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charset="UTF-8" Currently, if a remote fails to register, its resources will leak and will not be properly torn down. To prevent a user accessing a remote tracefs that is about to be destroyed, keep track of the registered remotes in a global list, similarly to trace instances. Gate the tracefs open function based on the presence of the remote in that list. Signed-off-by: Vincent Donnefort --- kernel/trace/trace_remote.c | 100 +++++++++++++++++++++++++++++++----- 1 file changed, 87 insertions(+), 13 deletions(-) diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 2d5bc423efca..e8cbbd01964d 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -39,6 +39,7 @@ struct trace_remote_iterator { }; struct trace_remote { + struct list_head node; struct trace_remote_callbacks *cbs; void *priv; struct trace_buffer *trace_buffer; @@ -57,6 +58,9 @@ struct trace_remote { bool tracing_on; }; +static DEFINE_MUTEX(trace_remotes_lock); +static LIST_HEAD(trace_remotes); + static bool trace_remote_loaded(struct trace_remote *remote) { return !!remote->trace_buffer; @@ -170,6 +174,60 @@ static void trace_remote_reset(struct trace_remote *remote, int cpu) trace_remote_try_unload(remote); } +static int trace_remote_tracefs_open(struct inode *inode, struct file *filp) +{ + void *i_private = inode->i_private; + struct trace_remote *r; + + if (!i_private) + return -ENODEV; + + guard(mutex)(&trace_remotes_lock); + + /* i_private is either a struct trace_remote or a struct remote_event */ + list_for_each_entry(r, &trace_remotes, node) { + if (r == i_private) + return 0; + if (!r->events) + continue; + if (i_private >= (void *)r->events && + i_private < (void *)(r->events + r->nr_events)) + return 0; + } + + return -ENODEV; +} + +#define DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static int __name ## _open(struct inode *inode, struct file *file) \ +{ \ + int ret = trace_remote_tracefs_open(inode, file); \ + \ + if (ret) \ + return ret; \ + \ + return single_open(file, __name ## _show, inode->i_private); \ +} + +#define DEFINE_TRACE_REMOTE_ATTRIBUTE(__name) \ +DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static const struct file_operations __name ## _fops = { \ + .open = __name ## _open, \ + .read = seq_read, \ + .write = __name ## _write, \ + .llseek = seq_lseek, \ + .release = single_release, \ +} + +#define DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(__name) \ +DEFINE_TRACE_REMOTE_ATTRIBUTE_FUNCS(__name) \ +static const struct file_operations __name ## _fops = { \ + .open = __name ## _open, \ + .read = seq_read, \ + .llseek = seq_lseek, \ + .release = single_release, \ +} + static ssize_t tracing_on_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { @@ -198,7 +256,7 @@ static int tracing_on_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_STORE_ATTRIBUTE(tracing_on); +DEFINE_TRACE_REMOTE_ATTRIBUTE(tracing_on); static ssize_t buffer_size_kb_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -235,7 +293,7 @@ static int buffer_size_kb_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_STORE_ATTRIBUTE(buffer_size_kb); +DEFINE_TRACE_REMOTE_ATTRIBUTE(buffer_size_kb); static int trace_remote_get(struct trace_remote *remote, int cpu) { @@ -593,6 +651,11 @@ static int trace_pipe_open(struct inode *inode, struct file *filp) struct trace_remote *remote = inode->i_private; struct trace_remote_iterator *iter; int cpu = tracing_get_cpu(inode); + int ret; + + ret = trace_remote_tracefs_open(inode, filp); + if (ret) + return ret; guard(mutex)(&remote->lock); @@ -734,22 +797,26 @@ static int trace_open(struct inode *inode, struct file *filp) int cpu = tracing_get_cpu(inode); int ret; + ret = trace_remote_tracefs_open(inode, filp); + if (ret) + return ret; + if (!(filp->f_mode & FMODE_READ)) return 0; + ret = seq_open(filp, &trace_sops); + if (ret) + return ret; + guard(mutex)(&remote->lock); iter = trace_remote_iter(remote, cpu, TRI_NONCONSUMING); - if (IS_ERR(iter)) + if (IS_ERR(iter)) { + seq_release(inode, filp); return PTR_ERR(iter); - - ret = seq_open(filp, &trace_sops); - if (ret) { - trace_remote_iter_free(iter); - return ret; } - ((struct seq_file *)filp->private_data)->private = (void *)iter; + ((struct seq_file *)filp->private_data)->private = iter; return 0; } @@ -932,8 +999,12 @@ int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, } ret = cbs->init ? cbs->init(remote->dentry, priv) : 0; - if (ret) + if (ret) { pr_err("Init failed for trace remote '%s' (%d)\n", name, ret); + } else { + guard(mutex)(&trace_remotes_lock); + list_add(&remote->node, &trace_remotes); + } return ret; } @@ -1073,7 +1144,7 @@ static ssize_t remote_event_enable_write(struct file *filp, const char __user *u return count; } -DEFINE_SHOW_STORE_ATTRIBUTE(remote_event_enable); +DEFINE_TRACE_REMOTE_ATTRIBUTE(remote_event_enable); static int remote_event_id_show(struct seq_file *s, void *unused) { @@ -1083,7 +1154,7 @@ static int remote_event_id_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_ATTRIBUTE(remote_event_id); +DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(remote_event_id); static int remote_event_format_show(struct seq_file *s, void *unused) { @@ -1112,7 +1183,7 @@ static int remote_event_format_show(struct seq_file *s, void *unused) return 0; } -DEFINE_SHOW_ATTRIBUTE(remote_event_format); +DEFINE_TRACE_REMOTE_SHOW_ATTRIBUTE(remote_event_format); static int remote_event_callback(const char *name, umode_t *mode, void **data, const struct file_operations **fops) @@ -1198,6 +1269,7 @@ static ssize_t remote_events_dir_enable_read(struct file *filp, char __user *ubu } static const struct file_operations remote_events_dir_enable_fops = { + .open = trace_remote_tracefs_open, .write = remote_events_dir_enable_write, .read = remote_events_dir_enable_read, }; @@ -1222,6 +1294,7 @@ remote_events_dir_header_page_read(struct file *filp, char __user *ubuf, size_t } static const struct file_operations remote_events_dir_header_page_fops = { + .open = trace_remote_tracefs_open, .read = remote_events_dir_header_page_read, }; @@ -1245,6 +1318,7 @@ remote_events_dir_header_event_read(struct file *filp, char __user *ubuf, size_t } static const struct file_operations remote_events_dir_header_event_fops = { + .open = trace_remote_tracefs_open, .read = remote_events_dir_header_event_read, }; -- 2.56.0.455.g6c5a503b38-goog