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| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-03-22 21:46:24 +0100 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2020-05-20 21:45:31 +0200 |
| commit | b8bff599261c930630385ee21d3f98e7ce7d4843 (patch) | |
| tree | abe467d5124f1df78e2d2383068c90f518a16069 /security/selinux | |
| parent | exec: Teach prepare_exec_creds how exec treats uids & gids (diff) | |
| download | linux-b8bff599261c930630385ee21d3f98e7ce7d4843.tar.xz linux-b8bff599261c930630385ee21d3f98e7ce7d4843.zip | |
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
Today security_bprm_set_creds has several implementations:
apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds,
smack_bprm_set_creds, and tomoyo_bprm_set_creds.
Except for cap_bprm_set_creds they all test bprm->called_set_creds and
return immediately if it is true. The function cap_bprm_set_creds
ignores bprm->calld_sed_creds entirely.
Create a new LSM hook security_bprm_creds_for_exec that is called just
before prepare_binprm in __do_execve_file, resulting in a LSM hook
that is called exactly once for the entire of exec. Modify the bits
of security_bprm_set_creds that only want to be called once per exec
into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds
behind.
Remove bprm->called_set_creds all of it's former users have been moved
to security_bprm_creds_for_exec.
Add or upate comments a appropriate to bring them up to date and
to reflect this change.
Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'security/selinux')
| -rw-r--r-- | security/selinux/hooks.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 0b4e32161b77..718345dd76bb 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2286,7 +2286,7 @@ static int check_nnp_nosuid(const struct linux_binprm *bprm, return -EACCES; } -static int selinux_bprm_set_creds(struct linux_binprm *bprm) +static int selinux_bprm_creds_for_exec(struct linux_binprm *bprm) { const struct task_security_struct *old_tsec; struct task_security_struct *new_tsec; @@ -2297,8 +2297,6 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) /* SELinux context only depends on initial program or script and not * the script interpreter */ - if (bprm->called_set_creds) - return 0; old_tsec = selinux_cred(current_cred()); new_tsec = selinux_cred(bprm->cred); @@ -6385,7 +6383,7 @@ static int selinux_setprocattr(const char *name, void *value, size_t size) /* Permission checking based on the specified context is performed during the actual operation (execve, open/mkdir/...), when we know the full context of the - operation. See selinux_bprm_set_creds for the execve + operation. See selinux_bprm_creds_for_exec for the execve checks and may_create for the file creation checks. The operation will then fail if the context is not permitted. */ tsec = selinux_cred(new); @@ -6914,7 +6912,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(netlink_send, selinux_netlink_send), - LSM_HOOK_INIT(bprm_set_creds, selinux_bprm_set_creds), + LSM_HOOK_INIT(bprm_creds_for_exec, selinux_bprm_creds_for_exec), LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds), LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds), |