linux/security/Kconfig

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#
# Security configuration
#
menu "Security options"
source security/keys/Kconfig
config SECURITY_DMESG_RESTRICT
bool "Restrict unprivileged access to the kernel syslog"
default n
help
This enforces restrictions on unprivileged users reading the kernel
syslog via dmesg(8).
If this option is not selected, no restrictions will be enforced
unless the dmesg_restrict sysctl is explicitly set to (1).
If you are unsure how to answer this question, answer N.
config SECURITY
bool "Enable different security models"
depends on SYSFS
kernel: conditionally support non-root users, groups and capabilities There are a lot of embedded systems that run most or all of their functionality in init, running as root:root. For these systems, supporting multiple users is not necessary. This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for non-root users, non-root groups, and capabilities optional. It is enabled under CONFIG_EXPERT menu. When this symbol is not defined, UID and GID are zero in any possible case and processes always have all capabilities. The following syscalls are compiled out: setuid, setregid, setgid, setreuid, setresuid, getresuid, setresgid, getresgid, setgroups, getgroups, setfsuid, setfsgid, capget, capset. Also, groups.c is compiled out completely. In kernel/capability.c, capable function was moved in order to avoid adding two ifdef blocks. This change saves about 25 KB on a defconfig build. The most minimal kernels have total text sizes in the high hundreds of kB rather than low MB. (The 25k goes down a bit with allnoconfig, but not that much. The kernel was booted in Qemu. All the common functionalities work. Adding users/groups is not possible, failing with -ENOSYS. Bloat-o-meter output: add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-16 01:16:41 +02:00
depends on MULTIUSER
help
This allows you to choose different security modules to be
configured into your kernel.
If this option is not selected, the default Linux security
model will be used.
If you are unsure how to answer this question, answer N.
config SECURITY_WRITABLE_HOOKS
depends on SECURITY
bool
default n
config SECURITYFS
bool "Enable the securityfs filesystem"
help
This will build the securityfs filesystem. It is currently used by
the TPM bios character driver and IMA, an integrity provider. It is
not used by SELinux or SMACK.
If you are unsure how to answer this question, answer N.
config SECURITY_NETWORK
bool "Socket and Networking Security Hooks"
depends on SECURITY
help
This enables the socket and networking security hooks.
If enabled, a security module can use these hooks to
implement socket and networking access controls.
If you are unsure how to answer this question, answer N.
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 08:12:27 +01:00
IB/core: Enforce PKey security on QPs Add new LSM hooks to allocate and free security contexts and check for permission to access a PKey. Allocate and free a security context when creating and destroying a QP. This context is used for controlling access to PKeys. When a request is made to modify a QP that changes the port, PKey index, or alternate path, check that the QP has permission for the PKey in the PKey table index on the subnet prefix of the port. If the QP is shared make sure all handles to the QP also have access. Store which port and PKey index a QP is using. After the reset to init transition the user can modify the port, PKey index and alternate path independently. So port and PKey settings changes can be a merge of the previous settings and the new ones. In order to maintain access control if there are PKey table or subnet prefix change keep a list of all QPs are using each PKey index on each port. If a change occurs all QPs using that device and port must have access enforced for the new cache settings. These changes add a transaction to the QP modify process. Association with the old port and PKey index must be maintained if the modify fails, and must be removed if it succeeds. Association with the new port and PKey index must be established prior to the modify and removed if the modify fails. 1. When a QP is modified to a particular Port, PKey index or alternate path insert that QP into the appropriate lists. 2. Check permission to access the new settings. 3. If step 2 grants access attempt to modify the QP. 4a. If steps 2 and 3 succeed remove any prior associations. 4b. If ether fails remove the new setting associations. If a PKey table or subnet prefix changes walk the list of QPs and check that they have permission. If not send the QP to the error state and raise a fatal error event. If it's a shared QP make sure all the QPs that share the real_qp have permission as well. If the QP that owns a security structure is denied access the security structure is marked as such and the QP is added to an error_list. Once the moving the QP to error is complete the security structure mark is cleared. Maintaining the lists correctly turns QP destroy into a transaction. The hardware driver for the device frees the ib_qp structure, so while the destroy is in progress the ib_qp pointer in the ib_qp_security struct is undefined. When the destroy process begins the ib_qp_security structure is marked as destroying. This prevents any action from being taken on the QP pointer. After the QP is destroyed successfully it could still listed on an error_list wait for it to be processed by that flow before cleaning up the structure. If the destroy fails the QPs port and PKey settings are reinserted into the appropriate lists, the destroying flag is cleared, and access control is enforced, in case there were any cache changes during the destroy flow. To keep the security changes isolated a new file is used to hold security related functionality. Signed-off-by: Daniel Jurgens <danielj@mellanox.com> Acked-by: Doug Ledford <dledford@redhat.com> [PM: merge fixup in ib_verbs.h and uverbs_cmd.c] Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-19 14:48:52 +02:00
config SECURITY_INFINIBAND
bool "Infiniband Security Hooks"
depends on SECURITY && INFINIBAND
help
This enables the Infiniband security hooks.
If enabled, a security module can use these hooks to
implement Infiniband access controls.
If you are unsure how to answer this question, answer N.
[LSM-IPSec]: Security association restriction. This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 08:12:27 +01:00
config SECURITY_NETWORK_XFRM
bool "XFRM (IPSec) Networking Security Hooks"
depends on XFRM && SECURITY_NETWORK
help
This enables the XFRM (IPSec) networking security hooks.
If enabled, a security module can use these hooks to
implement per-packet access controls based on labels
derived from IPSec policy. Non-IPSec communications are
designated as unlabelled, and only sockets authorized
to communicate unlabelled data can send without using
IPSec.
If you are unsure how to answer this question, answer N.
config SECURITY_PATH
bool "Security hooks for pathname based access control"
depends on SECURITY
help
This enables the security hooks for pathname based access control.
If enabled, a security module can use these hooks to
implement pathname based access controls.
If you are unsure how to answer this question, answer N.
x86, intel_txt: Intel TXT boot support This patch adds kernel configuration and boot support for Intel Trusted Execution Technology (Intel TXT). Intel's technology for safer computing, Intel Trusted Execution Technology (Intel TXT), defines platform-level enhancements that provide the building blocks for creating trusted platforms. Intel TXT was formerly known by the code name LaGrande Technology (LT). Intel TXT in Brief: o Provides dynamic root of trust for measurement (DRTM) o Data protection in case of improper shutdown o Measurement and verification of launched environment Intel TXT is part of the vPro(TM) brand and is also available some non-vPro systems. It is currently available on desktop systems based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45 Express chipsets. For more information, see http://www.intel.com/technology/security/. This site also has a link to the Intel TXT MLE Developers Manual, which has been updated for the new released platforms. A much more complete description of how these patches support TXT, how to configure a system for it, etc. is in the Documentation/intel_txt.txt file in this patch. This patch provides the TXT support routines for complete functionality, documentation for TXT support and for the changes to the boot_params structure, and boot detection of a TXT launch. Attempts to shutdown (reboot, Sx) the system will result in platform resets; subsequent patches will support these shutdown modes properly. Documentation/intel_txt.txt | 210 +++++++++++++++++++++ Documentation/x86/zero-page.txt | 1 arch/x86/include/asm/bootparam.h | 3 arch/x86/include/asm/fixmap.h | 3 arch/x86/include/asm/tboot.h | 197 ++++++++++++++++++++ arch/x86/kernel/Makefile | 1 arch/x86/kernel/setup.c | 4 arch/x86/kernel/tboot.c | 379 +++++++++++++++++++++++++++++++++++++++ security/Kconfig | 30 +++ 9 files changed, 827 insertions(+), 1 deletion(-) Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> Signed-off-by: Shane Wang <shane.wang@intel.com> Signed-off-by: Gang Wei <gang.wei@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-01 04:30:59 +02:00
config INTEL_TXT
bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
depends on HAVE_INTEL_TXT
x86, intel_txt: Intel TXT boot support This patch adds kernel configuration and boot support for Intel Trusted Execution Technology (Intel TXT). Intel's technology for safer computing, Intel Trusted Execution Technology (Intel TXT), defines platform-level enhancements that provide the building blocks for creating trusted platforms. Intel TXT was formerly known by the code name LaGrande Technology (LT). Intel TXT in Brief: o Provides dynamic root of trust for measurement (DRTM) o Data protection in case of improper shutdown o Measurement and verification of launched environment Intel TXT is part of the vPro(TM) brand and is also available some non-vPro systems. It is currently available on desktop systems based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45 Express chipsets. For more information, see http://www.intel.com/technology/security/. This site also has a link to the Intel TXT MLE Developers Manual, which has been updated for the new released platforms. A much more complete description of how these patches support TXT, how to configure a system for it, etc. is in the Documentation/intel_txt.txt file in this patch. This patch provides the TXT support routines for complete functionality, documentation for TXT support and for the changes to the boot_params structure, and boot detection of a TXT launch. Attempts to shutdown (reboot, Sx) the system will result in platform resets; subsequent patches will support these shutdown modes properly. Documentation/intel_txt.txt | 210 +++++++++++++++++++++ Documentation/x86/zero-page.txt | 1 arch/x86/include/asm/bootparam.h | 3 arch/x86/include/asm/fixmap.h | 3 arch/x86/include/asm/tboot.h | 197 ++++++++++++++++++++ arch/x86/kernel/Makefile | 1 arch/x86/kernel/setup.c | 4 arch/x86/kernel/tboot.c | 379 +++++++++++++++++++++++++++++++++++++++ security/Kconfig | 30 +++ 9 files changed, 827 insertions(+), 1 deletion(-) Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> Signed-off-by: Shane Wang <shane.wang@intel.com> Signed-off-by: Gang Wei <gang.wei@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-01 04:30:59 +02:00
help
This option enables support for booting the kernel with the
Trusted Boot (tboot) module. This will utilize
Intel(R) Trusted Execution Technology to perform a measured launch
of the kernel. If the system does not support Intel(R) TXT, this
will have no effect.
Intel TXT will provide higher assurance of system configuration and
x86, intel_txt: Intel TXT boot support This patch adds kernel configuration and boot support for Intel Trusted Execution Technology (Intel TXT). Intel's technology for safer computing, Intel Trusted Execution Technology (Intel TXT), defines platform-level enhancements that provide the building blocks for creating trusted platforms. Intel TXT was formerly known by the code name LaGrande Technology (LT). Intel TXT in Brief: o Provides dynamic root of trust for measurement (DRTM) o Data protection in case of improper shutdown o Measurement and verification of launched environment Intel TXT is part of the vPro(TM) brand and is also available some non-vPro systems. It is currently available on desktop systems based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45 Express chipsets. For more information, see http://www.intel.com/technology/security/. This site also has a link to the Intel TXT MLE Developers Manual, which has been updated for the new released platforms. A much more complete description of how these patches support TXT, how to configure a system for it, etc. is in the Documentation/intel_txt.txt file in this patch. This patch provides the TXT support routines for complete functionality, documentation for TXT support and for the changes to the boot_params structure, and boot detection of a TXT launch. Attempts to shutdown (reboot, Sx) the system will result in platform resets; subsequent patches will support these shutdown modes properly. Documentation/intel_txt.txt | 210 +++++++++++++++++++++ Documentation/x86/zero-page.txt | 1 arch/x86/include/asm/bootparam.h | 3 arch/x86/include/asm/fixmap.h | 3 arch/x86/include/asm/tboot.h | 197 ++++++++++++++++++++ arch/x86/kernel/Makefile | 1 arch/x86/kernel/setup.c | 4 arch/x86/kernel/tboot.c | 379 +++++++++++++++++++++++++++++++++++++++ security/Kconfig | 30 +++ 9 files changed, 827 insertions(+), 1 deletion(-) Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> Signed-off-by: Shane Wang <shane.wang@intel.com> Signed-off-by: Gang Wei <gang.wei@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-01 04:30:59 +02:00
initial state as well as data reset protection. This is used to
create a robust initial kernel measurement and verification, which
helps to ensure that kernel security mechanisms are functioning
correctly. This level of protection requires a root of trust outside
of the kernel itself.
Intel TXT also helps solve real end user concerns about having
confidence that their hardware is running the VMM or kernel that
it was configured with, especially since they may be responsible for
x86, intel_txt: Intel TXT boot support This patch adds kernel configuration and boot support for Intel Trusted Execution Technology (Intel TXT). Intel's technology for safer computing, Intel Trusted Execution Technology (Intel TXT), defines platform-level enhancements that provide the building blocks for creating trusted platforms. Intel TXT was formerly known by the code name LaGrande Technology (LT). Intel TXT in Brief: o Provides dynamic root of trust for measurement (DRTM) o Data protection in case of improper shutdown o Measurement and verification of launched environment Intel TXT is part of the vPro(TM) brand and is also available some non-vPro systems. It is currently available on desktop systems based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45 Express chipsets. For more information, see http://www.intel.com/technology/security/. This site also has a link to the Intel TXT MLE Developers Manual, which has been updated for the new released platforms. A much more complete description of how these patches support TXT, how to configure a system for it, etc. is in the Documentation/intel_txt.txt file in this patch. This patch provides the TXT support routines for complete functionality, documentation for TXT support and for the changes to the boot_params structure, and boot detection of a TXT launch. Attempts to shutdown (reboot, Sx) the system will result in platform resets; subsequent patches will support these shutdown modes properly. Documentation/intel_txt.txt | 210 +++++++++++++++++++++ Documentation/x86/zero-page.txt | 1 arch/x86/include/asm/bootparam.h | 3 arch/x86/include/asm/fixmap.h | 3 arch/x86/include/asm/tboot.h | 197 ++++++++++++++++++++ arch/x86/kernel/Makefile | 1 arch/x86/kernel/setup.c | 4 arch/x86/kernel/tboot.c | 379 +++++++++++++++++++++++++++++++++++++++ security/Kconfig | 30 +++ 9 files changed, 827 insertions(+), 1 deletion(-) Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> Signed-off-by: Shane Wang <shane.wang@intel.com> Signed-off-by: Gang Wei <gang.wei@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-01 04:30:59 +02:00
providing such assurances to VMs and services running on it.
See <http://www.intel.com/technology/security/> for more information
about Intel(R) TXT.
See <http://tboot.sourceforge.net> for more information about tboot.
See Documentation/intel_txt.txt for a description of how to enable
Intel TXT support in a kernel boot.
If you are unsure as to whether this is required, answer N.
config LSM_MMAP_MIN_ADDR
int "Low address space for LSM to protect from user allocation"
depends on SECURITY && SECURITY_SELINUX
default 32768 if ARM || (ARM64 && COMPAT)
default 65536
help
This is the portion of low virtual memory which should be protected
from userspace allocation. Keeping a user from writing to low pages
can help reduce the impact of kernel NULL pointer bugs.
For most ia64, ppc64 and x86 users with lots of address space
a value of 65536 is reasonable and should cause no problems.
On arm and other archs it should not be higher than 32768.
Programs which use vm86 functionality or have some need to map
this low address space will need the permission specific to the
systems running LSM.
config HAVE_HARDENED_USERCOPY_ALLOCATOR
bool
help
The heap allocator implements __check_heap_object() for
validating memory ranges against heap object sizes in
support of CONFIG_HARDENED_USERCOPY.
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
select BUG
help
This option checks for obviously wrong memory regions when
copying memory to/from the kernel (via copy_to_user() and
copy_from_user() functions) by rejecting memory ranges that
are larger than the specified heap object, span multiple
separately allocated pages, are not on the process stack,
or are part of the kernel text. This kills entire classes
of heap overflow exploits and similar kernel memory exposures.
config HARDENED_USERCOPY_PAGESPAN
bool "Refuse to copy allocations that span multiple pages"
depends on HARDENED_USERCOPY
- force check_object_size() to be inline too - move page-spanning check behind a CONFIG since it's triggering false positives -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Kees Cook <kees@outflux.net> iQIcBAABCgAGBQJX0F3qAAoJEIly9N/cbcAmaxEP/R737i+XhP4VOv+rYW050NHB K+FDeLv5/Gx56JrHRRWwj80K5/9F09wS929AWcaTDjEb2NKp/o/6W/gN1eVdGlJF K3UQk+Kmncb44poVoHkjMRAl6+sfKm6mTWZBTjBECKwQuCFyDoDoqDXhn5IXTlw9 Ig+TTOSgNw9gRke3ECtFynbVnDWx/Ry/axfT9vGXhFOkWclMUFy2UOdDSTtFAB6x yw5hdrfGakk2BPscHLO1xNqRuVLRUSXZVUiJGIQ6AiUupm34Yqmm69mrMuxaOtPC Ai3zhNGDuYClcGJAiPJYX+7nRjgPCWAdlyzQqLp5hwx63TJ+gxvhmxoFOJxEmHE/ 99i2Ak073Es6WII532Eknk3vV+UJzQNT/HO+0LcrJFkOEp9EHfVUb19CngQTaX7Q UbfYdyFgp3y24cRp7v0tP8gE2LCrsRe0UEhUq2NGmrerw3caNqZGHS9Od5OYEM8D uIhaotWoOv9Z0r+DZMGkUjfqeLb6RWNcUoWc5wZ3VYG27BM/pfhRxKf/2aw6O9u0 2Jk1QJxBr+/8DQ500xu/IBOP9V7aGAc4nxKyqUlwA05/JEFGiAzCwqfZW5CKTxgD 5Ht994WbTEH3/VaAskKnwggeHvttiEpehBCdVA4bXuhBhJhmPjFiKHX7uRrcM2GV /yH3UTkPnr/VD/I2ndiX =r8BE -----END PGP SIGNATURE----- Merge tag 'usercopy-v4.8-rc6-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull more hardened usercopyfixes from Kees Cook: - force check_object_size() to be inline too - move page-spanning check behind a CONFIG since it's triggering false positives [ Changed the page-spanning config option to depend on EXPERT in the merge. That way it still gets build testing, and you can enable it if you want to, but is never enabled for "normal" configurations ] * tag 'usercopy-v4.8-rc6-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: usercopy: remove page-spanning test for now usercopy: force check_object_size() inline
2016-09-07 23:03:49 +02:00
depends on EXPERT
help
When a multi-page allocation is done without __GFP_COMP,
hardened usercopy will reject attempts to copy it. There are,
however, several cases of this in the kernel that have not all
been removed. This config is intended to be used only while
trying to find such users.
include/linux/string.h: add the option of fortified string.h functions This adds support for compiling with a rough equivalent to the glibc _FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer overflow checks for string.h functions when the compiler determines the size of the source or destination buffer at compile-time. Unlike glibc, it covers buffer reads in addition to writes. GNU C __builtin_*_chk intrinsics are avoided because they would force a much more complex implementation. They aren't designed to detect read overflows and offer no real benefit when using an implementation based on inline checks. Inline checks don't add up to much code size and allow full use of the regular string intrinsics while avoiding the need for a bunch of _chk functions and per-arch assembly to avoid wrapper overhead. This detects various overflows at compile-time in various drivers and some non-x86 core kernel code. There will likely be issues caught in regular use at runtime too. Future improvements left out of initial implementation for simplicity, as it's all quite optional and can be done incrementally: * Some of the fortified string functions (strncpy, strcat), don't yet place a limit on reads from the source based on __builtin_object_size of the source buffer. * Extending coverage to more string functions like strlcat. * It should be possible to optionally use __builtin_object_size(x, 1) for some functions (C strings) to detect intra-object overflows (like glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative approach to avoid likely compatibility issues. * The compile-time checks should be made available via a separate config option which can be enabled by default (or always enabled) once enough time has passed to get the issues it catches fixed. Kees said: "This is great to have. While it was out-of-tree code, it would have blocked at least CVE-2016-3858 from being exploitable (improper size argument to strlcpy()). I've sent a number of fixes for out-of-bounds-reads that this detected upstream already" [arnd@arndb.de: x86: fix fortified memcpy] Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de [keescook@chromium.org: avoid panic() in favor of BUG()] Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast [keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help] Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org Signed-off-by: Daniel Micay <danielmicay@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Daniel Axtens <dja@axtens.net> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 23:36:10 +02:00
config FORTIFY_SOURCE
bool "Harden common str/mem functions against buffer overflows"
depends on ARCH_HAS_FORTIFY_SOURCE
help
Detect overflows of buffers in common string and memory functions
where the compiler can determine and validate the buffer sizes.
config STATIC_USERMODEHELPER
bool "Force all usermode helper calls through a single binary"
help
By default, the kernel can call many different userspace
binary programs through the "usermode helper" kernel
interface. Some of these binaries are statically defined
either in the kernel code itself, or as a kernel configuration
option. However, some of these are dynamically created at
runtime, or can be modified after the kernel has started up.
To provide an additional layer of security, route all of these
calls through a single executable that can not have its name
changed.
Note, it is up to this single binary to then call the relevant
"real" usermode helper binary, based on the first argument
passed to it. If desired, this program can filter and pick
and choose what real programs are called.
If you wish for all usermode helper programs are to be
disabled, choose this option and then set
STATIC_USERMODEHELPER_PATH to an empty string.
config STATIC_USERMODEHELPER_PATH
string "Path to the static usermode helper binary"
depends on STATIC_USERMODEHELPER
default "/sbin/usermode-helper"
help
The binary called by the kernel when any usermode helper
program is wish to be run. The "real" application's name will
be in the first argument passed to this program on the command
line.
If you wish for all usermode helper programs to be disabled,
specify an empty string here (i.e. "").
source security/selinux/Kconfig
Smack: Simplified Mandatory Access Control Kernel Smack is the Simplified Mandatory Access Control Kernel. Smack implements mandatory access control (MAC) using labels attached to tasks and data containers, including files, SVIPC, and other tasks. Smack is a kernel based scheme that requires an absolute minimum of application support and a very small amount of configuration data. Smack uses extended attributes and provides a set of general mount options, borrowing technics used elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides a pseudo-filesystem smackfs that is used for manipulation of system Smack attributes. The patch, patches for ls and sshd, a README, a startup script, and x86 binaries for ls and sshd are also available on http://www.schaufler-ca.com Development has been done using Fedora Core 7 in a virtual machine environment and on an old Sony laptop. Smack provides mandatory access controls based on the label attached to a task and the label attached to the object it is attempting to access. Smack labels are deliberately short (1-23 characters) text strings. Single character labels using special characters are reserved for system use. The only operation applied to Smack labels is equality comparison. No wildcards or expressions, regular or otherwise, are used. Smack labels are composed of printable characters and may not include "/". A file always gets the Smack label of the task that created it. Smack defines and uses these labels: "*" - pronounced "star" "_" - pronounced "floor" "^" - pronounced "hat" "?" - pronounced "huh" The access rules enforced by Smack are, in order: 1. Any access requested by a task labeled "*" is denied. 2. A read or execute access requested by a task labeled "^" is permitted. 3. A read or execute access requested on an object labeled "_" is permitted. 4. Any access requested on an object labeled "*" is permitted. 5. Any access requested by a task on an object with the same label is permitted. 6. Any access requested that is explicitly defined in the loaded rule set is permitted. 7. Any other access is denied. Rules may be explicitly defined by writing subject,object,access triples to /smack/load. Smack rule sets can be easily defined that describe Bell&LaPadula sensitivity, Biba integrity, and a variety of interesting configurations. Smack rule sets can be modified on the fly to accommodate changes in the operating environment or even the time of day. Some practical use cases: Hierarchical levels. The less common of the two usual uses for MLS systems is to define hierarchical levels, often unclassified, confidential, secret, and so on. To set up smack to support this, these rules could be defined: C Unclass rx S C rx S Unclass rx TS S rx TS C rx TS Unclass rx A TS process can read S, C, and Unclass data, but cannot write it. An S process can read C and Unclass. Note that specifying that TS can read S and S can read C does not imply TS can read C, it has to be explicitly stated. Non-hierarchical categories. This is the more common of the usual uses for an MLS system. Since the default rule is that a subject cannot access an object with a different label no access rules are required to implement compartmentalization. A case that the Bell & LaPadula policy does not allow is demonstrated with this Smack access rule: A case that Bell&LaPadula does not allow that Smack does: ESPN ABC r ABC ESPN r On my portable video device I have two applications, one that shows ABC programming and the other ESPN programming. ESPN wants to show me sport stories that show up as news, and ABC will only provide minimal information about a sports story if ESPN is covering it. Each side can look at the other's info, neither can change the other. Neither can see what FOX is up to, which is just as well all things considered. Another case that I especially like: SatData Guard w Guard Publish w A program running with the Guard label opens a UDP socket and accepts messages sent by a program running with a SatData label. The Guard program inspects the message to ensure it is wholesome and if it is sends it to a program running with the Publish label. This program then puts the information passed in an appropriate place. Note that the Guard program cannot write to a Publish file system object because file system semanitic require read as well as write. The four cases (categories, levels, mutual read, guardbox) here are all quite real, and problems I've been asked to solve over the years. The first two are easy to do with traditonal MLS systems while the last two you can't without invoking privilege, at least for a while. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Cc: Joshua Brindle <method@manicmethod.com> Cc: Paul Moore <paul.moore@hp.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: "Ahmed S. Darwish" <darwish.07@gmail.com> Cc: Andrew G. Morgan <morgan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 07:29:50 +01:00
source security/smack/Kconfig
source security/tomoyo/Kconfig
source security/apparmor/Kconfig
source security/loadpin/Kconfig
source security/yama/Kconfig
source security/integrity/Kconfig
choice
prompt "Default security module"
default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
default DEFAULT_SECURITY_DAC
help
Select the security module that will be used by default if the
kernel parameter security= is not specified.
config DEFAULT_SECURITY_SELINUX
bool "SELinux" if SECURITY_SELINUX=y
config DEFAULT_SECURITY_SMACK
bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
config DEFAULT_SECURITY_TOMOYO
bool "TOMOYO" if SECURITY_TOMOYO=y
config DEFAULT_SECURITY_APPARMOR
bool "AppArmor" if SECURITY_APPARMOR=y
config DEFAULT_SECURITY_DAC
bool "Unix Discretionary Access Controls"
endchoice
config DEFAULT_SECURITY
string
default "selinux" if DEFAULT_SECURITY_SELINUX
default "smack" if DEFAULT_SECURITY_SMACK
default "tomoyo" if DEFAULT_SECURITY_TOMOYO
default "apparmor" if DEFAULT_SECURITY_APPARMOR
default "" if DEFAULT_SECURITY_DAC
endmenu