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 --- fs/ext4/crypto.c | 248 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 248 insertions(+) create mode 100644 fs/ext4/crypto.c (limited to 'fs/ext4/crypto.c') diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c new file mode 100644 index 000000000..9265cfe62 --- /dev/null +++ b/fs/ext4/crypto.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +#include "ext4.h" +#include "xattr.h" +#include "ext4_jbd2.h" + +static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst, + const struct fscrypt_name *src) +{ + memset(dst, 0, sizeof(*dst)); + + dst->usr_fname = src->usr_fname; + dst->disk_name = src->disk_name; + dst->hinfo.hash = src->hash; + dst->hinfo.minor_hash = src->minor_hash; + dst->crypto_buf = src->crypto_buf; +} + +int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname, + int lookup, struct ext4_filename *fname) +{ + struct fscrypt_name name; + int err; + + err = fscrypt_setup_filename(dir, iname, lookup, &name); + if (err) + return err; + + ext4_fname_from_fscrypt_name(fname, &name); + + err = ext4_fname_setup_ci_filename(dir, iname, fname); + if (err) + ext4_fname_free_filename(fname); + + return err; +} + +int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry, + struct ext4_filename *fname) +{ + struct fscrypt_name name; + int err; + + err = fscrypt_prepare_lookup(dir, dentry, &name); + if (err) + return err; + + ext4_fname_from_fscrypt_name(fname, &name); + + err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname); + if (err) + ext4_fname_free_filename(fname); + return err; +} + +void ext4_fname_free_filename(struct ext4_filename *fname) +{ + struct fscrypt_name name; + + name.crypto_buf = fname->crypto_buf; + fscrypt_free_filename(&name); + + fname->crypto_buf.name = NULL; + fname->usr_fname = NULL; + fname->disk_name.name = NULL; + + ext4_fname_free_ci_filename(fname); +} + +static bool uuid_is_zero(__u8 u[16]) +{ + int i; + + for (i = 0; i < 16; i++) + if (u[i]) + return false; + return true; +} + +int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg) +{ + struct super_block *sb = file_inode(filp)->i_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + int err, err2; + handle_t *handle; + + if (!ext4_has_feature_encrypt(sb)) + return -EOPNOTSUPP; + + if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) { + err = mnt_want_write_file(filp); + if (err) + return err; + handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto pwsalt_err_exit; + } + err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh, + EXT4_JTR_NONE); + if (err) + goto pwsalt_err_journal; + lock_buffer(sbi->s_sbh); + generate_random_uuid(sbi->s_es->s_encrypt_pw_salt); + ext4_superblock_csum_set(sb); + unlock_buffer(sbi->s_sbh); + err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh); +pwsalt_err_journal: + err2 = ext4_journal_stop(handle); + if (err2 && !err) + err = err2; +pwsalt_err_exit: + mnt_drop_write_file(filp); + if (err) + return err; + } + + if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16)) + return -EFAULT; + return 0; +} + +static int ext4_get_context(struct inode *inode, void *ctx, size_t len) +{ + return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION, + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len); +} + +static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, + void *fs_data) +{ + handle_t *handle = fs_data; + int res, res2, credits, retries = 0; + + /* + * Encrypting the root directory is not allowed because e2fsck expects + * lost+found to exist and be unencrypted, and encrypting the root + * directory would imply encrypting the lost+found directory as well as + * the filename "lost+found" itself. + */ + if (inode->i_ino == EXT4_ROOT_INO) + return -EPERM; + + if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode))) + return -EINVAL; + + if (ext4_test_inode_flag(inode, EXT4_INODE_DAX)) + return -EOPNOTSUPP; + + res = ext4_convert_inline_data(inode); + if (res) + return res; + + /* + * If a journal handle was specified, then the encryption context is + * being set on a new inode via inheritance and is part of a larger + * transaction to create the inode. Otherwise the encryption context is + * being set on an existing inode in its own transaction. Only in the + * latter case should the "retry on ENOSPC" logic be used. + */ + + if (handle) { + /* + * Since the inode is new it is ok to pass the + * XATTR_CREATE flag. This is necessary to match the + * remaining journal credits check in the set_handle + * function with the credits allocated for the new + * inode. + */ + res = ext4_xattr_set_handle(handle, inode, + EXT4_XATTR_INDEX_ENCRYPTION, + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, + ctx, len, XATTR_CREATE); + if (!res) { + ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); + ext4_clear_inode_state(inode, + EXT4_STATE_MAY_INLINE_DATA); + /* + * Update inode->i_flags - S_ENCRYPTED will be enabled, + * S_DAX may be disabled + */ + ext4_set_inode_flags(inode, false); + } + return res; + } + + res = dquot_initialize(inode); + if (res) + return res; +retry: + res = ext4_xattr_set_credits(inode, len, false /* is_create */, + &credits); + if (res) + return res; + + handle = ext4_journal_start(inode, EXT4_HT_MISC, credits); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION, + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, + ctx, len, 0); + if (!res) { + ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); + /* + * Update inode->i_flags - S_ENCRYPTED will be enabled, + * S_DAX may be disabled + */ + ext4_set_inode_flags(inode, false); + res = ext4_mark_inode_dirty(handle, inode); + if (res) + EXT4_ERROR_INODE(inode, "Failed to mark inode dirty"); + } + res2 = ext4_journal_stop(handle); + + if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; + if (!res) + res = res2; + return res; +} + +static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb) +{ + return EXT4_SB(sb)->s_dummy_enc_policy.policy; +} + +static bool ext4_has_stable_inodes(struct super_block *sb) +{ + return ext4_has_feature_stable_inodes(sb); +} + +const struct fscrypt_operations ext4_cryptops = { + .inode_info_offs = (int)offsetof(struct ext4_inode_info, i_crypt_info) - + (int)offsetof(struct ext4_inode_info, vfs_inode), + .is_block_based = 1, + .has_32bit_inodes = 1, + .supports_subblock_data_units = 1, + .legacy_key_prefix = "ext4:", + .get_context = ext4_get_context, + .set_context = ext4_set_context, + .get_dummy_policy = ext4_get_dummy_policy, + .empty_dir = ext4_empty_dir, + .has_stable_inodes = ext4_has_stable_inodes, +}; -- cgit v1.3.1