From 0dda0b3fb255048a221f736c8a2a24c674da8bf3 Mon Sep 17 00:00:00 2001 From: John Johansen Date: Fri, 8 Dec 2017 17:43:18 -0800 Subject: 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: 290f458a4f16 ("apparmor: allow ptrace checks to be finer grained than just capability") Cc: Stable Reported-by: Matthew Garrett Tested-by: Matthew Garrett Signed-off-by: John Johansen --- security/apparmor/include/perms.h | 3 +++ security/apparmor/ipc.c | 53 +++++++++++++++++++++++---------------- 2 files changed, 35 insertions(+), 21 deletions(-) diff --git a/security/apparmor/include/perms.h b/security/apparmor/include/perms.h index 2b27bb79aec4..d7b7e7115160 100644 --- a/security/apparmor/include/perms.h +++ b/security/apparmor/include/perms.h @@ -133,6 +133,9 @@ extern struct aa_perms allperms; #define xcheck_labels_profiles(L1, L2, FN, args...) \ xcheck_ns_labels((L1), (L2), xcheck_ns_profile_label, (FN), args) +#define xcheck_labels(L1, L2, P, FN1, FN2) \ + xcheck(fn_for_each((L1), (P), (FN1)), fn_for_each((L2), (P), (FN2))) + void aa_perm_mask_to_str(char *str, const char *chrs, u32 mask); void aa_audit_perm_names(struct audit_buffer *ab, const char **names, u32 mask); diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c index 7ca0032e7ba9..b40678f3c1d5 100644 --- a/security/apparmor/ipc.c +++ b/security/apparmor/ipc.c @@ -64,40 +64,48 @@ static void audit_ptrace_cb(struct audit_buffer *ab, void *va) FLAGS_NONE, GFP_ATOMIC); } +/* assumes check for PROFILE_MEDIATES is already done */ /* TODO: conditionals */ static int profile_ptrace_perm(struct aa_profile *profile, - struct aa_profile *peer, u32 request, - struct common_audit_data *sa) + struct aa_label *peer, u32 request, + struct common_audit_data *sa) { struct aa_perms perms = { }; - /* need because of peer in cross check */ - if (profile_unconfined(profile) || - !PROFILE_MEDIATES(profile, AA_CLASS_PTRACE)) - return 0; - - aad(sa)->peer = &peer->label; - aa_profile_match_label(profile, &peer->label, AA_CLASS_PTRACE, request, + aad(sa)->peer = peer; + aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request, &perms); aa_apply_modes_to_perms(profile, &perms); return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb); } -static int cross_ptrace_perm(struct aa_profile *tracer, - struct aa_profile *tracee, u32 request, - struct common_audit_data *sa) +static int profile_tracee_perm(struct aa_profile *tracee, + struct aa_label *tracer, u32 request, + struct common_audit_data *sa) { + if (profile_unconfined(tracee) || unconfined(tracer) || + !PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE)) + return 0; + + return profile_ptrace_perm(tracee, tracer, request, sa); +} + +static int profile_tracer_perm(struct aa_profile *tracer, + struct aa_label *tracee, u32 request, + struct common_audit_data *sa) +{ + if (profile_unconfined(tracer)) + return 0; + if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE)) - return xcheck(profile_ptrace_perm(tracer, tracee, request, sa), - profile_ptrace_perm(tracee, tracer, - request << PTRACE_PERM_SHIFT, - sa)); - /* policy uses the old style capability check for ptrace */ - if (profile_unconfined(tracer) || tracer == tracee) + return profile_ptrace_perm(tracer, tracee, request, sa); + + /* profile uses the old style capability check for ptrace */ + if (&tracer->label == tracee) return 0; aad(sa)->label = &tracer->label; - aad(sa)->peer = &tracee->label; + aad(sa)->peer = tracee; aad(sa)->request = 0; aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 1); @@ -115,10 +123,13 @@ static int cross_ptrace_perm(struct aa_profile *tracer, int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee, u32 request) { + struct aa_profile *profile; + u32 xrequest = request << PTRACE_PERM_SHIFT; DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE); - return xcheck_labels_profiles(tracer, tracee, cross_ptrace_perm, - request, &sa); + return xcheck_labels(tracer, tracee, profile, + profile_tracer_perm(profile, tracee, request, &sa), + profile_tracee_perm(profile, tracer, xrequest, &sa)); } -- cgit v1.2.3