struct page in a vmalloc area has a reference to it, saving the search through the various areas. I was planning - and can still do it - to provide hardening for some IMA data, but in the meanwhile it seems that the XFS developers might be interested in htis functionality: http://www.openwall.com/lists/kernel-hardening/2018/01/24/1 So I'm sending it out as preview. Igor Stoppa (6): genalloc: track beginning of allocations genalloc: selftest struct page: add field for vm_struct Protectable Memory Documentation for Pmalloc Pmalloc: self-test Documentation/core-api/pmalloc.txt | 104 ++++++++ include/linux/genalloc-selftest.h | 30 +++ include/linux/genalloc.h | 6 +- include/linux/mm_types.h | 1 + include/linux/pmalloc.h | 215 ++++++++++++++++ include/linux/vmalloc.h | 1 + init/main.c | 2 + lib/Kconfig | 15 ++ lib/Makefile | 1 + lib/genalloc-selftest.c | 402 +++++++++++++++++++++++++++++ lib/genalloc.c | 444 +++++++++++++++++++++---------- mm/Kconfig | 7 + mm/Makefile | 2 + mm/pmalloc-selftest.c | 65 +++++ mm/pmalloc-selftest.h | 30 +++ mm/pmalloc.c | 516 +++++++++++++++++++++++++++++++++++++ mm/usercopy.c | 25 +- mm/vmalloc.c | 18 +- 18 files changed, 1744 insertions(+), 140 deletions(-) create mode 100644 Documentation/core-api/pmalloc.txt create mode 100644 include/linux/genalloc-selftest.h create mode 100644 include/linux/pmalloc.h create mode 100644 lib/genalloc-selftest.c create mode 100644 mm/pmalloc-selftest.c create mode 100644 mm/pmalloc-selftest.h create mode 100644 mm/pmalloc.c -- 2.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
