From a4a2a427413e350bd01505f1f698b80545e1be58 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sun, 4 Sep 2022 15:40:54 -0600 Subject: dyndbg: validate class FOO by checking with module Add module-to-class validation: #> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control If a query has "class FOO", then ddebug_find_valid_class(), called from ddebug_change(), requires that FOO is known to module X, otherwize the query is skipped entirely for X. This protects each module's class-space, other than the default:31. The authors' choice of FOO is highly selective, giving isolation and/or coordinated sharing of FOOs. For example, only DRM modules should know and respond to DRM_UT_KMS. So this, combined with module's opt-in declaration of known classes, effectively privatizes the .class_id space for each module (or coordinated set of modules). Notes: For all "class FOO" queries, ddebug_find_valid_class() is called, it returns the map matching the query, and sets valid_class via an *outvar). If no "class FOO" is supplied, valid_class = _CLASS_DFLT. This insures that legacy queries do not trample on new class'd callsites, as they get added. Also add a new column to control-file output, displaying non-default class-name (when found) or the "unknown _id:", if it has not been (correctly) declared with one of the declarator macros. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-18-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- lib/dynamic_debug.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 68 insertions(+), 8 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index b71efd0b491d..db96ded78c3f 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -56,6 +56,7 @@ struct ddebug_query { const char *module; const char *function; const char *format; + const char *class_string; unsigned int first_lineno, last_lineno; }; @@ -136,15 +137,33 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg) fmtlen--; } - v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n", - msg, - query->function ?: "", - query->filename ?: "", - query->module ?: "", - fmtlen, query->format ?: "", - query->first_lineno, query->last_lineno); + v3pr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u class=%s\n", + msg, + query->function ?: "", + query->filename ?: "", + query->module ?: "", + fmtlen, query->format ?: "", + query->first_lineno, query->last_lineno, query->class_string); } +static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt, + const char *class_string, int *class_id) +{ + struct ddebug_class_map *map; + int idx; + + list_for_each_entry(map, &dt->maps, link) { + idx = match_string(map->class_names, map->length, class_string); + if (idx >= 0) { + *class_id = idx + map->base; + return map; + } + } + *class_id = -ENOENT; + return NULL; +} + +#define __outvar /* filled by callee */ /* * Search the tables for _ddebug's which match the given `query' and * apply the `flags' and `mask' to them. Returns number of matching @@ -159,6 +178,8 @@ static int ddebug_change(const struct ddebug_query *query, unsigned int newflags; unsigned int nfound = 0; struct flagsbuf fbuf, nbuf; + struct ddebug_class_map *map = NULL; + int __outvar valid_class; /* search for matching ddebugs */ mutex_lock(&ddebug_lock); @@ -169,9 +190,22 @@ static int ddebug_change(const struct ddebug_query *query, !match_wildcard(query->module, dt->mod_name)) continue; + if (query->class_string) { + map = ddebug_find_valid_class(dt, query->class_string, &valid_class); + if (!map) + continue; + } else { + /* constrain query, do not touch class'd callsites */ + valid_class = _DPRINTK_CLASS_DFLT; + } + for (i = 0; i < dt->num_ddebugs; i++) { struct _ddebug *dp = &dt->ddebugs[i]; + /* match site against query-class */ + if (dp->class_id != valid_class) + continue; + /* match against the source filename */ if (query->filename && !match_wildcard(query->filename, dp->filename) && @@ -420,6 +454,8 @@ static int ddebug_parse_query(char *words[], int nwords, } else if (!strcmp(keyword, "line")) { if (parse_linerange(query, arg)) return -EINVAL; + } else if (!strcmp(keyword, "class")) { + rc = check_set(&query->class_string, arg, "class"); } else { pr_err("unknown keyword \"%s\"\n", keyword); return -EINVAL; @@ -854,6 +890,20 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos) return dp; } +#define class_in_range(class_id, map) \ + (class_id >= map->base && class_id < map->base + map->length) + +static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp) +{ + struct ddebug_class_map *map; + + list_for_each_entry(map, &iter->table->maps, link) + if (class_in_range(dp->class_id, map)) + return map->class_names[dp->class_id - map->base]; + + return NULL; +} + /* * Seq_ops show method. Called several times within a read() * call from userspace, with ddebug_lock held. Formats the @@ -865,6 +915,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p) struct ddebug_iter *iter = m->private; struct _ddebug *dp = p; struct flagsbuf flags; + char const *class; if (p == SEQ_START_TOKEN) { seq_puts(m, @@ -877,7 +928,16 @@ static int ddebug_proc_show(struct seq_file *m, void *p) iter->table->mod_name, dp->function, ddebug_describe_flags(dp->flags, &flags)); seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\""); - seq_puts(m, "\"\n"); + seq_puts(m, "\""); + + if (dp->class_id != _DPRINTK_CLASS_DFLT) { + class = ddebug_class_name(iter, dp); + if (class) + seq_printf(m, " class:%s", class); + else + seq_printf(m, " class unknown, _id:%d", dp->class_id); + } + seq_puts(m, "\n"); return 0; } -- cgit v1.2.3