[PATCH v3 04/15] selinux: Refactor to remove bprm_secureexec hook
From: paul@paul-moore.com (Paul Moore)
Date: 2017-07-20 00:03:30
Also in:
linux-fsdevel, lkml
On Tue, Jul 18, 2017 at 6:25 PM, Kees Cook [off-list ref] wrote:
The SELinux bprm_secureexec hook can be merged with the bprm_set_creds hook since it's dealing with the same information, and all of the details are finalized during the first call to the bprm_set_creds hook via prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored via bprm->called_set_creds). Here, the test can just happen at the end of the bprm_set_creds hook, and the bprm_secureexec hook can be dropped. Cc: Paul Moore <paul@paul-moore.com> Cc: Stephen Smalley <redacted> Signed-off-by: Kees Cook <redacted> --- security/selinux/hooks.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-)
This seems reasonable in the context of the other changes. Stephen just posted an AT_SECURE test for the selinux-testsuite on the SELinux mailing list, it would be nice to ensure that this patchset doesn't run afoul of that. Acked-by: Paul Moore <paul@paul-moore.com>
quoted hunk ↗ jump to hunk
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 0f1450a06b02..18038f73a2f7 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c@@ -2413,30 +2413,17 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) /* Clear any possibly unsafe personality bits on exec: */ bprm->per_clear |= PER_CLEAR_ON_SETID; - } - - return 0; -} - -static int selinux_bprm_secureexec(struct linux_binprm *bprm) -{ - const struct task_security_struct *tsec = current_security(); - u32 sid, osid; - int atsecure = 0; - - sid = tsec->sid; - osid = tsec->osid; - if (osid != sid) { /* Enable secure mode for SIDs transitions unless the noatsecure permission is granted between the two SIDs, i.e. ahp returns 0. */ - atsecure = avc_has_perm(osid, sid, - SECCLASS_PROCESS, - PROCESS__NOATSECURE, NULL); + rc = avc_has_perm(old_tsec->sid, new_tsec->sid, + SECCLASS_PROCESS, PROCESS__NOATSECURE, + NULL); + bprm->secureexec |= !!rc; } - return !!atsecure; + return 0; } static int match_file(const void *p, struct file *file, unsigned fd)@@ -6151,7 +6138,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(bprm_set_creds, selinux_bprm_set_creds), LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds), LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds), - LSM_HOOK_INIT(bprm_secureexec, selinux_bprm_secureexec), LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security), LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security), --2.7.4
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