From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- fs/hfsplus/dir.c | 643 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 643 insertions(+) create mode 100644 fs/hfsplus/dir.c (limited to 'fs/hfsplus/dir.c') diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c new file mode 100644 index 000000000..51fcba2e6 --- /dev/null +++ b/fs/hfsplus/dir.c @@ -0,0 +1,643 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/hfsplus/dir.c + * + * Copyright (C) 2001 + * Brad Boyer (flar@allandria.com) + * (C) 2003 Ardis Technologies + * + * Handling of directories + */ + +#include +#include +#include +#include +#include + +#include "hfsplus_fs.h" +#include "hfsplus_raw.h" +#include "xattr.h" + +static inline void hfsplus_instantiate(struct dentry *dentry, + struct inode *inode, u32 cnid) +{ + dentry->d_fsdata = (void *)(unsigned long)cnid; + d_instantiate(dentry, inode); +} + +/* Find the entry inside dir named dentry->d_name */ +static struct dentry *hfsplus_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + struct inode *inode = NULL; + struct hfs_find_data fd; + struct super_block *sb; + hfsplus_cat_entry entry; + int err; + u32 cnid, linkid = 0; + u16 type; + + sb = dir->i_sb; + + dentry->d_fsdata = NULL; + err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd); + if (err) + return ERR_PTR(err); + err = hfsplus_cat_build_key(sb, fd.search_key, dir->i_ino, + &dentry->d_name); + if (unlikely(err < 0)) + goto fail; +again: + err = hfsplus_brec_read_cat(&fd, &entry); + if (err) { + if (err == -ENOENT) { + hfs_find_exit(&fd); + /* No such entry */ + inode = NULL; + goto out; + } + goto fail; + } + type = be16_to_cpu(entry.type); + if (type == HFSPLUS_FOLDER) { + if (fd.entrylength < sizeof(struct hfsplus_cat_folder)) { + err = -EIO; + goto fail; + } + cnid = be32_to_cpu(entry.folder.id); + dentry->d_fsdata = (void *)(unsigned long)cnid; + } else if (type == HFSPLUS_FILE) { + if (fd.entrylength < sizeof(struct hfsplus_cat_file)) { + err = -EIO; + goto fail; + } + cnid = be32_to_cpu(entry.file.id); + if (entry.file.user_info.fdType == + cpu_to_be32(HFSP_HARDLINK_TYPE) && + entry.file.user_info.fdCreator == + cpu_to_be32(HFSP_HFSPLUS_CREATOR) && + HFSPLUS_SB(sb)->hidden_dir && + (entry.file.create_date == + HFSPLUS_I(HFSPLUS_SB(sb)->hidden_dir)-> + create_date || + entry.file.create_date == + HFSPLUS_I(d_inode(sb->s_root))-> + create_date)) { + struct qstr str; + char name[32]; + + if (dentry->d_fsdata) { + /* + * We found a link pointing to another link, + * so ignore it and treat it as regular file. + */ + cnid = (unsigned long)dentry->d_fsdata; + linkid = 0; + } else { + dentry->d_fsdata = (void *)(unsigned long)cnid; + linkid = + be32_to_cpu(entry.file.permissions.dev); + str.len = sprintf(name, "iNode%d", linkid); + str.name = name; + err = hfsplus_cat_build_key(sb, fd.search_key, + HFSPLUS_SB(sb)->hidden_dir->i_ino, + &str); + if (unlikely(err < 0)) + goto fail; + goto again; + } + } else if (!dentry->d_fsdata) + dentry->d_fsdata = (void *)(unsigned long)cnid; + } else { + pr_err("invalid catalog entry type in lookup\n"); + err = -EIO; + goto fail; + } + hfs_find_exit(&fd); + inode = hfsplus_iget(dir->i_sb, cnid); + if (IS_ERR(inode)) + return ERR_CAST(inode); + if (S_ISREG(inode->i_mode)) + HFSPLUS_I(inode)->linkid = linkid; +out: + return d_splice_alias(inode, dentry); +fail: + hfs_find_exit(&fd); + return ERR_PTR(err); +} + +static int hfsplus_readdir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + int len, err; + char *strbuf; + hfsplus_cat_entry entry; + struct hfs_find_data fd; + struct hfsplus_readdir_data *rd; + u16 type; + + if (file->f_pos >= inode->i_size) + return 0; + + err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd); + if (err) + return err; + strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN + 1, GFP_KERNEL); + if (!strbuf) { + err = -ENOMEM; + goto out; + } + hfsplus_cat_build_key_with_cnid(sb, fd.search_key, inode->i_ino); + err = hfs_brec_find(&fd, hfs_find_rec_by_key); + if (err) + goto out; + + if (ctx->pos == 0) { + /* This is completely artificial... */ + if (!dir_emit_dot(file, ctx)) + goto out; + ctx->pos = 1; + } + if (ctx->pos == 1) { + if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) { + err = -EIO; + goto out; + } + + hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, + fd.entrylength); + if (be16_to_cpu(entry.type) != HFSPLUS_FOLDER_THREAD) { + pr_err("bad catalog folder thread\n"); + err = -EIO; + goto out; + } + if (fd.entrylength < HFSPLUS_MIN_THREAD_SZ) { + pr_err("truncated catalog thread\n"); + err = -EIO; + goto out; + } + if (!dir_emit(ctx, "..", 2, + be32_to_cpu(entry.thread.parentID), DT_DIR)) + goto out; + ctx->pos = 2; + } + if (ctx->pos >= inode->i_size) + goto out; + rd = file->private_data; + if (rd && rd->pos == ctx->pos) { + memcpy(fd.search_key, &rd->key, sizeof(struct hfsplus_cat_key)); + err = hfs_brec_find(&fd, hfs_find_rec_by_key); + if (err == -ENOENT) + err = hfs_brec_goto(&fd, 1); + } else { + err = hfs_brec_goto(&fd, ctx->pos - 1); + } + if (err) + goto out; + for (;;) { + if (be32_to_cpu(fd.key->cat.parent) != inode->i_ino) { + pr_err("walked past end of dir\n"); + err = -EIO; + goto out; + } + + if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) { + err = -EIO; + goto out; + } + + hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, + fd.entrylength); + type = be16_to_cpu(entry.type); + len = NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN; + err = hfsplus_uni2asc_str(sb, &fd.key->cat.name, strbuf, &len); + if (err) + goto out; + if (type == HFSPLUS_FOLDER) { + if (fd.entrylength < + sizeof(struct hfsplus_cat_folder)) { + pr_err("small dir entry\n"); + err = -EIO; + goto out; + } + if (HFSPLUS_SB(sb)->hidden_dir && + HFSPLUS_SB(sb)->hidden_dir->i_ino == + be32_to_cpu(entry.folder.id)) + goto next; + if (!dir_emit(ctx, strbuf, len, + be32_to_cpu(entry.folder.id), DT_DIR)) + break; + } else if (type == HFSPLUS_FILE) { + u16 mode; + unsigned type = DT_UNKNOWN; + + if (fd.entrylength < sizeof(struct hfsplus_cat_file)) { + pr_err("small file entry\n"); + err = -EIO; + goto out; + } + + mode = be16_to_cpu(entry.file.permissions.mode); + if (S_ISREG(mode)) + type = DT_REG; + else if (S_ISLNK(mode)) + type = DT_LNK; + else if (S_ISFIFO(mode)) + type = DT_FIFO; + else if (S_ISCHR(mode)) + type = DT_CHR; + else if (S_ISBLK(mode)) + type = DT_BLK; + else if (S_ISSOCK(mode)) + type = DT_SOCK; + + if (!dir_emit(ctx, strbuf, len, + be32_to_cpu(entry.file.id), type)) + break; + } else { + pr_err("bad catalog entry type\n"); + err = -EIO; + goto out; + } +next: + ctx->pos++; + if (ctx->pos >= inode->i_size) + goto out; + err = hfs_brec_goto(&fd, 1); + if (err) + goto out; + } + if (!rd) { + rd = kmalloc_obj(struct hfsplus_readdir_data); + if (!rd) { + err = -ENOMEM; + goto out; + } + file->private_data = rd; + } + rd->pos = ctx->pos; + memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key)); +out: + kfree(strbuf); + hfs_find_exit(&fd); + return err; +} + +static int hfsplus_dir_release(struct inode *inode, struct file *file) +{ + kfree(file->private_data); + return 0; +} + +static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir, + struct dentry *dst_dentry) +{ + struct hfsplus_sb_info *sbi = HFSPLUS_SB(dst_dir->i_sb); + struct inode *inode = d_inode(src_dentry); + struct inode *src_dir = d_inode(src_dentry->d_parent); + struct qstr str; + char name[32]; + u32 cnid, id; + int res; + + if (HFSPLUS_IS_RSRC(inode)) + return -EPERM; + if (!S_ISREG(inode->i_mode)) + return -EPERM; + + hfs_dbg("src_dir->i_ino %llu, dst_dir->i_ino %llu, inode->i_ino %llu\n", + src_dir->i_ino, dst_dir->i_ino, inode->i_ino); + + mutex_lock(&sbi->vh_mutex); + if (inode->i_ino == (u32)(unsigned long)src_dentry->d_fsdata) { + for (;;) { + get_random_bytes(&id, sizeof(cnid)); + id &= 0x3fffffff; + str.name = name; + str.len = sprintf(name, "iNode%d", id); + res = hfsplus_rename_cat(inode->i_ino, + src_dir, &src_dentry->d_name, + sbi->hidden_dir, &str); + if (!res) + break; + if (res != -EEXIST) + goto out; + } + HFSPLUS_I(inode)->linkid = id; + cnid = sbi->next_cnid++; + src_dentry->d_fsdata = (void *)(unsigned long)cnid; + res = hfsplus_create_cat(cnid, src_dir, + &src_dentry->d_name, inode); + if (res) + /* panic? */ + goto out; + sbi->file_count++; + } + cnid = sbi->next_cnid++; + res = hfsplus_create_cat(cnid, dst_dir, &dst_dentry->d_name, inode); + if (res) + goto out; + + inc_nlink(inode); + hfsplus_instantiate(dst_dentry, inode, cnid); + ihold(inode); + inode_set_ctime_current(inode); + mark_inode_dirty(inode); + sbi->file_count++; + hfsplus_mark_mdb_dirty(dst_dir->i_sb); + + res = hfsplus_cat_write_inode(src_dir); + if (res) + goto out; + + res = hfsplus_cat_write_inode(dst_dir); + if (res) + goto out; + + res = hfsplus_cat_write_inode(sbi->hidden_dir); + if (res) + goto out; + + res = hfsplus_cat_write_inode(inode); + +out: + mutex_unlock(&sbi->vh_mutex); + return res; +} + +static int hfsplus_unlink(struct inode *dir, struct dentry *dentry) +{ + struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb); + struct inode *inode = d_inode(dentry); + struct qstr str; + char name[32]; + u32 cnid; + int res; + + if (HFSPLUS_IS_RSRC(inode)) + return -EPERM; + + hfs_dbg("dir->i_ino %llu, inode->i_ino %llu\n", + dir->i_ino, inode->i_ino); + + mutex_lock(&sbi->vh_mutex); + cnid = (u32)(unsigned long)dentry->d_fsdata; + if (inode->i_ino == cnid && + atomic_read(&HFSPLUS_I(inode)->opencnt)) { + str.name = name; + str.len = sprintf(name, "temp%llu", inode->i_ino); + res = hfsplus_rename_cat(inode->i_ino, + dir, &dentry->d_name, + sbi->hidden_dir, &str); + if (!res) { + inode->i_flags |= S_DEAD; + drop_nlink(inode); + } + goto out; + } + res = hfsplus_delete_cat(cnid, dir, &dentry->d_name); + if (res) + goto out; + + if (inode->i_nlink > 0) + drop_nlink(inode); + if (inode->i_ino == cnid) + clear_nlink(inode); + if (!inode->i_nlink) { + if (inode->i_ino != cnid) { + sbi->file_count--; + if (!atomic_read(&HFSPLUS_I(inode)->opencnt)) { + res = hfsplus_delete_cat(inode->i_ino, + sbi->hidden_dir, + NULL); + if (!res) + hfsplus_delete_inode(inode); + } else + inode->i_flags |= S_DEAD; + } else + hfsplus_delete_inode(inode); + } else + sbi->file_count--; + inode_set_ctime_current(inode); + mark_inode_dirty(inode); +out: + if (!res) { + res = hfsplus_cat_write_inode(dir); + if (!res) { + res = hfsplus_cat_write_inode(sbi->hidden_dir); + if (!res) + res = hfsplus_cat_write_inode(inode); + } + } + + mutex_unlock(&sbi->vh_mutex); + return res; +} + +static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb); + struct inode *inode = d_inode(dentry); + int res; + + if (inode->i_size != 2) + return -ENOTEMPTY; + + mutex_lock(&sbi->vh_mutex); + res = hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name); + if (res) + goto out; + clear_nlink(inode); + inode_set_ctime_current(inode); + hfsplus_delete_inode(inode); + mark_inode_dirty(inode); + + res = hfsplus_cat_write_inode(dir); +out: + mutex_unlock(&sbi->vh_mutex); + return res; +} + +static int hfsplus_symlink(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, const char *symname) +{ + struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb); + struct inode *inode; + int res = -ENOMEM; + + mutex_lock(&sbi->vh_mutex); + inode = hfsplus_new_inode(dir->i_sb, dir, S_IFLNK | S_IRWXUGO); + if (!inode) + goto out; + + hfs_dbg("dir->i_ino %llu, inode->i_ino %llu\n", + dir->i_ino, inode->i_ino); + + res = page_symlink(inode, symname, strlen(symname) + 1); + if (res) + goto out_err; + + res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode); + if (res) + goto out_err; + + res = hfsplus_init_security(inode, dir, &dentry->d_name); + if (res == -EOPNOTSUPP) + res = 0; /* Operation is not supported. */ + else if (res) { + /* Try to delete anyway without error analysis. */ + hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name); + goto out_err; + } + + hfsplus_instantiate(dentry, inode, inode->i_ino); + mark_inode_dirty(inode); + + res = hfsplus_cat_write_inode(dir); + if (res) + goto out; + + res = hfsplus_cat_write_inode(inode); + goto out; + +out_err: + clear_nlink(inode); + hfsplus_delete_inode(inode); + iput(inode); +out: + mutex_unlock(&sbi->vh_mutex); + return res; +} + +static int hfsplus_mknod(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t rdev) +{ + struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb); + struct inode *inode; + int res = -ENOMEM; + + mutex_lock(&sbi->vh_mutex); + inode = hfsplus_new_inode(dir->i_sb, dir, mode); + if (!inode) + goto out; + + hfs_dbg("dir->i_ino %llu, inode->i_ino %llu\n", + dir->i_ino, inode->i_ino); + + if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) + init_special_inode(inode, mode, rdev); + + res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode); + if (res) + goto failed_mknod; + + res = hfsplus_init_security(inode, dir, &dentry->d_name); + if (res == -EOPNOTSUPP) + res = 0; /* Operation is not supported. */ + else if (res) { + /* Try to delete anyway without error analysis. */ + hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name); + goto failed_mknod; + } + + hfsplus_instantiate(dentry, inode, inode->i_ino); + mark_inode_dirty(inode); + + res = hfsplus_cat_write_inode(dir); + if (res) + goto out; + + res = hfsplus_cat_write_inode(inode); + goto out; + +failed_mknod: + clear_nlink(inode); + hfsplus_delete_inode(inode); + iput(inode); +out: + mutex_unlock(&sbi->vh_mutex); + return res; +} + +static int hfsplus_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + return hfsplus_mknod(&nop_mnt_idmap, dir, dentry, mode, 0); +} + +static struct dentry *hfsplus_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + return ERR_PTR(hfsplus_mknod(&nop_mnt_idmap, dir, dentry, mode, 0)); +} + +static int hfsplus_rename(struct mnt_idmap *idmap, + struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags) +{ + int res; + + if (flags & ~RENAME_NOREPLACE) + return -EINVAL; + + /* Unlink destination if it already exists */ + if (d_really_is_positive(new_dentry)) { + if (d_is_dir(new_dentry)) + res = hfsplus_rmdir(new_dir, new_dentry); + else + res = hfsplus_unlink(new_dir, new_dentry); + if (res) + return res; + } + + res = hfsplus_rename_cat((u32)(unsigned long)old_dentry->d_fsdata, + old_dir, &old_dentry->d_name, + new_dir, &new_dentry->d_name); + if (!res) { + struct inode *inode = d_inode(old_dentry); + + new_dentry->d_fsdata = old_dentry->d_fsdata; + + inode_set_ctime_current(inode); + mark_inode_dirty(inode); + + res = hfsplus_cat_write_inode(old_dir); + if (res) + return res; + + res = hfsplus_cat_write_inode(new_dir); + if (res) + return res; + + res = hfsplus_cat_write_inode(inode); + } + return res; +} + +const struct inode_operations hfsplus_dir_inode_operations = { + .lookup = hfsplus_lookup, + .create = hfsplus_create, + .link = hfsplus_link, + .unlink = hfsplus_unlink, + .mkdir = hfsplus_mkdir, + .rmdir = hfsplus_rmdir, + .symlink = hfsplus_symlink, + .mknod = hfsplus_mknod, + .rename = hfsplus_rename, + .getattr = hfsplus_getattr, + .listxattr = hfsplus_listxattr, + .fileattr_get = hfsplus_fileattr_get, + .fileattr_set = hfsplus_fileattr_set, +}; + +const struct file_operations hfsplus_dir_operations = { + .fsync = hfsplus_file_fsync, + .read = generic_read_dir, + .iterate_shared = hfsplus_readdir, + .unlocked_ioctl = hfsplus_ioctl, + .llseek = generic_file_llseek, + .release = hfsplus_dir_release, +}; -- cgit v1.3.1