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2019-01-11LSM: generalize flag passing to security_capableMicah Morton13-67/+71
This patch provides a general mechanism for passing flags to the security_capable LSM hook. It replaces the specific 'audit' flag that is used to tell security_capable whether it should log an audit message for the given capability check. The reason for generalizing this flag passing is so we can add an additional flag that signifies whether security_capable is being called by a setid syscall (which is needed by the proposed SafeSetID LSM). Signed-off-by: Micah Morton <mortonm@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2019-01-10Merge tag 'blob-stacking-security-next' of ↵James Morris39-793/+1133
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into next-general LSM: Module stacking for SARA and Landlock The combined series of LSM refactoring and addition of blob-sharing for SARA and Landlock. From Casey: v5: Include Kees Cook's rework of the lsm command line interface. v4: Finer granularity in the patches and other cleanups suggested by Kees Cook. Removed dead code created by the removal of SELinux credential blob poisoning. v3: Add ipc blob for SARA and task blob for Landlock. Removing the SELinux cred blob pointer poisoning results selinux_is_enabled() being unused, so it and all it's overhead has been removed. Broke up the cred infrastructure patch. v2: Reduce the patchset to what is required to support the proposed SARA and LandLock security modules The SARA security module is intended to be used in conjunction with other security modules. It requires state to be maintained for the credential, which in turn requires a mechanism for sharing the credential security blob. It also uses the ipc security blob. The module also requires mechanism for user space manipulation of the credential information, hence an additional subdirectory in /proc/.../attr. The LandLock security module provides user configurable policy in the secmark mechanism. It requires data in the credential, file, inode and task security blobs. For this to be used along side the existing "major" security modules mechanism for sharing these blobs are provided. A side effect of providing sharing of the crendential security blob is that the TOMOYO module can be used at the same time as the other "major" modules. The mechanism for configuring which security modules are enabled has to change when stacking in enabled. Any module that uses just the security blobs that are shared can be selected. Additionally, one other "major" module can be selected. The security module stacking issues around networking and IPC are not addressed here as they are beyond what is required for TOMOYO, SARA and LandLock.
2019-01-10Merge tag 'v5.0-rc1' into next-generalJames Morris11060-269127/+507251
Linux 5.0-rc1 Sync to pick up LSM stacking work (which is based on -rc1).
2019-01-09TOMOYO: Update LSM flags to no longer be exclusiveKees Cook1-1/+1
With blob sharing in place, TOMOYO is no longer an exclusive LSM, so it can operate separately now. Mark it as such. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Infrastructure management of the ipc security blobCasey Schaufler6-121/+110
Move management of the kern_ipc_perm->security and msg_msg->security blobs out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Smack: Abstract use of ipc security blobsCasey Schaufler2-5/+20
Don't use the ipc->security pointer directly. Don't use the msg_msg->security pointer directly. Provide helper functions that provides the security blob pointers. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Abstract use of ipc security blobsCasey Schaufler2-9/+22
Don't use the ipc->security pointer directly. Don't use the msg_msg->security pointer directly. Provide helper functions that provides the security blob pointers. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Infrastructure management of the task securityCasey Schaufler4-27/+62
Move management of the task_struct->security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. The only user of this blob is AppArmor. The AppArmor use is abstracted to avoid future conflict. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Infrastructure management of the inode securityCasey Schaufler6-98/+93
Move management of the inode->i_security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Smack: Abstract use of inode security blobCasey Schaufler2-18/+23
Don't use the inode->i_security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Abstract use of inode security blobCasey Schaufler3-15/+21
Don't use the inode->i_security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Infrastructure management of the file securityCasey Schaufler8-51/+72
Move management of the file->f_security blob out of the individual security modules and into the infrastructure. The modules no longer allocate or free the data, instead they tell the infrastructure how much space they require. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Smack: Abstract use of file security blobCasey Schaufler2-4/+13
Don't use the file->f_security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Abstract use of file security blobCasey Schaufler2-9/+14
Don't use the file->f_security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Infrastructure management of the cred security blobCasey Schaufler11-102/+162
Move management of the cred security blob out of the security modules and into the security infrastructre. Instead of allocating and freeing space the security modules tell the infrastructure how much space they require. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09TOMOYO: Abstract use of cred security blobCasey Schaufler4-16/+64
Don't use the cred->security pointer directly. Provide helper functions that provide the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09AppArmor: Abstract use of cred security blobCasey Schaufler4-10/+24
Don't use the cred->security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Remove unused selinux_is_enabledCasey Schaufler7-65/+1
There are no longer users of selinux_is_enabled(). Remove it. As selinux_is_enabled() is the only reason for include/linux/selinux.h remove that as well. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Remove cred security blob poisoningCasey Schaufler2-19/+0
The SELinux specific credential poisioning only makes sense if SELinux is managing the credentials. As the intent of this patch set is to move the blob management out of the modules and into the infrastructure, the SELinux specific code has to go. The poisioning could be introduced into the infrastructure at some later date. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09SELinux: Abstract use of cred security blobCasey Schaufler3-29/+34
Don't use the cred->security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Smack: Abstract use of cred security blobCasey Schaufler4-43/+53
Don't use the cred->security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09procfs: add smack subdir to attrsCasey Schaufler5-21/+96
Back in 2007 I made what turned out to be a rather serious mistake in the implementation of the Smack security module. The SELinux module used an interface in /proc to manipulate the security context on processes. Rather than use a similar interface, I used the same interface. The AppArmor team did likewise. Now /proc/.../attr/current will tell you the security "context" of the process, but it will be different depending on the security module you're using. This patch provides a subdirectory in /proc/.../attr for Smack. Smack user space can use the "current" file in this subdirectory and never have to worry about getting SELinux attributes by mistake. Programs that use the old interface will continue to work (or fail, as the case may be) as before. The proposed S.A.R.A security module is dependent on the mechanism to create its own attr subdirectory. The original implementation is by Kees Cook. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09capability: Initialize as LSM_ORDER_FIRSTKees Cook3-8/+8
This converts capabilities to use the new LSM_ORDER_FIRST position. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LSM: Introduce enum lsm_orderKees Cook2-1/+14
In preparation for distinguishing the "capability" LSM from other LSMs, it must be ordered first. This introduces LSM_ORDER_MUTABLE for the general LSMs and LSM_ORDER_FIRST for capability. In the future LSM_ORDER_LAST for could be added for anything that must run last (e.g. Landlock may use this). Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09Yama: Initialize as ordered LSMKees Cook4-8/+8
This converts Yama from being a direct "minor" LSM into an ordered LSM. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LoadPin: Initialize as ordered LSMKees Cook4-45/+8
This converts LoadPin from being a direct "minor" LSM into an ordered LSM. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LSM: Split LSM preparation from initializationKees Cook1-6/+15
Since we already have to do a pass through the LSMs to figure out if exclusive LSMs should be disabled after the first one is seen as enabled, this splits the logic up a bit more cleanly. Now we do a full "prepare" pass through the LSMs (which also allows for later use by the blob-sharing code), before starting the LSM initialization pass. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Add all exclusive LSMs to ordered initializationCasey Schaufler1-25/+20
This removes CONFIG_DEFAULT_SECURITY in favor of the explicit ordering offered by CONFIG_LSM and adds all the exclusive LSMs to the ordered LSM initialization. The old meaning of CONFIG_DEFAULT_SECURITY is now captured by which exclusive LSM is listed first in the LSM order. All LSMs not added to the ordered list are explicitly disabled. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09selinux: Remove SECURITY_SELINUX_BOOTPARAM_VALUEKees Cook2-19/+1
In preparation for removing CONFIG_DEFAULT_SECURITY, this removes the soon-to-be redundant SECURITY_SELINUX_BOOTPARAM_VALUE. Since explicit ordering via CONFIG_LSM or "lsm=" will define whether an LSM is enabled or not, this CONFIG will become effectively ignored, so remove it. However, in order to stay backward-compatible with "security=selinux", the enable variable defaults to true. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09apparmor: Remove SECURITY_APPARMOR_BOOTPARAM_VALUEKees Cook2-17/+1
In preparation for removing CONFIG_DEFAULT_SECURITY, this removes the soon-to-be redundant SECURITY_APPARMOR_BOOTPARAM_VALUE. Since explicit ordering via CONFIG_LSM or "lsm=" will define whether an LSM is enabled or not, this CONFIG will become effectively ignored, so remove it. However, in order to stay backward-compatible with "security=apparmor", the enable variable defaults to true. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Separate idea of "major" LSM from "exclusive" LSMKees Cook6-4/+17
In order to both support old "security=" Legacy Major LSM selection, and handling real exclusivity, this creates LSM_FLAG_EXCLUSIVE and updates the selection logic to handle them. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LSM: Refactor "security=" in terms of enable/disableKees Cook1-8/+20
For what are marked as the Legacy Major LSMs, make them effectively exclusive when selected on the "security=" boot parameter, to handle the future case of when a previously major LSMs become non-exclusive (e.g. when TOMOYO starts blob-sharing). Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LSM: Prepare for reorganizing "security=" logicKees Cook1-9/+8
This moves the string handling for "security=" boot parameter into a stored pointer instead of a string duplicate. This will allow easier handling of the string when switching logic to use the coming enable/disable infrastructure. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com>
2019-01-09LSM: Tie enabling logic to presence in ordered listKees Cook2-4/+12
Until now, any LSM without an enable storage variable was considered enabled. This inverts the logic and sets defaults to true only if the LSM gets added to the ordered initialization list. (And an exception continues for the major LSMs until they are integrated into the ordered initialization in a later patch.) Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Introduce "lsm=" for boottime LSM selectionKees Cook3-2/+19
Provide a way to explicitly choose LSM initialization order via the new "lsm=" comma-separated list of LSMs. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Introduce CONFIG_LSMKees Cook2-5/+31
This provides a way to declare LSM initialization order via the new CONFIG_LSM. Currently only non-major LSMs are recognized. This will be expanded in future patches. Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-09LSM: Build ordered list of LSMs to initializeKees Cook1-5/+53
This constructs an ordered list of LSMs to initialize, using a hard-coded list of only "integrity": minor LSMs continue to have direct hook calls, and major LSMs continue to initialize separately. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2019-01-09LSM: Lift LSM selection out of individual LSMsKees Cook6-53/+71
As a prerequisite to adjusting LSM selection logic in the future, this moves the selection logic up out of the individual major LSMs, making their init functions only run when actually enabled. This considers all LSMs enabled by default unless they specified an external "enable" variable. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com>
2019-01-09LSM: Plumb visibility into optional "enabled" stateKees Cook3-2/+5
In preparation for lifting the "is this LSM enabled?" logic out of the individual LSMs, pass in any special enabled state tracking (as needed for SELinux, AppArmor, and LoadPin). This should be an "int" to include handling any future cases where "enabled" is exposed via sysctl which has no "bool" type. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com>
2019-01-09LSM: Provide separate ordered initializationKees Cook1-0/+21
This provides a place for ordered LSMs to be initialized, separate from the "major" LSMs. This is mainly a copy/paste from major_lsm_init() to ordered_lsm_init(), but it will change drastically in later patches. What is not obvious in the patch is that this change moves the integrity LSM from major_lsm_init() into ordered_lsm_init(), since it is not marked with the LSM_FLAG_LEGACY_MAJOR. As it is the only LSM in the "ordered" list, there is no reordering yet created. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com>
2019-01-09LSM: Introduce LSM_FLAG_LEGACY_MAJORKees Cook5-0/+7
This adds a flag for the current "major" LSMs to distinguish them when we have a universal method for ordering all LSMs. It's called "legacy" since the distinction of "major" will go away in the blob-sharing world. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com>
2019-01-07Linux 5.0-rc1Linus Torvalds1-3/+3
2019-01-07Merge tag 'kbuild-v4.21-3' of ↵Linus Torvalds94-694/+150
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - improve boolinit.cocci and use_after_iter.cocci semantic patches - fix alignment for kallsyms - move 'asm goto' compiler test to Kconfig and clean up jump_label CONFIG option - generate asm-generic wrappers automatically if arch does not implement mandatory UAPI headers - remove redundant generic-y defines - misc cleanups * tag 'kbuild-v4.21-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kconfig: rename generated .*conf-cfg to *conf-cfg kbuild: remove unnecessary stubs for archheader and archscripts kbuild: use assignment instead of define ... endef for filechk_* rules arch: remove redundant UAPI generic-y defines kbuild: generate asm-generic wrappers if mandatory headers are missing arch: remove stale comments "UAPI Header export list" riscv: remove redundant kernel-space generic-y kbuild: change filechk to surround the given command with { } kbuild: remove redundant target cleaning on failure kbuild: clean up rule_dtc_dt_yaml kbuild: remove UIMAGE_IN and UIMAGE_OUT jump_label: move 'asm goto' support test to Kconfig kallsyms: lower alignment on ARM scripts: coccinelle: boolinit: drop warnings on named constants scripts: coccinelle: check for redeclaration kconfig: remove unused "file" field of yylval union nds32: remove redundant kernel-space generic-y nios2: remove unneeded HAS_DMA define
2019-01-07Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds27-166/+620
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf tooling updates form Ingo Molnar: "A final batch of perf tooling changes: mostly fixes and small improvements" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits) perf session: Add comment for perf_session__register_idle_thread() perf thread-stack: Fix thread stack processing for the idle task perf thread-stack: Allocate an array of thread stacks perf thread-stack: Factor out thread_stack__init() perf thread-stack: Allow for a thread stack array perf thread-stack: Avoid direct reference to the thread's stack perf thread-stack: Tidy thread_stack__bottom() usage perf thread-stack: Simplify some code in thread_stack__process() tools gpio: Allow overriding CFLAGS tools power turbostat: Override CFLAGS assignments and add LDFLAGS to build command tools thermal tmon: Allow overriding CFLAGS assignments tools power x86_energy_perf_policy: Override CFLAGS assignments and add LDFLAGS to build command perf c2c: Increase the HITM ratio limit for displayed cachelines perf c2c: Change the default coalesce setup perf trace beauty ioctl: Beautify USBDEVFS_ commands perf trace beauty: Export function to get the files for a thread perf trace: Wire up ioctl's USBDEBFS_ cmd table generator perf beauty ioctl: Add generator for USBDEVFS_ ioctl commands tools headers uapi: Grab a copy of usbdevice_fs.h perf trace: Store the major number for a file when storing its pathname ...
2019-01-07Change mincore() to count "mapped" pages rather than "cached" pagesLinus Torvalds1-81/+13
The semantics of what "in core" means for the mincore() system call are somewhat unclear, but Linux has always (since 2.3.52, which is when mincore() was initially done) treated it as "page is available in page cache" rather than "page is mapped in the mapping". The problem with that traditional semantic is that it exposes a lot of system cache state that it really probably shouldn't, and that users shouldn't really even care about. So let's try to avoid that information leak by simply changing the semantics to be that mincore() counts actual mapped pages, not pages that might be cheaply mapped if they were faulted (note the "might be" part of the old semantics: being in the cache doesn't actually guarantee that you can access them without IO anyway, since things like network filesystems may have to revalidate the cache before use). In many ways the old semantics were somewhat insane even aside from the information leak issue. From the very beginning (and that beginning is a long time ago: 2.3.52 was released in March 2000, I think), the code had a comment saying Later we can get more picky about what "in core" means precisely. and this is that "later". Admittedly it is much later than is really comfortable. NOTE! This is a real semantic change, and it is for example known to change the output of "fincore", since that program literally does a mmmap without populating it, and then doing "mincore()" on that mapping that doesn't actually have any pages in it. I'm hoping that nobody actually has any workflow that cares, and the info leak is real. We may have to do something different if it turns out that people have valid reasons to want the old semantics, and if we can limit the information leak sanely. Cc: Kevin Easton <kevin@guarana.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Masatake YAMATO <yamato@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-07Fix 'acccess_ok()' on alpha and SHLinus Torvalds2-5/+10
Commit 594cc251fdd0 ("make 'user_access_begin()' do 'access_ok()'") broke both alpha and SH booting in qemu, as noticed by Guenter Roeck. It turns out that the bug wasn't actually in that commit itself (which would have been surprising: it was mostly a no-op), but in how the addition of access_ok() to the strncpy_from_user() and strnlen_user() functions now triggered the case where those functions would test the access of the very last byte of the user address space. The string functions actually did that user range test before too, but they did it manually by just comparing against user_addr_max(). But with user_access_begin() doing the check (using "access_ok()"), it now exposed problems in the architecture implementations of that function. For example, on alpha, the access_ok() helper macro looked like this: #define __access_ok(addr, size) \ ((get_fs().seg & (addr | size | (addr+size))) == 0) and what it basically tests is of any of the high bits get set (the USER_DS masking value is 0xfffffc0000000000). And that's completely wrong for the "addr+size" check. Because it's off-by-one for the case where we check to the very end of the user address space, which is exactly what the strn*_user() functions do. Why? Because "addr+size" will be exactly the size of the address space, so trying to access the last byte of the user address space will fail the __access_ok() check, even though it shouldn't. As a result, the user string accessor functions failed consistently - because they literally don't know how long the string is going to be, and the max access is going to be that last byte of the user address space. Side note: that alpha macro is buggy for another reason too - it re-uses the arguments twice. And SH has another version of almost the exact same bug: #define __addr_ok(addr) \ ((unsigned long __force)(addr) < current_thread_info()->addr_limit.seg) so far so good: yes, a user address must be below the limit. But then: #define __access_ok(addr, size) \ (__addr_ok((addr) + (size))) is wrong with the exact same off-by-one case: the case when "addr+size" is exactly _equal_ to the limit is actually perfectly fine (think "one byte access at the last address of the user address space") The SH version is actually seriously buggy in another way: it doesn't actually check for overflow, even though it did copy the _comment_ that talks about overflow. So it turns out that both SH and alpha actually have completely buggy implementations of access_ok(), but they happened to work in practice (although the SH overflow one is a serious serious security bug, not that anybody likely cares about SH security). This fixes the problems by using a similar macro on both alpha and SH. It isn't trying to be clever, the end address is based on this logic: unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b; which basically says "add start and length, and then subtract one unless the length was zero". We can't subtract one for a zero length, or we'd just hit an underflow instead. For a lot of access_ok() users the length is a constant, so this isn't actually as expensive as it initially looks. Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Cc: Matt Turner <mattst88@gmail.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-06Merge tag 'fscrypt_for_linus' of ↵Linus Torvalds7-188/+468
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt Pull fscrypt updates from Ted Ts'o: "Add Adiantum support for fscrypt" * tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt: fscrypt: add Adiantum support
2019-01-06Merge tag 'ext4_for_linus_stable' of ↵Linus Torvalds4-10/+19
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 bug fixes from Ted Ts'o: "Fix a number of ext4 bugs" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix special inode number checks in __ext4_iget() ext4: track writeback errors using the generic tracking infrastructure ext4: use ext4_write_inode() when fsyncing w/o a journal ext4: avoid kernel warning when writing the superblock to a dead device ext4: fix a potential fiemap/page fault deadlock w/ inline_data ext4: make sure enough credits are reserved for dioread_nolock writes
2019-01-06Merge tag 'dma-mapping-4.21-1' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds8-275/+215
Pull dma-mapping fixes from Christoph Hellwig: "Fix various regressions introduced in this cycles: - fix dma-debug tracking for the map_page / map_single consolidatation - properly stub out DMA mapping symbols for !HAS_DMA builds to avoid link failures - fix AMD Gart direct mappings - setup the dma address for no kernel mappings using the remap allocator" * tag 'dma-mapping-4.21-1' of git://git.infradead.org/users/hch/dma-mapping: dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING for remapped allocations x86/amd_gart: fix unmapping of non-GART mappings dma-mapping: remove a few unused exports dma-mapping: properly stub out the DMA API for !CONFIG_HAS_DMA dma-mapping: remove dmam_{declare,release}_coherent_memory dma-mapping: implement dmam_alloc_coherent using dmam_alloc_attrs dma-mapping: implement dma_map_single_attrs using dma_map_page_attrs
2019-01-06Merge tag 'tag-chrome-platform-for-v4.21' of ↵Linus Torvalds3-8/+31
git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform Pull chrome platform updates from Benson Leung: - Changes for EC_MKBP_EVENT_SENSOR_FIFO handling. - Also, maintainership changes. Olofj out, Enric balletbo in. * tag 'tag-chrome-platform-for-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/bleung/chrome-platform: MAINTAINERS: add maintainers for ChromeOS EC sub-drivers MAINTAINERS: platform/chrome: Add Enric as a maintainer MAINTAINERS: platform/chrome: remove myself as maintainer platform/chrome: don't report EC_MKBP_EVENT_SENSOR_FIFO as wakeup platform/chrome: straighten out cros_ec_get_{next,host}_event() error codes