From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- security/ipe/ipe.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 security/ipe/ipe.c (limited to 'security/ipe/ipe.c') diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c new file mode 100644 index 000000000..495bb765d --- /dev/null +++ b/security/ipe/ipe.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#include + +#include "ipe.h" +#include "eval.h" +#include "hooks.h" + +extern const char *const ipe_boot_policy; +bool ipe_enabled; + +static struct lsm_blob_sizes ipe_blobs __ro_after_init = { + .lbs_superblock = sizeof(struct ipe_superblock), +#ifdef CONFIG_IPE_PROP_DM_VERITY + .lbs_bdev = sizeof(struct ipe_bdev), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG + .lbs_inode = sizeof(struct ipe_inode), +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ +}; + +static const struct lsm_id ipe_lsmid = { + .name = "ipe", + .id = LSM_ID_IPE, +}; + +struct ipe_superblock *ipe_sb(const struct super_block *sb) +{ + return sb->s_security + ipe_blobs.lbs_superblock; +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b) +{ + return b->bd_security + ipe_blobs.lbs_bdev; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +struct ipe_inode *ipe_inode(const struct inode *inode) +{ + return inode->i_security + ipe_blobs.lbs_inode; +} +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +static struct security_hook_list ipe_hooks[] __ro_after_init = { + LSM_HOOK_INIT(bprm_check_security, ipe_bprm_check_security), + LSM_HOOK_INIT(bprm_creds_for_exec, ipe_bprm_creds_for_exec), + LSM_HOOK_INIT(mmap_file, ipe_mmap_file), + LSM_HOOK_INIT(file_mprotect, ipe_file_mprotect), + LSM_HOOK_INIT(kernel_read_file, ipe_kernel_read_file), + LSM_HOOK_INIT(kernel_load_data, ipe_kernel_load_data), + LSM_HOOK_INIT(initramfs_populated, ipe_unpack_initramfs), +#ifdef CONFIG_IPE_PROP_DM_VERITY + LSM_HOOK_INIT(bdev_free_security, ipe_bdev_free_security), + LSM_HOOK_INIT(bdev_setintegrity, ipe_bdev_setintegrity), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG + LSM_HOOK_INIT(inode_setintegrity, ipe_inode_setintegrity), +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ +}; + +/** + * ipe_init() - Entry point of IPE. + * + * This is called at LSM init, which happens occurs early during kernel + * start up. During this phase, IPE registers its hooks and loads the + * builtin boot policy. + * + * Return: + * * %0 - OK + * * %-ENOMEM - Out of memory (OOM) + */ +static int __init ipe_init(void) +{ + struct ipe_policy *p = NULL; + + security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid); + ipe_enabled = true; + + if (ipe_boot_policy) { + p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy), + NULL, 0); + if (IS_ERR(p)) + return PTR_ERR(p); + + rcu_assign_pointer(ipe_active_policy, p); + } + + return 0; +} + +DEFINE_LSM(ipe) = { + .id = &ipe_lsmid, + .init = ipe_init, + .blobs = &ipe_blobs, + .initcall_fs = ipe_init_securityfs, +}; -- cgit v1.3.1