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d8e47bd066
Increment the incoming FLB refcount in liveupdate_flb_get_incoming() so
that the FLB structure cannot be freed while the caller is actively using
it. Add an additional liveupdate_flb_put_incoming() function so the
caller can explicitly indicate when it is done using the FLB data.
During a Live Update, a subsystem might need to hold onto the incoming
File-Lifecycle-Bound (FLB) data for an extended period, such as during
device enumeration. Incrementing the reference count guarantees that the
data remains valid and accessible until the subsystem releases it,
preventing future use-after-free bugs.
Fixes: cab056f2aa ("liveupdate: luo_flb: introduce File-Lifecycle-Bound global state")
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20260423174032.3140399-3-dmatlack@google.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
144 lines
3.5 KiB
C
144 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2025, Google LLC.
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* Pasha Tatashin <pasha.tatashin@soleen.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME " test: " fmt
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#include <linux/cleanup.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/liveupdate.h>
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#include <linux/module.h>
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#include "../../kernel/liveupdate/luo_internal.h"
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static const struct liveupdate_flb_ops test_flb_ops;
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#define DEFINE_TEST_FLB(i) { \
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.ops = &test_flb_ops, \
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.compatible = LIVEUPDATE_TEST_FLB_COMPATIBLE(i), \
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}
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/* Number of Test FLBs to register with every file handler */
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#define TEST_NFLBS 3
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static struct liveupdate_flb test_flbs[TEST_NFLBS] = {
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DEFINE_TEST_FLB(0),
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DEFINE_TEST_FLB(1),
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DEFINE_TEST_FLB(2),
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};
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#define TEST_FLB_MAGIC_BASE 0xFEEDF00DCAFEBEE0ULL
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static int test_flb_preserve(struct liveupdate_flb_op_args *argp)
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{
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ptrdiff_t index = argp->flb - test_flbs;
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pr_info("%s: preserve was triggered\n", argp->flb->compatible);
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argp->data = TEST_FLB_MAGIC_BASE + index;
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return 0;
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}
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static void test_flb_unpreserve(struct liveupdate_flb_op_args *argp)
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{
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pr_info("%s: unpreserve was triggered\n", argp->flb->compatible);
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}
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static int test_flb_retrieve(struct liveupdate_flb_op_args *argp)
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{
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ptrdiff_t index = argp->flb - test_flbs;
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u64 expected_data = TEST_FLB_MAGIC_BASE + index;
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if (argp->data == expected_data) {
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pr_info("%s: found flb data from the previous boot\n",
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argp->flb->compatible);
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argp->obj = (void *)argp->data;
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} else {
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pr_err("%s: ERROR - incorrect data handle: %llx, expected %llx\n",
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argp->flb->compatible, argp->data, expected_data);
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return -EINVAL;
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}
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return 0;
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}
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static void test_flb_finish(struct liveupdate_flb_op_args *argp)
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{
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ptrdiff_t index = argp->flb - test_flbs;
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void *expected_obj = (void *)(TEST_FLB_MAGIC_BASE + index);
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if (argp->obj == expected_obj) {
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pr_info("%s: finish was triggered\n", argp->flb->compatible);
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} else {
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pr_err("%s: ERROR - finish called with invalid object\n",
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argp->flb->compatible);
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}
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}
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static const struct liveupdate_flb_ops test_flb_ops = {
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.preserve = test_flb_preserve,
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.unpreserve = test_flb_unpreserve,
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.retrieve = test_flb_retrieve,
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.finish = test_flb_finish,
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.owner = THIS_MODULE,
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};
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static void liveupdate_test_init(void)
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{
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static DEFINE_MUTEX(init_lock);
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static bool initialized;
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int i;
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guard(mutex)(&init_lock);
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if (initialized)
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return;
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for (i = 0; i < TEST_NFLBS; i++) {
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struct liveupdate_flb *flb = &test_flbs[i];
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void *obj;
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int err;
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err = liveupdate_flb_get_incoming(flb, &obj);
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if (err && err != -ENODATA && err != -ENOENT) {
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pr_err("liveupdate_flb_get_incoming for %s failed: %pe\n",
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flb->compatible, ERR_PTR(err));
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}
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if (!err)
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liveupdate_flb_put_incoming(flb);
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}
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initialized = true;
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}
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void liveupdate_test_register(struct liveupdate_file_handler *fh)
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{
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int err, i;
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liveupdate_test_init();
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for (i = 0; i < TEST_NFLBS; i++) {
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struct liveupdate_flb *flb = &test_flbs[i];
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err = liveupdate_register_flb(fh, flb);
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if (err) {
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pr_err("Failed to register %s %pe\n",
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flb->compatible, ERR_PTR(err));
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}
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}
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err = liveupdate_register_flb(fh, &test_flbs[0]);
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if (!err || err != -EEXIST) {
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pr_err("Failed: %s should be already registered, but got err: %pe\n",
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test_flbs[0].compatible, ERR_PTR(err));
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}
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pr_info("Registered %d FLBs with file handler: [%s]\n",
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TEST_NFLBS, fh->compatible);
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}
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Pasha Tatashin <pasha.tatashin@soleen.com>");
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MODULE_DESCRIPTION("In-kernel test for LUO mechanism");
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