[PATCH] apparmor: Fix change_onexec when called from a confined task

From: John Johansen
Date: Tue Mar 27 2012 - 07:14:42 EST

Fix failure in aa_change_onexec api when the request is made from a confined
task. This failure was caused by two problems

The AA_MAY_ONEXEC perm was not being mapped correctly for this case.

The executable name was being checked as second time instead of using the
requested onexec profile name, which may not be the same as the exec
profile name. This mistake can not be exploited to grant extra permission
because of the above flaw where the ONEXEC permission was not being mapped
so it will not be granted.

BugLink: http://bugs.launchpad.net/bugs/963756

Signed-off-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
security/apparmor/domain.c | 3 ++-
security/apparmor/file.c | 2 ++
2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 7c69599..6327685 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -410,7 +410,8 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
* exec\0change_profile
state = aa_dfa_null_transition(profile->file.dfa, state);
- cp = change_profile_perms(profile, cxt->onexec->ns, name,
+ cp = change_profile_perms(profile, cxt->onexec->ns,
+ cxt->onexec->base.name,
AA_MAY_ONEXEC, state);

if (!(cp.allow & AA_MAY_ONEXEC))
diff --git a/security/apparmor/file.c b/security/apparmor/file.c
index 3022c0f..5d176f2 100644
--- a/security/apparmor/file.c
+++ b/security/apparmor/file.c
@@ -215,6 +215,8 @@ static struct file_perms compute_perms(struct aa_dfa *dfa, unsigned int state,
/* change_profile wasn't determined by ownership in old mapping */
if (ACCEPT_TABLE(dfa)[state] & 0x80000000)
perms.allow |= AA_MAY_CHANGE_PROFILE;
+ if (ACCEPT_TABLE(dfa)[state] & 0x40000000)
+ perms.allow |= AA_MAY_ONEXEC;

return perms;

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