path: root/security/Kconfig
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authorLinus Torvalds <>2018-02-03 16:25:42 -0800
committerLinus Torvalds <>2018-02-03 16:25:42 -0800
commit617aebe6a97efa539cc4b8a52adccd89596e6be0 (patch)
tree51c7753c940fd3727b8cc3e93553c57f89d1d9d2 /security/Kconfig
parent0771ad44a20bc512d1123bac728d3a89ea6febe6 (diff)
parente47e311843dece8073146f3606871280ee9beb87 (diff)
Merge tag 'usercopy-v4.16-rc1' of git://
Pull hardened usercopy whitelisting from Kees Cook: "Currently, hardened usercopy performs dynamic bounds checking on slab cache objects. This is good, but still leaves a lot of kernel memory available to be copied to/from userspace in the face of bugs. To further restrict what memory is available for copying, this creates a way to whitelist specific areas of a given slab cache object for copying to/from userspace, allowing much finer granularity of access control. Slab caches that are never exposed to userspace can declare no whitelist for their objects, thereby keeping them unavailable to userspace via dynamic copy operations. (Note, an implicit form of whitelisting is the use of constant sizes in usercopy operations and get_user()/put_user(); these bypass all hardened usercopy checks since these sizes cannot change at runtime.) This new check is WARN-by-default, so any mistakes can be found over the next several releases without breaking anyone's system. The series has roughly the following sections: - remove %p and improve reporting with offset - prepare infrastructure and whitelist kmalloc - update VFS subsystem with whitelists - update SCSI subsystem with whitelists - update network subsystem with whitelists - update process memory with whitelists - update per-architecture thread_struct with whitelists - update KVM with whitelists and fix ioctl bug - mark all other allocations as not whitelisted - update lkdtm for more sensible test overage" * tag 'usercopy-v4.16-rc1' of git:// (38 commits) lkdtm: Update usercopy tests for whitelisting usercopy: Restrict non-usercopy caches to size 0 kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl kvm: whitelist struct kvm_vcpu_arch arm: Implement thread_struct whitelist for hardened usercopy arm64: Implement thread_struct whitelist for hardened usercopy x86: Implement thread_struct whitelist for hardened usercopy fork: Provide usercopy whitelisting for task_struct fork: Define usercopy region in thread_stack slab caches fork: Define usercopy region in mm_struct slab caches net: Restrict unwhitelisted proto caches to size 0 sctp: Copy struct sctp_sock.autoclose to userspace using put_user() sctp: Define usercopy region in SCTP proto slab cache caif: Define usercopy region in caif proto slab cache ip: Define usercopy region in IP proto slab cache net: Define usercopy region in struct proto slab cache scsi: Define usercopy region in scsi_sense_cache slab cache cifs: Define usercopy region in cifs_request slab cache vxfs: Define usercopy region in vxfs_inode slab cache ufs: Define usercopy region in ufs_inode_cache slab cache ...
Diffstat (limited to 'security/Kconfig')
1 files changed, 14 insertions, 0 deletions
diff --git a/security/Kconfig b/security/Kconfig
index 3709db95027f..c4302067a3ad 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -164,6 +164,20 @@ config HARDENED_USERCOPY
or are part of the kernel text. This kills entire classes
of heap overflow exploits and similar kernel memory exposures.
+ bool "Allow usercopy whitelist violations to fallback to object size"
+ default y
+ help
+ This is a temporary option that allows missing usercopy whitelists
+ to be discovered via a WARN() to the kernel log, instead of
+ rejecting the copy, falling back to non-whitelisted hardened
+ usercopy that checks the slab allocation size instead of the
+ whitelist size. This option will be removed once it seems like
+ all missing usercopy whitelists have been identified and fixed.
+ Booting with "slab_common.usercopy_fallback=Y/N" can change
+ this setting.
bool "Refuse to copy allocations that span multiple pages"