apparmor: fix ptrace label match when matching stacked labels
Given a label with a profile stack of
A//&B or A//&C ...
A ptrace rule should be able to specify a generic trace pattern with
a rule like
ptrace trace A//&**,
however this is failing because while the correct label match routine
is called, it is being done post label decomposition so it is always
being done against a profile instead of the stacked label.
To fix this refactor the cross check to pass the full peer label in to
the label_match.
Fixes: 290f458a4f
("apparmor: allow ptrace checks to be finer grained than just capability")
Cc: Stable <stable@vger.kernel.org>
Reported-by: Matthew Garrett <mjg59@google.com>
Tested-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
parent
c92a9a461d
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@ -133,6 +133,9 @@ extern struct aa_perms allperms;
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#define xcheck_labels_profiles(L1, L2, FN, args...) \
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xcheck_ns_labels((L1), (L2), xcheck_ns_profile_label, (FN), args)
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#define xcheck_labels(L1, L2, P, FN1, FN2) \
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xcheck(fn_for_each((L1), (P), (FN1)), fn_for_each((L2), (P), (FN2)))
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void aa_perm_mask_to_str(char *str, const char *chrs, u32 mask);
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void aa_audit_perm_names(struct audit_buffer *ab, const char **names, u32 mask);
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@ -64,40 +64,48 @@ static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
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FLAGS_NONE, GFP_ATOMIC);
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}
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/* assumes check for PROFILE_MEDIATES is already done */
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/* TODO: conditionals */
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static int profile_ptrace_perm(struct aa_profile *profile,
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struct aa_profile *peer, u32 request,
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struct aa_label *peer, u32 request,
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struct common_audit_data *sa)
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{
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struct aa_perms perms = { };
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/* need because of peer in cross check */
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if (profile_unconfined(profile) ||
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!PROFILE_MEDIATES(profile, AA_CLASS_PTRACE))
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return 0;
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aad(sa)->peer = &peer->label;
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aa_profile_match_label(profile, &peer->label, AA_CLASS_PTRACE, request,
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aad(sa)->peer = peer;
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aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request,
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&perms);
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aa_apply_modes_to_perms(profile, &perms);
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return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb);
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}
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static int cross_ptrace_perm(struct aa_profile *tracer,
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struct aa_profile *tracee, u32 request,
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static int profile_tracee_perm(struct aa_profile *tracee,
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struct aa_label *tracer, u32 request,
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struct common_audit_data *sa)
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{
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if (profile_unconfined(tracee) || unconfined(tracer) ||
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!PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE))
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return 0;
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return profile_ptrace_perm(tracee, tracer, request, sa);
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}
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static int profile_tracer_perm(struct aa_profile *tracer,
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struct aa_label *tracee, u32 request,
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struct common_audit_data *sa)
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{
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if (profile_unconfined(tracer))
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return 0;
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if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE))
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return xcheck(profile_ptrace_perm(tracer, tracee, request, sa),
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profile_ptrace_perm(tracee, tracer,
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request << PTRACE_PERM_SHIFT,
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sa));
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/* policy uses the old style capability check for ptrace */
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if (profile_unconfined(tracer) || tracer == tracee)
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return profile_ptrace_perm(tracer, tracee, request, sa);
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/* profile uses the old style capability check for ptrace */
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if (&tracer->label == tracee)
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return 0;
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aad(sa)->label = &tracer->label;
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aad(sa)->peer = &tracee->label;
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aad(sa)->peer = tracee;
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aad(sa)->request = 0;
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aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 1);
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@ -115,10 +123,13 @@ static int cross_ptrace_perm(struct aa_profile *tracer,
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int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
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u32 request)
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{
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struct aa_profile *profile;
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u32 xrequest = request << PTRACE_PERM_SHIFT;
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DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
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return xcheck_labels_profiles(tracer, tracee, cross_ptrace_perm,
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request, &sa);
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return xcheck_labels(tracer, tracee, profile,
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profile_tracer_perm(profile, tracee, request, &sa),
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profile_tracee_perm(profile, tracer, xrequest, &sa));
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}
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