From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter =?utf-8?q?M=C3=BCller?= To: development@lists.ipfire.org Subject: [PATCH] linux: Do not allow slab caches to be merged Date: Mon, 01 Aug 2022 17:39:59 +0000 Message-ID: <8bb7718c-1f3b-1882-c081-4b3d31dcda9f@ipfire.org> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0638101046113519184==" List-Id: --===============0638101046113519184== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable >>From the kernel documentation: > For reduced kernel memory fragmentation, slab caches can be > merged when they share the same size and other characteristics. > This carries a risk of kernel heap overflows being able to > overwrite objects from merged caches (and more easily control > cache layout), which makes such heap attacks easier to exploit > by attackers. By keeping caches unmerged, these kinds of exploits > can usually only damage objects in the same cache. [...] Thus, it is more sane to leave slab merging disabled. KSPP and ClipOS recommend this as well. Signed-off-by: Peter M=C3=BCller --- config/kernel/kernel.config.aarch64-ipfire | 2 +- config/kernel/kernel.config.armv6l-ipfire | 2 +- config/kernel/kernel.config.riscv64-ipfire | 2 +- config/kernel/kernel.config.x86_64-ipfire | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/config/kernel/kernel.config.aarch64-ipfire b/config/kernel/kerne= l.config.aarch64-ipfire index 9232335ff..023c3d5aa 100644 --- a/config/kernel/kernel.config.aarch64-ipfire +++ b/config/kernel/kernel.config.aarch64-ipfire @@ -247,7 +247,7 @@ CONFIG_VM_EVENT_COUNTERS=3Dy # CONFIG_SLAB is not set CONFIG_SLUB=3Dy # CONFIG_SLOB is not set -CONFIG_SLAB_MERGE_DEFAULT=3Dy +# CONFIG_SLAB_MERGE_DEFAULT is not set CONFIG_SLAB_FREELIST_RANDOM=3Dy CONFIG_SLAB_FREELIST_HARDENED=3Dy CONFIG_SHUFFLE_PAGE_ALLOCATOR=3Dy diff --git a/config/kernel/kernel.config.armv6l-ipfire b/config/kernel/kernel= .config.armv6l-ipfire index dc0aee51b..b4587826e 100644 --- a/config/kernel/kernel.config.armv6l-ipfire +++ b/config/kernel/kernel.config.armv6l-ipfire @@ -250,7 +250,7 @@ CONFIG_VM_EVENT_COUNTERS=3Dy # CONFIG_SLAB is not set CONFIG_SLUB=3Dy # CONFIG_SLOB is not set -CONFIG_SLAB_MERGE_DEFAULT=3Dy +# CONFIG_SLAB_MERGE_DEFAULT is not set CONFIG_SLAB_FREELIST_RANDOM=3Dy CONFIG_SLAB_FREELIST_HARDENED=3Dy CONFIG_SHUFFLE_PAGE_ALLOCATOR=3Dy diff --git a/config/kernel/kernel.config.riscv64-ipfire b/config/kernel/kerne= l.config.riscv64-ipfire index 0801f4389..fb7cda4dd 100644 --- a/config/kernel/kernel.config.riscv64-ipfire +++ b/config/kernel/kernel.config.riscv64-ipfire @@ -230,7 +230,7 @@ CONFIG_VM_EVENT_COUNTERS=3Dy # CONFIG_SLAB is not set CONFIG_SLUB=3Dy # CONFIG_SLOB is not set -CONFIG_SLAB_MERGE_DEFAULT=3Dy +# CONFIG_SLAB_MERGE_DEFAULT is not set CONFIG_SLAB_FREELIST_RANDOM=3Dy CONFIG_SLAB_FREELIST_HARDENED=3Dy CONFIG_SHUFFLE_PAGE_ALLOCATOR=3Dy diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel= .config.x86_64-ipfire index 40975b5fc..d3792cbb7 100644 --- a/config/kernel/kernel.config.x86_64-ipfire +++ b/config/kernel/kernel.config.x86_64-ipfire @@ -270,7 +270,7 @@ CONFIG_VM_EVENT_COUNTERS=3Dy # CONFIG_SLAB is not set CONFIG_SLUB=3Dy # CONFIG_SLOB is not set -CONFIG_SLAB_MERGE_DEFAULT=3Dy +# CONFIG_SLAB_MERGE_DEFAULT is not set CONFIG_SLAB_FREELIST_RANDOM=3Dy CONFIG_SLAB_FREELIST_HARDENED=3Dy CONFIG_SHUFFLE_PAGE_ALLOCATOR=3Dy --=20 2.35.3 --===============0638101046113519184==--