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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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67678189e4
This patch adds a new ipe_bprm_creds_for_exec() hook that integrates with the AT_EXECVE_CHECK mechanism. To enable script enforcement, interpreters need to incorporate the AT_EXECVE_CHECK flag when calling execveat() on script files before execution. When a userspace interpreter calls execveat() with the AT_EXECVE_CHECK flag, this hook triggers IPE policy evaluation on the script file. The hook only triggers IPE when bprm->is_check is true, ensuring it's being called from an AT_EXECVE_CHECK context. It then builds an evaluation context for an IPE_OP_EXEC operation and invokes IPE policy. The kernel returns the policy decision to the interpreter, which can then decide whether to proceed with script execution. This extends IPE enforcement to indirectly executed scripts, permitting trusted scripts to execute while denying untrusted ones. Signed-off-by: Yanzhu Huang <yanzhuhuang@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@kernel.org>
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved.
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*/
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#include <uapi/linux/lsm.h>
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#include "ipe.h"
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#include "eval.h"
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#include "hooks.h"
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extern const char *const ipe_boot_policy;
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bool ipe_enabled;
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static struct lsm_blob_sizes ipe_blobs __ro_after_init = {
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.lbs_superblock = sizeof(struct ipe_superblock),
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#ifdef CONFIG_IPE_PROP_DM_VERITY
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.lbs_bdev = sizeof(struct ipe_bdev),
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#endif /* CONFIG_IPE_PROP_DM_VERITY */
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#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
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.lbs_inode = sizeof(struct ipe_inode),
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#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */
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};
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static const struct lsm_id ipe_lsmid = {
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.name = "ipe",
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.id = LSM_ID_IPE,
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};
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struct ipe_superblock *ipe_sb(const struct super_block *sb)
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{
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return sb->s_security + ipe_blobs.lbs_superblock;
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}
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#ifdef CONFIG_IPE_PROP_DM_VERITY
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struct ipe_bdev *ipe_bdev(struct block_device *b)
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{
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return b->bd_security + ipe_blobs.lbs_bdev;
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}
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#endif /* CONFIG_IPE_PROP_DM_VERITY */
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#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
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struct ipe_inode *ipe_inode(const struct inode *inode)
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{
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return inode->i_security + ipe_blobs.lbs_inode;
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}
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#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */
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static struct security_hook_list ipe_hooks[] __ro_after_init = {
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LSM_HOOK_INIT(bprm_check_security, ipe_bprm_check_security),
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LSM_HOOK_INIT(bprm_creds_for_exec, ipe_bprm_creds_for_exec),
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LSM_HOOK_INIT(mmap_file, ipe_mmap_file),
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LSM_HOOK_INIT(file_mprotect, ipe_file_mprotect),
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LSM_HOOK_INIT(kernel_read_file, ipe_kernel_read_file),
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LSM_HOOK_INIT(kernel_load_data, ipe_kernel_load_data),
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LSM_HOOK_INIT(initramfs_populated, ipe_unpack_initramfs),
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#ifdef CONFIG_IPE_PROP_DM_VERITY
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LSM_HOOK_INIT(bdev_free_security, ipe_bdev_free_security),
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LSM_HOOK_INIT(bdev_setintegrity, ipe_bdev_setintegrity),
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#endif /* CONFIG_IPE_PROP_DM_VERITY */
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#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
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LSM_HOOK_INIT(inode_setintegrity, ipe_inode_setintegrity),
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#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */
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};
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/**
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* ipe_init() - Entry point of IPE.
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*
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* This is called at LSM init, which happens occurs early during kernel
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* start up. During this phase, IPE registers its hooks and loads the
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* builtin boot policy.
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*
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* Return:
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* * %0 - OK
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* * %-ENOMEM - Out of memory (OOM)
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*/
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static int __init ipe_init(void)
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{
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struct ipe_policy *p = NULL;
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security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid);
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ipe_enabled = true;
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if (ipe_boot_policy) {
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p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy),
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NULL, 0);
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if (IS_ERR(p))
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return PTR_ERR(p);
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rcu_assign_pointer(ipe_active_policy, p);
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}
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return 0;
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}
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DEFINE_LSM(ipe) = {
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.name = "ipe",
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.init = ipe_init,
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.blobs = &ipe_blobs,
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};
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