apparmor: allow ptrace checks to be finer grained than just capability (290f458a) · Commits · e / devices / android_kernel_oneplus_sm7250

security/apparmor/apparmorfs.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -2086,6 +2086,11 @@ static struct aa_sfs_entry aa_sfs_entry_file[] = {
		{ }
		};

		static struct aa_sfs_entry aa_sfs_entry_ptrace[] = {
		AA_SFS_FILE_STRING("mask", "read trace"),
		{ }
		};

		static struct aa_sfs_entry aa_sfs_entry_domain[] = {
		AA_SFS_FILE_BOOLEAN("change_hat", 1),
		AA_SFS_FILE_BOOLEAN("change_hatv", 1),
		@@ -2125,6 +2130,7 @@ static struct aa_sfs_entry aa_sfs_entry_features[] = {
		AA_SFS_FILE_U64("capability", VFS_CAP_FLAGS_MASK),
		AA_SFS_DIR("rlimit", aa_sfs_entry_rlimit),
		AA_SFS_DIR("caps", aa_sfs_entry_caps),
		AA_SFS_DIR("ptrace", aa_sfs_entry_ptrace),
		AA_SFS_DIR("query", aa_sfs_entry_query),
		{ }
		};

security/apparmor/include/ipc.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,12 @@ struct aa_profile;

		#define AA_PTRACE_TRACE MAY_WRITE
		#define AA_PTRACE_READ MAY_READ
		#define AA_MAY_BE_TRACED AA_MAY_APPEND
		#define AA_MAY_BE_READ AA_MAY_CREATE
		#define PTRACE_PERM_SHIFT 2

		#define AA_PTRACE_PERM_MASK (AA_PTRACE_READ \| AA_PTRACE_TRACE \| \
		AA_MAY_BE_READ \| AA_MAY_BE_TRACED)

		int aa_may_ptrace(struct aa_label tracer, struct aa_label tracee,
		u32 request);

security/apparmor/ipc.c

+56 −0

Original line number	Diff line number	Diff line
		@@ -21,20 +21,76 @@
		#include "include/policy.h"
		#include "include/ipc.h"

		/**
		* audit_ptrace_mask - convert mask to permission string
		* @buffer: buffer to write string to (NOT NULL)
		* @mask: permission mask to convert
		*/
		static void audit_ptrace_mask(struct audit_buffer *ab, u32 mask)
		{
		switch (mask) {
		case MAY_READ:
		audit_log_string(ab, "read");
		break;
		case MAY_WRITE:
		audit_log_string(ab, "trace");
		break;
		case AA_MAY_BE_READ:
		audit_log_string(ab, "readby");
		break;
		case AA_MAY_BE_TRACED:
		audit_log_string(ab, "tracedby");
		break;
		}
		}

		/* call back to audit ptrace fields */
		static void audit_ptrace_cb(struct audit_buffer ab, void va)
		{
		struct common_audit_data *sa = va;

		if (aad(sa)->request & AA_PTRACE_PERM_MASK) {
		audit_log_format(ab, " requested_mask=");
		audit_ptrace_mask(ab, aad(sa)->request);

		if (aad(sa)->denied & AA_PTRACE_PERM_MASK) {
		audit_log_format(ab, " denied_mask=");
		audit_ptrace_mask(ab, aad(sa)->denied);
		}
		}
		audit_log_format(ab, " peer=");
		aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
		FLAGS_NONE, GFP_ATOMIC);
		}

		/* TODO: conditionals */
		static int profile_ptrace_perm(struct aa_profile *profile,
		struct aa_profile *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,
		&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)
		{
		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 0;