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2017-11-28selinux: ensure the context is NUL terminated in security_context_to_sid_core()Paul Moore1-10/+8
The syzbot/syzkaller automated tests found a problem in security_context_to_sid_core() during early boot (before we load the SELinux policy) where we could potentially feed context strings without NUL terminators into the strcmp() function. We already guard against this during normal operation (after the SELinux policy has been loaded) by making a copy of the context strings and explicitly adding a NUL terminator to the end. The patch extends this protection to the early boot case (no loaded policy) by moving the context copy earlier in security_context_to_sid_core(). Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Reviewed-By: William Roberts <william.c.roberts@intel.com>
2017-10-16selinux: remove extraneous initialization of slots_used and max_chain_lenColin Ian King1-1/+1
Variables slots_used and max_chain_len are being initialized to zero twice. Remove the second set of initializations in the for loop. Cleans up the clang warnings: Value stored to 'slots_used' is never read Value stored to 'max_chain_len' is never read Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-10-16selinux: remove redundant assignment to lenColin Ian King1-1/+0
The variable len is being set to zero and this value is never being read since len is being set to a different value just a few lines later. Remove this redundant assignment. Cleans up clang warning: Value stored to 'len' is never read Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-09-20selinux: Use kmem_cache for hashtab_nodeKyeongdon Kim3-2/+23
During random test as own device to check slub account, we found some slack memory from hashtab_node(kmalloc-64). By using kzalloc(), middle of test result like below: allocated size 240768 request size 45144 slack size 195624 allocation count 3762 So, we want to use kmem_cache_zalloc() and that can reduce memory size 52byte(slack size/alloc count) per each struct. Signed-off-by: Kyeongdon Kim <kyeongdon.kim@lge.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-08-17selinux: update my email addressStephen Smalley19-19/+19
Update my email address since epoch.ncsc.mil no longer exists. MAINTAINERS and CREDITS are already correct. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-08-02selinux: Generalize support for NNP/nosuid SELinux domain transitionsStephen Smalley1-1/+6
As systemd ramps up enabling NNP (NoNewPrivileges) for system services, it is increasingly breaking SELinux domain transitions for those services and their descendants. systemd enables NNP not only for services whose unit files explicitly specify NoNewPrivileges=yes but also for services whose unit files specify any of the following options in combination with running without CAP_SYS_ADMIN (e.g. specifying User= or a CapabilityBoundingSet= without CAP_SYS_ADMIN): SystemCallFilter=, SystemCallArchitectures=, RestrictAddressFamilies=, RestrictNamespaces=, PrivateDevices=, ProtectKernelTunables=, ProtectKernelModules=, MemoryDenyWriteExecute=, or RestrictRealtime= as per the systemd.exec(5) man page. The end result is bad for the security of both SELinux-disabled and SELinux-enabled systems. Packagers have to turn off these options in the unit files to preserve SELinux domain transitions. For users who choose to disable SELinux, this means that they miss out on at least having the systemd-supported protections. For users who keep SELinux enabled, they may still be missing out on some protections because it isn't necessarily guaranteed that the SELinux policy for that service provides the same protections in all cases. commit 7b0d0b40cd78 ("selinux: Permit bounded transitions under NO_NEW_PRIVS or NOSUID.") allowed bounded transitions under NNP in order to support limited usage for sandboxing programs. However, defining typebounds for all of the affected service domains is impractical to implement in policy, since typebounds requires us to ensure that each domain is allowed everything all of its descendant domains are allowed, and this has to be repeated for the entire chain of domain transitions. There is no way to clone all allow rules from descendants to their ancestors in policy currently, and doing so would be undesirable even if it were practical, as it requires leaking permissions to objects and operations into ancestor domains that could weaken their own security in order to allow them to the descendants (e.g. if a descendant requires execmem permission, then so do all of its ancestors; if a descendant requires execute permission to a file, then so do all of its ancestors; if a descendant requires read to a symbolic link or temporary file, then so do all of its ancestors...). SELinux domains are intentionally not hierarchical / bounded in this manner normally, and making them so would undermine their protections and least privilege. We have long had a similar tension with SELinux transitions and nosuid mounts, albeit not as severe. Users often have had to choose between retaining nosuid on a mount and allowing SELinux domain transitions on files within those mounts. This likewise leads to unfortunate tradeoffs in security. Decouple NNP/nosuid from SELinux transitions, so that we don't have to make a choice between them. Introduce a nnp_nosuid_transition policy capability that enables transitions under NNP/nosuid to be based on a permission (nnp_transition for NNP; nosuid_transition for nosuid) between the old and new contexts in addition to the current support for bounded transitions. Domain transitions can then be allowed in policy without requiring the parent to be a strict superset of all of its children. With this change, systemd unit files can be left unmodified from upstream. SELinux-disabled and SELinux-enabled users will benefit from retaining any of the systemd-provided protections. SELinux policy will only need to be adapted to enable the new policy capability and to allow the new permissions between domain pairs as appropriate. NB: Allowing nnp_transition between two contexts opens up the potential for the old context to subvert the new context by installing seccomp filters before the execve. Allowing nosuid_transition between two contexts opens up the potential for a context transition to occur on a file from an untrusted filesystem (e.g. removable media or remote filesystem). Use with care. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-06-09selinux: use kmem_cache for ebitmapJunil Lee3-6/+27
The allocated size for each ebitmap_node is 192byte by kzalloc(). Then, ebitmap_node size is fixed, so it's possible to use only 144byte for each object by kmem_cache_zalloc(). It can reduce some dynamic allocation size. Signed-off-by: Junil Lee <junil0814.lee@lge.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: Add IB Port SMP access vectorDaniel Jurgens1-0/+41
Add a type for Infiniband ports and an access vector for subnet management packets. Implement the ib_port_smp hook to check that the caller has permission to send and receive SMPs on the end port specified by the device name and port. Add interface to query the SID for a IB port, which walks the IB_PORT ocontexts to find an entry for the given name and port. Signed-off-by: Daniel Jurgens <danielj@mellanox.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: Implement Infiniband PKey "Access" access vectorDaniel Jurgens1-0/+40
Add a type and access vector for PKeys. Implement the ib_pkey_access hook to check that the caller has permission to access the PKey on the given subnet prefix. Add an interface to get the PKey SID. Walk the PKey ocontexts to find an entry for the given subnet prefix and pkey. Signed-off-by: Daniel Jurgens <danielj@mellanox.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: Create policydb version for Infiniband supportDaniel Jurgens2-23/+116
Support for Infiniband requires the addition of two new object contexts, one for infiniband PKeys and another IB Ports. Added handlers to read and write the new ocontext types when reading or writing a binary policy representation. Signed-off-by: Daniel Jurgens <danielj@mellanox.com> Reviewed-by: Eli Cohen <eli@mellanox.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: log policy capability state when a policy is loadedStephen Smalley1-0/+23
Log the state of SELinux policy capabilities when a policy is loaded. For each policy capability known to the kernel, log the policy capability name and the value set in the policy. For policy capabilities that are set in the loaded policy but unknown to the kernel, log the policy capability index, since this is the only information presently available in the policy. Sample output with a policy created with a new capability defined that is not known to the kernel: SELinux: policy capability network_peer_controls=1 SELinux: policy capability open_perms=1 SELinux: policy capability extended_socket_class=1 SELinux: policy capability always_check_network=0 SELinux: policy capability cgroup_seclabel=0 SELinux: unknown policy capability 5 Resolves: https://github.com/SELinuxProject/selinux-kernel/issues/32 Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: Return an error code only as a constant in sidtab_insert()Markus Elfring1-17/+10
* Return an error code without storing it in an intermediate variable. * Delete the local variable "rc" and the jump label "out" which became unnecessary with this refactoring. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-05-23selinux: Return directly after a failed memory allocation in policydb_index()Markus Elfring1-10/+5
Replace five goto statements (and previous variable assignments) by direct returns after a memory allocation failure in this function. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-31selinux: Fix an uninitialized variable bugDan Carpenter1-1/+1
We removed this initialization as a cleanup but it is probably required. The concern is that "nel" can be zero. I'm not an expert on SELinux code but I think it looks possible to write an SELinux policy which triggers this bug. GCC doesn't catch this, but my static checker does. Fixes: 9c312e79d6af ("selinux: Delete an unnecessary variable initialisation in range_read()") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Remove unnecessary check of array base in selinux_set_mapping()Matthias Kaehlcke1-1/+1
'perms' will never be NULL since it isn't a plain pointer but an array of u32 values. This fixes the following warning when building with clang: security/selinux/ss/services.c:158:16: error: address of array 'p_in->perms' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion] while (p_in->perms && p_in->perms[k]) { Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Adjust two checks for null pointersMarkus Elfring1-2/+2
The script "checkpatch.pl" pointed information out like the following. Comparison to NULL could be written !… Thus fix affected source code places. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Use kmalloc_array() in sidtab_init()Markus Elfring1-1/+1
A multiplication for the size determination of a memory allocation indicated that an array data structure should be processed. Thus use the corresponding function "kmalloc_array". This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in roles_init()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in perm_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in common_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in class_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in role_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in type_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in user_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Improve another size determination in sens_read()Markus Elfring1-1/+1
Replace the specification of a data type by a pointer dereference as the parameter for the operator "sizeof" to make the corresponding size determination a bit safer according to the Linux coding style convention. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in sens_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-29selinux: Return directly after a failed kzalloc() in cat_read()Markus Elfring1-2/+1
Return directly after a call of the function "kzalloc" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Delete an unnecessary variable initialisation in range_read()Markus Elfring1-1/+1
The local variable "rt" will be set to an appropriate pointer a bit later. Thus omit the explicit initialisation at the beginning which became unnecessary with a previous update step. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Return directly after a failed next_entry() in range_read()Markus Elfring1-1/+1
Return directly after a call of the function "next_entry" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Delete an unnecessary variable assignment in filename_trans_read()Markus Elfring1-1/+0
The local variable "ft" was set to a null pointer despite of an immediate reassignment. Thus remove this statement from the beginning of a loop. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: One function call less in genfs_read() after null pointer detectionMarkus Elfring1-2/+3
Call the function "kfree" at the end only after it was determined that the local variable "newgenfs" contained a non-null pointer. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Return directly after a failed next_entry() in genfs_read()Markus Elfring1-1/+1
Return directly after a call of the function "next_entry" failed at the beginning. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Delete an unnecessary return statement in policydb_destroy()Markus Elfring1-2/+0
The script "checkpatch.pl" pointed information out like the following. WARNING: void function return statements are not generally useful Thus remove such a statement in the affected function. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Use kcalloc() in policydb_index()Markus Elfring1-9/+9
Multiplications for the size determination of memory allocations indicated that array data structures should be processed. Thus use the corresponding function "kcalloc". This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Adjust four checks for null pointersMarkus Elfring1-4/+4
The script "checkpatch.pl" pointed information out like the following. Comparison to NULL could be written !… Thus fix affected source code places. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Use kmalloc_array() in hashtab_create()Markus Elfring1-1/+1
A multiplication for the size determination of a memory allocation indicated that an array data structure should be processed. Thus use the corresponding function "kmalloc_array". This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Improve size determinations in four functionsMarkus Elfring1-4/+4
Replace the specification of data structures by pointer dereferences as the parameter for the operator "sizeof" to make the corresponding size determination a bit safer. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Delete an unnecessary return statement in cond_compute_av()Markus Elfring1-1/+0
The script "checkpatch.pl" pointed information out like the following. WARNING: void function return statements are not generally useful Thus remove such a statement in the affected function. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-23selinux: Use kmalloc_array() in cond_init_bool_indexes()Markus Elfring1-2/+3
* A multiplication for the size determination of a memory allocation indicated that an array data structure should be processed. Thus use the corresponding function "kmalloc_array". This issue was detected by using the Coccinelle software. * Replace the specification of a data type by a pointer dereference to make the corresponding size determination a bit safer according to the Linux coding style convention. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-03-02selinux: wrap cgroup seclabel support with its own policy capabilityStephen Smalley1-0/+4
commit 1ea0ce40690dff38935538e8dab7b12683ded0d3 ("selinux: allow changing labels for cgroupfs") broke the Android init program, which looks up security contexts whenever creating directories and attempts to assign them via setfscreatecon(). When creating subdirectories in cgroup mounts, this would previously be ignored since cgroup did not support userspace setting of security contexts. However, after the commit, SELinux would attempt to honor the requested context on cgroup directories and fail due to permission denial. Avoid breaking existing userspace/policy by wrapping this change with a conditional on a new cgroup_seclabel policy capability. This preserves existing behavior until/unless a new policy explicitly enables this capability. Reported-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-02-27lib/vsprintf.c: remove %Z supportAlexey Dobriyan2-2/+2
Now that %z is standartised in C99 there is no reason to support %Z. Unlike %L it doesn't even make format strings smaller. Use BUILD_BUG_ON in a couple ATM drivers. In case anyone didn't notice lib/vsprintf.o is about half of SLUB which is in my opinion is quite an achievement. Hopefully this patch inspires someone else to trim vsprintf.c more. Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-09selinux: support distinctions among all network address familiesStephen Smalley1-0/+3
Extend SELinux to support distinctions among all network address families implemented by the kernel by defining new socket security classes and mapping to them. Otherwise, many sockets are mapped to the generic socket class and are indistinguishable in policy. This has come up previously with regard to selectively allowing access to bluetooth sockets, and more recently with regard to selectively allowing access to AF_ALG sockets. Guido Trentalancia submitted a patch that took a similar approach to add only support for distinguishing AF_ALG sockets, but this generalizes his approach to handle all address families implemented by the kernel. Socket security classes are also added for ICMP and SCTP sockets. Socket security classes were not defined for AF_* values that are reserved but unimplemented in the kernel, e.g. AF_NETBEUI, AF_SECURITY, AF_ASH, AF_ECONET, AF_SNA, AF_WANPIPE. Backward compatibility is provided by only enabling the finer-grained socket classes if a new policy capability is set in the policy; older policies will behave as before. The legacy redhat1 policy capability that was only ever used in testing within Fedora for ptrace_child is reclaimed for this purpose; as far as I can tell, this policy capability is not enabled in any supported distro policy. Add a pair of conditional compilation guards to detect when new AF_* values are added so that we can update SELinux accordingly rather than having to belatedly update it long after new address families are introduced. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-10-10Merge branch 'printk-cleanups'Linus Torvalds1-2/+2
Merge my system logging cleanups, triggered by the broken '\n' patches. The line continuation handling has been broken basically forever, and the code to handle the system log records was both confusing and dubious. And it would do entirely the wrong thing unless you always had a terminating newline, partly because it couldn't actually see whether a message was marked KERN_CONT or not (but partly because the LOG_CONT handling in the recording code was rather confusing too). This re-introduces a real semantically meaningful KERN_CONT, and fixes the few places I noticed where it was missing. There are probably more missing cases, since KERN_CONT hasn't actually had any semantic meaning for at least four years (other than the checkpatch meaning of "no log level necessary, this is a continuation line"). This also allows the combination of KERN_CONT and a log level. In that case the log level will be ignored if the merging with a previous line is successful, but if a new record is needed, that new record will now get the right log level. That also means that you can at least in theory combine KERN_CONT with the "pr_info()" style helpers, although any use of pr_fmt() prefixing would make that just result in a mess, of course (the prefix would end up in the middle of a continuing line). * printk-cleanups: printk: make reading the kernel log flush pending lines printk: re-organize log_output() to be more legible printk: split out core logging code into helper function printk: reinstate KERN_CONT for printing continuation lines
2016-10-09printk: reinstate KERN_CONT for printing continuation linesLinus Torvalds1-2/+2
Long long ago the kernel log buffer was a buffered stream of bytes, very much like stdio in user space. It supported log levels by scanning the stream and noticing the log level markers at the beginning of each line, but if you wanted to print a partial line in multiple chunks, you just did multiple printk() calls, and it just automatically worked. Except when it didn't, and you had very confusing output when different lines got all mixed up with each other. Then you got fragment lines mixing with each other, or with non-fragment lines, because it was traditionally impossible to tell whether a printk() call was a continuation or not. To at least help clarify the issue of continuation lines, we added a KERN_CONT marker back in 2007 to mark continuation lines: 474925277671 ("printk: add KERN_CONT annotation"). That continuation marker was initially an empty string, and didn't actuall make any semantic difference. But it at least made it possible to annotate the source code, and have check-patch notice that a printk() didn't need or want a log level marker, because it was a continuation of a previous line. To avoid the ambiguity between a continuation line that had that KERN_CONT marker, and a printk with no level information at all, we then in 2009 made KERN_CONT be a real log level marker which meant that we could now reliably tell the difference between the two cases. 5fd29d6ccbc9 ("printk: clean up handling of log-levels and newlines") and we could take advantage of that to make sure we didn't mix up continuation lines with lines that just didn't have any loglevel at all. Then, in 2012, the kernel log buffer was changed to be a "record" based log, where each line was a record that has a loglevel and a timestamp. You can see the beginning of that conversion in commits e11fea92e13f ("kmsg: export printk records to the /dev/kmsg interface") 7ff9554bb578 ("printk: convert byte-buffer to variable-length record buffer") with a number of follow-up commits to fix some painful fallout from that conversion. Over all, it took a couple of months to sort out most of it. But the upside was that you could have concurrent readers (and writers) of the kernel log and not have lines with mixed output in them. And one particular pain-point for the record-based kernel logging was exactly the fragmentary lines that are generated in smaller chunks. In order to still log them as one recrod, the continuation lines need to be attached to the previous record properly. However the explicit continuation record marker that is actually useful for this exact case was actually removed in aroundm the same time by commit 61e99ab8e35a ("printk: remove the now unnecessary "C" annotation for KERN_CONT") due to the incorrect belief that KERN_CONT wasn't meaningful. The ambiguity between "is this a continuation line" or "is this a plain printk with no log level information" was reintroduced, and in fact became an even bigger pain point because there was now the whole record-level merging of kernel messages going on. This patch reinstates the KERN_CONT as a real non-empty string marker, so that the ambiguity is fixed once again. But it's not a plain revert of that original removal: in the four years since we made KERN_CONT an empty string again, not only has the format of the log level markers changed, we've also had some usage changes in this area. For example, some ACPI code seems to use KERN_CONT _together_ with a log level, and now uses both the KERN_CONT marker and (for example) a KERN_INFO marker to show that it's an informational continuation of a line. Which is actually not a bad idea - if the continuation line cannot be attached to its predecessor, without the log level information we don't know what log level to assign to it (and we traditionally just assigned it the default loglevel). So having both a log level and the KERN_CONT marker is not necessarily a bad idea, but it does mean that we need to actually iterate over potentially multiple markers, rather than just a single one. Also, since KERN_CONT was still conceptually needed, and encouraged, but didn't actually _do_ anything, we've also had the reverse problem: rather than having too many annotations it has too few, and there is bit rot with code that no longer marks the continuation lines with the KERN_CONT marker. So this patch not only re-instates the non-empty KERN_CONT marker, it also fixes up the cases of bit-rot I noticed in my own logs. There are probably other cases where KERN_CONT will be needed to be added, either because it is new code that never dealt with the need for KERN_CONT, or old code that has bitrotted without anybody noticing. That said, we should strive to avoid the need for KERN_CONT. It does result in real problems for logging, and should generally not be seen as a good feature. If we some day can get rid of the feature entirely, because nobody does any fragmented printk calls, that would be lovely. But until that point, let's at mark the code that relies on the hacky multi-fragment kernel printk's. Not only does it avoid the ambiguity, it also annotates code as "maybe this would be good to fix some day". (That said, particularly during single-threaded bootup, the downsides of KERN_CONT are very limited. Things get much hairier when you have multiple threads going on and user level reading and writing logs too). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-13selinux: fix error return code in policydb_read()Wei Yongjun1-0/+1
Fix to return error code -EINVAL from the error handling case instead of 0 (rc is overwrite to 0 when policyvers >= POLICYDB_VERSION_ROLETRANS), as done elsewhere in this function. Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> [PM: normalize "selinux" in patch subject, description line wrap] Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-30selinux: fix overflow and 0 length allocationsWilliam Roberts2-0/+5
Throughout the SELinux LSM, values taken from sepolicy are used in places where length == 0 or length == <saturated> matter, find and fix these. Signed-off-by: William Roberts <william.c.roberts@intel.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-29selinux: initialize structuresWilliam Roberts1-4/+4
libsepol pointed out an issue where its possible to have an unitialized jmp and invalid dereference, fix this. While we're here, zero allocate all the *_val_to_struct structures. Signed-off-by: William Roberts <william.c.roberts@intel.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-29selinux: detect invalid ebitmapWilliam Roberts1-0/+3
When count is 0 and the highbit is not zero, the ebitmap is not valid and the internal node is not allocated. This causes issues when routines, like mls_context_isvalid() attempt to use the ebitmap_for_each_bit() and ebitmap_node_get_bit() as they assume a highbit > 0 will have a node allocated. Signed-off-by: William Roberts <william.c.roberts@intel.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-06-09selinux: import NetLabel category bitmaps correctlyPaul Moore1-1/+1
The existing ebitmap_netlbl_import() code didn't correctly handle the case where the ebitmap_node was not aligned/sized to a power of two, this patch fixes this (on x86_64 ebitmap_node contains six bitmaps making a range of 0..383). Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-05-31selinux: Only apply bounds checking to source typesStephen Smalley1-48/+22
The current bounds checking of both source and target types requires allowing any domain that has access to the child domain to also have the same permissions to the parent, which is undesirable. Drop the target bounds checking. KaiGai Kohei originally removed all use of target bounds in commit 7d52a155e38d ("selinux: remove dead code in type_attribute_bounds_av()") but this was reverted in commit 2ae3ba39389b ("selinux: libsepol: remove dead code in check_avtab_hierarchy_callback()") because it would have required explicitly allowing the parent any permissions to the child that the child is allowed to itself. This change in contrast retains the logic for the case where both source and target types are bounded, thereby allowing access if the parent of the source is allowed the corresponding permissions to the parent of the target. Further, this change reworks the logic such that we only perform a single computation for each case and there is no ambiguity as to how to resolve a bounds violation. Under the new logic, if the source type and target types are both bounded, then the parent of the source type must be allowed the same permissions to the parent of the target type. If only the source type is bounded, then the parent of the source type must be allowed the same permissions to the target type. Examples of the new logic and comparisons with the old logic: 1. If we have: typebounds A B; then: allow B self:process <permissions>; will satisfy the bounds constraint iff: allow A self:process <permissions>; is also allowed in policy. Under the old logic, the allow rule on B satisfies the bounds constraint if any of the following three are allowed: allow A B:process <permissions>; or allow B A:process <permissions>; or allow A self:process <permissions>; However, either of the first two ultimately require the third to satisfy the bounds constraint under the old logic, and therefore this degenerates to the same result (but is more efficient - we only need to perform one compute_av call). 2. If we have: typebounds A B; typebounds A_exec B_exec; then: allow B B_exec:file <permissions>; will satisfy the bounds constraint iff: allow A A_exec:file <permissions>; is also allowed in policy. This is essentially the same as #1; it is merely included as an example of dealing with object types related to a bounded domain in a manner that satisfies the bounds relationship. Note that this approach is preferable to leaving B_exec unbounded and having: allow A B_exec:file <permissions>; in policy because that would allow B's entrypoints to be used to enter A. Similarly for _tmp or other related types. 3. If we have: typebounds A B; and an unbounded type T, then: allow B T:file <permissions>; will satisfy the bounds constraint iff: allow A T:file <permissions>; is allowed in policy. The old logic would have been identical for this example. 4. If we have: typebounds A B; and an unbounded domain D, then: allow D B:unix_stream_socket <permissions>; is not subject to any bounds constraints under the new logic because D is not bounded. This is desirable so that we can allow a domain to e.g. connectto a child domain without having to allow it to do the same to its parent. The old logic would have required: allow D A:unix_stream_socket <permissions>; to also be allowed in policy. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: re-wrapped description to appease checkpatch.pl] Signed-off-by: Paul Moore <paul@paul-moore.com>