linux/security
Ondrej Mosnacek d8f5f0ea5b selinux: fix cond_list corruption when changing booleans
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: c7c556f1e8 ("selinux: refactor changing booleans")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-04-02 11:46:55 -04:00
..
apparmor apparmor: remove duplicate macro list_entry_is_head() 2020-12-15 22:46:19 -08:00
bpf bpf: Implement task local storage 2020-11-06 08:08:37 -08:00
integrity EFI updates collected by Ard Biesheuvel: 2020-12-24 12:40:07 -08:00
keys Networking updates for 5.11 2020-12-15 13:22:29 -08:00
loadpin LSM: Add "contents" flag to kernel_read_file hook 2020-10-05 13:37:03 +02:00
lockdown Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2020-06-02 17:36:24 -07:00
safesetid LSM: SafeSetID: Fix warnings reported by test bot 2020-10-13 09:17:36 -07:00
selinux selinux: fix cond_list corruption when changing booleans 2021-04-02 11:46:55 -04:00
smack Provide a fix for the incorrect handling of privilege 2020-12-24 14:08:43 -08:00
tomoyo tomoyo: Fix typo in comments. 2020-12-06 13:44:57 +09:00
yama task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
commoncap.c vfs: move cap_convert_nscap() call into vfs_setxattr() 2020-12-14 15:26:13 +01:00
device_cgroup.c device_cgroup: Fix RCU list debugging warning 2020-08-20 11:25:03 -07:00
inode.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
Kconfig Replace HTTP links with HTTPS ones: security 2020-08-06 12:00:05 -07:00
Kconfig.hardening security: allow using Clang's zero initialization for stack variables 2020-06-16 02:06:23 -07:00
lsm_audit.c audit/stable-5.11 PR 20201214 2020-12-16 10:54:03 -08:00
Makefile device_cgroup: Cleanup cgroup eBPF device filter code 2020-04-13 14:41:54 -04:00
min_addr.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
security.c security: add inode_init_security_anon() LSM hook 2021-01-14 17:28:24 -05:00