From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- fs/readdir.c | 573 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 573 insertions(+) create mode 100644 fs/readdir.c (limited to 'fs/readdir.c') diff --git a/fs/readdir.c b/fs/readdir.c new file mode 100644 index 000000000..76bb1ae3a --- /dev/null +++ b/fs/readdir.c @@ -0,0 +1,573 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/readdir.c + * + * Copyright (C) 1995 Linus Torvalds + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define dirent_size(dirent, len) offsetof(typeof(*(dirent)), d_name[len]) + +/* + * Some filesystems were never converted to '->iterate_shared()' + * and their directory iterators want the inode lock held for + * writing. This wrapper allows for converting from the shared + * semantics to the exclusive inode use. + */ +int wrap_directory_iterator(struct file *file, + struct dir_context *ctx, + int (*iter)(struct file *, struct dir_context *)) +{ + struct inode *inode = file_inode(file); + int ret; + + /* + * We'd love to have an 'inode_upgrade_trylock()' operation, + * see the comment in mmap_upgrade_trylock() in mm/memory.c. + * + * But considering this is for "filesystems that never got + * converted", it really doesn't matter. + * + * Also note that since we have to return with the lock held + * for reading, we can't use the "killable()" locking here, + * since we do need to get the lock even if we're dying. + * + * We could do the write part killably and then get the read + * lock unconditionally if it mattered, but see above on why + * this does the very simplistic conversion. + */ + up_read(&inode->i_rwsem); + down_write(&inode->i_rwsem); + + /* + * Since we dropped the inode lock, we should do the + * DEADDIR test again. See 'iterate_dir()' below. + * + * Note that we don't need to re-do the f_pos games, + * since the file must be locked wrt f_pos anyway. + */ + ret = -ENOENT; + if (!IS_DEADDIR(inode)) + ret = iter(file, ctx); + + downgrade_write(&inode->i_rwsem); + return ret; +} +EXPORT_SYMBOL(wrap_directory_iterator); + +/* + * Note the "unsafe_put_user()" semantics: we goto a + * label for errors. + */ +#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \ + char __user *dst = (_dst); \ + const char *src = (_src); \ + size_t len = (_len); \ + unsafe_put_user(0, dst+len, label); \ + unsafe_copy_to_user(dst, src, len, label); \ +} while (0) + + +int iterate_dir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + int res = -ENOTDIR; + + if (!file->f_op->iterate_shared) + goto out; + + res = security_file_permission(file, MAY_READ); + if (res) + goto out; + + res = fsnotify_file_perm(file, MAY_READ); + if (res) + goto out; + + res = down_read_killable(&inode->i_rwsem); + if (res) + goto out; + + res = -ENOENT; + if (!IS_DEADDIR(inode)) { + ctx->pos = file->f_pos; + res = file->f_op->iterate_shared(file, ctx); + file->f_pos = ctx->pos; + fsnotify_access(file); + file_accessed(file); + } + inode_unlock_shared(inode); +out: + return res; +} +EXPORT_SYMBOL(iterate_dir); + +/* + * POSIX says that a dirent name cannot contain NULL or a '/'. + * + * It's not 100% clear what we should really do in this case. + * The filesystem is clearly corrupted, but returning a hard + * error means that you now don't see any of the other names + * either, so that isn't a perfect alternative. + * + * And if you return an error, what error do you use? Several + * filesystems seem to have decided on EUCLEAN being the error + * code for EFSCORRUPTED, and that may be the error to use. Or + * just EIO, which is perhaps more obvious to users. + * + * In order to see the other file names in the directory, the + * caller might want to make this a "soft" error: skip the + * entry, and return the error at the end instead. + * + * Note that this should likely do a "memchr(name, 0, len)" + * check too, since that would be filesystem corruption as + * well. However, that case can't actually confuse user space, + * which has to do a strlen() on the name anyway to find the + * filename length, and the above "soft error" worry means + * that it's probably better left alone until we have that + * issue clarified. + * + * Note the PATH_MAX check - it's arbitrary but the real + * kernel limit on a possible path component, not NAME_MAX, + * which is the technical standard limit. + */ +static int verify_dirent_name(const char *name, int len) +{ + if (len <= 0 || len >= PATH_MAX) + return -EIO; + if (memchr(name, '/', len)) + return -EIO; + return 0; +} + +/* + * Traditional linux readdir() handling.. + * + * "count=1" is a special case, meaning that the buffer is one + * dirent-structure in size and that the code can't handle more + * anyway. Thus the special "fillonedir()" function for that + * case (the low-level handlers don't need to care about this). + */ + +#ifdef __ARCH_WANT_OLD_READDIR + +struct old_linux_dirent { + unsigned long d_ino; + unsigned long d_offset; + unsigned short d_namlen; + char d_name[]; +}; + +struct readdir_callback { + struct dir_context ctx; + struct old_linux_dirent __user * dirent; + int result; +}; + +static bool fillonedir(struct dir_context *ctx, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct readdir_callback *buf = + container_of(ctx, struct readdir_callback, ctx); + struct old_linux_dirent __user * dirent; + unsigned long d_ino; + + if (buf->result) + return false; + buf->result = verify_dirent_name(name, namlen); + if (buf->result) + return false; + d_ino = ino; + if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { + buf->result = -EOVERFLOW; + return false; + } + buf->result++; + dirent = buf->dirent; + scoped_user_write_access_size(dirent, dirent_size(dirent, namlen + 1), efault) { + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(offset, &dirent->d_offset, efault); + unsafe_put_user(namlen, &dirent->d_namlen, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } + return true; +efault: + buf->result = -EFAULT; + return false; +} + +SYSCALL_DEFINE3(old_readdir, unsigned int, fd, + struct old_linux_dirent __user *, dirent, unsigned int, count) +{ + int error; + CLASS(fd_pos, f)(fd); + struct readdir_callback buf = { + .ctx.actor = fillonedir, + .ctx.count = 1, /* Hint to fs: just one entry. */ + .dirent = dirent + }; + + if (fd_empty(f)) + return -EBADF; + + error = iterate_dir(fd_file(f), &buf.ctx); + if (buf.result) + error = buf.result; + + return error; +} + +#endif /* __ARCH_WANT_OLD_READDIR */ + +/* + * New, all-improved, singing, dancing, iBCS2-compliant getdents() + * interface. + */ +struct linux_dirent { + unsigned long d_ino; + unsigned long d_off; + unsigned short d_reclen; + char d_name[]; +}; + +struct getdents_callback { + struct dir_context ctx; + struct linux_dirent __user * current_dir; + int prev_reclen; + int error; +}; + +static bool filldir(struct dir_context *ctx, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct linux_dirent __user *dirent, *prev; + struct getdents_callback *buf = + container_of(ctx, struct getdents_callback, ctx); + unsigned long d_ino; + int reclen = ALIGN(dirent_size(dirent, namlen + 2), sizeof(long)); + int prev_reclen; + unsigned int flags = d_type; + + BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK); + d_type &= S_DT_MASK; + + buf->error = verify_dirent_name(name, namlen); + if (unlikely(buf->error)) + return false; + buf->error = -EINVAL; /* only used if we fail.. */ + if (reclen > ctx->count) + return false; + d_ino = ino; + if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { + buf->error = -EOVERFLOW; + return false; + } + prev_reclen = buf->prev_reclen; + if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current)) + return false; + dirent = buf->current_dir; + prev = (void __user *) dirent - prev_reclen; + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + /* This might be 'dirent->d_off', but if so it will get overwritten */ + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, (char __user *)dirent + reclen - 1, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } + + buf->current_dir = (void __user *)dirent + reclen; + buf->prev_reclen = reclen; + ctx->count -= reclen; + return true; +efault: + buf->error = -EFAULT; + return false; +} + +SYSCALL_DEFINE3(getdents, unsigned int, fd, + struct linux_dirent __user *, dirent, unsigned int, count) +{ + CLASS(fd_pos, f)(fd); + struct getdents_callback buf = { + .ctx.actor = filldir, + .ctx.count = count, + .ctx.dt_flags_mask = FILLDIR_FLAG_NOINTR, + .current_dir = dirent + }; + int error; + + if (fd_empty(f)) + return -EBADF; + + error = iterate_dir(fd_file(f), &buf.ctx); + if (error >= 0) + error = buf.error; + if (buf.prev_reclen) { + struct linux_dirent __user * lastdirent; + lastdirent = (void __user *)buf.current_dir - buf.prev_reclen; + + if (put_user(buf.ctx.pos, &lastdirent->d_off)) + error = -EFAULT; + else + error = count - buf.ctx.count; + } + return error; +} + +struct getdents_callback64 { + struct dir_context ctx; + struct linux_dirent64 __user * current_dir; + int prev_reclen; + int error; +}; + +static bool filldir64(struct dir_context *ctx, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct linux_dirent64 __user *dirent, *prev; + struct getdents_callback64 *buf = + container_of(ctx, struct getdents_callback64, ctx); + int reclen = ALIGN(dirent_size(dirent, namlen + 1), sizeof(u64)); + int prev_reclen; + unsigned int flags = d_type; + + BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK); + d_type &= S_DT_MASK; + + buf->error = verify_dirent_name(name, namlen); + if (unlikely(buf->error)) + return false; + buf->error = -EINVAL; /* only used if we fail.. */ + if (reclen > ctx->count) + return false; + prev_reclen = buf->prev_reclen; + if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current)) + return false; + dirent = buf->current_dir; + prev = (void __user *)dirent - prev_reclen; + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + /* This might be 'dirent->d_off', but if so it will get overwritten */ + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, &dirent->d_type, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } + + buf->prev_reclen = reclen; + buf->current_dir = (void __user *)dirent + reclen; + ctx->count -= reclen; + return true; + +efault: + buf->error = -EFAULT; + return false; +} + +SYSCALL_DEFINE3(getdents64, unsigned int, fd, + struct linux_dirent64 __user *, dirent, unsigned int, count) +{ + CLASS(fd_pos, f)(fd); + struct getdents_callback64 buf = { + .ctx.actor = filldir64, + .ctx.count = count, + .ctx.dt_flags_mask = FILLDIR_FLAG_NOINTR, + .current_dir = dirent + }; + int error; + + if (fd_empty(f)) + return -EBADF; + + error = iterate_dir(fd_file(f), &buf.ctx); + if (error >= 0) + error = buf.error; + if (buf.prev_reclen) { + struct linux_dirent64 __user * lastdirent; + typeof(lastdirent->d_off) d_off = buf.ctx.pos; + + lastdirent = (void __user *) buf.current_dir - buf.prev_reclen; + if (put_user(d_off, &lastdirent->d_off)) + error = -EFAULT; + else + error = count - buf.ctx.count; + } + return error; +} + +#ifdef CONFIG_COMPAT +struct compat_old_linux_dirent { + compat_ulong_t d_ino; + compat_ulong_t d_offset; + unsigned short d_namlen; + char d_name[]; +}; + +struct compat_readdir_callback { + struct dir_context ctx; + struct compat_old_linux_dirent __user *dirent; + int result; +}; + +static bool compat_fillonedir(struct dir_context *ctx, const char *name, + int namlen, loff_t offset, u64 ino, + unsigned int d_type) +{ + struct compat_readdir_callback *buf = + container_of(ctx, struct compat_readdir_callback, ctx); + struct compat_old_linux_dirent __user *dirent; + compat_ulong_t d_ino; + + if (buf->result) + return false; + buf->result = verify_dirent_name(name, namlen); + if (buf->result) + return false; + d_ino = ino; + if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { + buf->result = -EOVERFLOW; + return false; + } + buf->result++; + dirent = buf->dirent; + scoped_user_write_access_size(dirent, dirent_size(dirent, namlen + 1), efault) { + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(offset, &dirent->d_offset, efault); + unsafe_put_user(namlen, &dirent->d_namlen, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } + return true; +efault: + buf->result = -EFAULT; + return false; +} + +COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd, + struct compat_old_linux_dirent __user *, dirent, unsigned int, count) +{ + int error; + CLASS(fd_pos, f)(fd); + struct compat_readdir_callback buf = { + .ctx.actor = compat_fillonedir, + .ctx.count = 1, /* Hint to fs: just one entry. */ + .dirent = dirent + }; + + if (fd_empty(f)) + return -EBADF; + + error = iterate_dir(fd_file(f), &buf.ctx); + if (buf.result) + error = buf.result; + + return error; +} + +struct compat_linux_dirent { + compat_ulong_t d_ino; + compat_ulong_t d_off; + unsigned short d_reclen; + char d_name[]; +}; + +struct compat_getdents_callback { + struct dir_context ctx; + struct compat_linux_dirent __user *current_dir; + int prev_reclen; + int error; +}; + +static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct compat_linux_dirent __user *dirent, *prev; + struct compat_getdents_callback *buf = + container_of(ctx, struct compat_getdents_callback, ctx); + compat_ulong_t d_ino; + int reclen = ALIGN(dirent_size(dirent, namlen + 2), sizeof(compat_long_t)); + int prev_reclen; + unsigned int flags = d_type; + + BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK); + d_type &= S_DT_MASK; + + buf->error = verify_dirent_name(name, namlen); + if (unlikely(buf->error)) + return false; + buf->error = -EINVAL; /* only used if we fail.. */ + if (reclen > ctx->count) + return false; + d_ino = ino; + if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { + buf->error = -EOVERFLOW; + return false; + } + prev_reclen = buf->prev_reclen; + if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current)) + return false; + dirent = buf->current_dir; + prev = (void __user *) dirent - prev_reclen; + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, (char __user *)dirent + reclen - 1, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } + + buf->prev_reclen = reclen; + buf->current_dir = (void __user *)dirent + reclen; + ctx->count -= reclen; + return true; +efault: + buf->error = -EFAULT; + return false; +} + +COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd, + struct compat_linux_dirent __user *, dirent, unsigned int, count) +{ + CLASS(fd_pos, f)(fd); + struct compat_getdents_callback buf = { + .ctx.actor = compat_filldir, + .ctx.count = count, + .ctx.dt_flags_mask = FILLDIR_FLAG_NOINTR, + .current_dir = dirent, + }; + int error; + + if (fd_empty(f)) + return -EBADF; + + error = iterate_dir(fd_file(f), &buf.ctx); + if (error >= 0) + error = buf.error; + if (buf.prev_reclen) { + struct compat_linux_dirent __user * lastdirent; + lastdirent = (void __user *)buf.current_dir - buf.prev_reclen; + + if (put_user(buf.ctx.pos, &lastdirent->d_off)) + error = -EFAULT; + else + error = count - buf.ctx.count; + } + return error; +} +#endif -- cgit v1.3.1