lwn.git/security/selinux/ss/conditional.c, branch docs-6.8-2

selinux: drop avtab_search()

2023-07-19T15:04:28+00:00

avtab_search() shares the same logic with avtab_search_node(), except that it returns, if found, a pointer to the struct avtab_node member datum instead of the node itself. Since the member is an embedded struct, and not a pointer, the returned value of avtab_search() and avtab_search_node() will always in unison either be NULL or non-NULL. Drop avtab_search() and replace its calls by avtab_search_node() to deduplicate logic and adopt the only caller caring for the type of the returned value accordingly. Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore

selinux: avoid bool as identifier name

2023-06-05T21:04:01+00:00

Avoid using the identifier `bool` to improve support with future C standards. C23 is about to make `bool` a predefined macro (see N2654). Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore

Merge tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2022-03-22T03:47:54+00:00

Pull selinux updates from Paul Moore: "We've got a number of SELinux patches queued up, the highlights are: - Fixup the security_fs_context_parse_param() LSM hook so it executes all of the LSM hook implementations unless a serious error occurs. We also correct the SELinux hook implementation so that it returns zero on success. - In addition to a few SELinux mount option parsing fixes, we simplified the parsing by moving it earlier in the process. The logic was that it was unlikely an admin/user would use the new mount API and not have the policy loaded before passing the SELinux options. - Properly fixed the LSM/SELinux/SCTP hooks with the addition of the security_sctp_assoc_established() hook. This work was done in conjunction with the netdev folks and should complete the move of the SCTP labeling from the endpoints to the associations. - Fixed a variety of sparse warnings caused by changes in the "__rcu" markings of some core kernel structures. - Ensure we access the superblock's LSM security blob using the stacking-safe accessors. - Added the ability for the kernel to always allow FIOCLEX and FIONCLEX if the "ioctl_skip_cloexec" policy capability is specified. - Various constifications improvements, type casting improvements, additional return value checks, and dead code/parameter removal. - Documentation fixes" * tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (23 commits) selinux: shorten the policy capability enum names docs: fix 'make htmldocs' warning in SCTP.rst selinux: allow FIOCLEX and FIONCLEX with policy capability selinux: use correct type for context length selinux: drop return statement at end of void functions security: implement sctp_assoc_established hook in selinux security: add sctp_assoc_established hook selinux: parse contexts for mount options early selinux: various sparse fixes selinux: try to use preparsed sid before calling parse_sid() selinux: Fix selinux_sb_mnt_opts_compat() LSM: general protection fault in legacy_parse_param selinux: fix a type cast problem in cred_init_security() selinux: drop unused macro selinux: simplify cred_init_security selinux: do not discard const qualifier in cast selinux: drop unused parameter of avtab_insert_node selinux: drop cast to same type selinux: enclose macro arguments in parenthesis selinux: declare name parameter of hash_eval const ...

selinux: drop return statement at end of void functions

2022-02-18T15:42:12+00:00

Those return statements at the end of a void function are redundant. Reported by clang-tidy [readability-redundant-control-flow] Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore

selinux: fix double free of cond_list on error paths

2022-02-02T16:02:10+00:00

On error path from cond_read_list() and duplicate_policydb_cond_list() the cond_list_destroy() gets called a second time in caller functions, resulting in NULL pointer deref. Fix this by resetting the cond_list_len to 0 in cond_list_destroy(), making subsequent calls a noop. Also consistently reset the cond_list pointer to NULL after freeing. Cc: stable@vger.kernel.org Signed-off-by: Vratislav Bendel [PM: fix line lengths in the description] Signed-off-by: Paul Moore

selinux: constify some avtab function arguments

2021-05-11T01:35:02+00:00

This makes the code a bit easier to reason about. Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore

selinux: simplify duplicate_policydb_cond_list() by using kmemdup()

2021-05-11T01:31:58+00:00

We can do the allocation + copying of expr.nodes in one go using kmemdup(). Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore

selinux: fix cond_list corruption when changing booleans

2021-04-02T15:46:55+00:00

Currently, duplicate_policydb_cond_list() first copies the whole conditional avtab and then tries to link to the correct entries in cond_dup_av_list() using avtab_search(). However, since the conditional avtab may contain multiple entries with the same key, this approach often fails to find the right entry, potentially leading to wrong rules being activated/deactivated when booleans are changed. To fix this, instead start with an empty conditional avtab and add the individual entries one-by-one while building the new av_lists. This approach leads to the correct result, since each entry is present in the av_lists exactly once. The issue can be reproduced with Fedora policy as follows: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True # setsebool ftpd_anon_write=off ftpd_connect_all_unreserved=off ftpd_connect_db=off ftpd_full_access=off On fixed kernels, the sesearch output is the same after the setsebool command: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True While on the broken kernels, it will be different: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True While there, also simplify the computation of nslots. This changes the nslots values for nrules 2 or 3 to just two slots instead of 4, which makes the sequence more consistent. Cc: stable@vger.kernel.org Fixes: c7c556f1e81b ("selinux: refactor changing booleans") Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore

selinux: fix memdup.cocci warnings

2020-08-20T12:39:05+00:00

Use kmemdup rather than duplicating its implementation Generated by: scripts/coccinelle/api/memdup.cocci Fixes: c7c556f1e81b ("selinux: refactor changing booleans") CC: Stephen Smalley Signed-off-by: kernel test robot Signed-off-by: Julia Lawall Acked-by: Stephen Smalley Signed-off-by: Paul Moore

selinux: refactor changing booleans

2020-08-18T01:00:33+00:00

Refactor the logic for changing SELinux policy booleans in a similar manner to the refactoring of policy load, thereby reducing the size of the critical section when the policy write-lock is held and making it easier to convert the policy rwlock to RCU in the future. Instead of directly modifying the policydb in place, modify a copy and then swap it into place through a single pointer update. Only fully copy the portions of the policydb that are affected by boolean changes to avoid the full cost of a deep policydb copy. Introduce another level of indirection for the sidtab since changing booleans does not require updating the sidtab, unlike policy load. While we are here, create a common helper for notifying other kernel components and userspace of a policy change and call it from both security_set_bools() and selinux_policy_commit(). Based on an old (2004) patch by Kaigai Kohei [1] to convert the policy rwlock to RCU that was deferred at the time since it did not significantly improve performance and introduced complexity. Peter Enderborg later submitted a patch series to convert to RCU [2] that would have made changing booleans a much more expensive operation by requiring a full policydb_write();policydb_read(); sequence to deep copy the entire policydb and also had concerns regarding atomic allocations. This change is now simplified by the earlier work to encapsulate policy state in the selinux_policy struct and to refactor policy load. After this change, the last major obstacle to converting the policy rwlock to RCU is likely the sidtab live convert support. [1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/ [2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/ Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore