From a473573964e51dcb6efc182f773cd3924be4a184 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 21 Mar 2024 09:36:33 -0700 Subject: [PATCH] lib: code tagging module support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support for code tagging from dynamically loaded modules. Link: https://lkml.kernel.org/r/20240321163705.3067592-12-surenb@google.com Signed-off-by: Suren Baghdasaryan Co-developed-by: Kent Overstreet Signed-off-by: Kent Overstreet Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton --- include/linux/codetag.h | 12 +++++++++ kernel/module/main.c | 4 +++ lib/codetag.c | 58 +++++++++++++++++++++++++++++++++++++++-- 3 files changed, 72 insertions(+), 2 deletions(-) diff --git a/include/linux/codetag.h b/include/linux/codetag.h index 7734269cdb63..c44f5b83f24d 100644 --- a/include/linux/codetag.h +++ b/include/linux/codetag.h @@ -33,6 +33,10 @@ union codetag_ref { struct codetag_type_desc { const char *section; size_t tag_size; + void (*module_load)(struct codetag_type *cttype, + struct codetag_module *cmod); + void (*module_unload)(struct codetag_type *cttype, + struct codetag_module *cmod); }; struct codetag_iterator { @@ -65,4 +69,12 @@ void codetag_to_text(struct seq_buf *out, struct codetag *ct); struct codetag_type * codetag_register_type(const struct codetag_type_desc *desc); +#if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) +void codetag_load_module(struct module *mod); +void codetag_unload_module(struct module *mod); +#else +static inline void codetag_load_module(struct module *mod) {} +static inline void codetag_unload_module(struct module *mod) {} +#endif + #endif /* _LINUX_CODETAG_H */ diff --git a/kernel/module/main.c b/kernel/module/main.c index e1e8a7a9d6c1..ffa6b3e9cb43 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -1242,6 +1243,7 @@ static void free_module(struct module *mod) { trace_module_free(mod); + codetag_unload_module(mod); mod_sysfs_teardown(mod); /* @@ -2995,6 +2997,8 @@ static int load_module(struct load_info *info, const char __user *uargs, /* Get rid of temporary copy. */ free_copy(info, flags); + codetag_load_module(mod); + /* Done! */ trace_module_load(mod); diff --git a/lib/codetag.c b/lib/codetag.c index 8b5b89ad508d..54d2828eba25 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -124,15 +124,20 @@ static void *get_symbol(struct module *mod, const char *prefix, const char *name { DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN); const char *buf; + void *ret; seq_buf_printf(&sb, "%s%s", prefix, name); if (seq_buf_has_overflowed(&sb)) return NULL; buf = seq_buf_str(&sb); - return mod ? + preempt_disable(); + ret = mod ? (void *)find_kallsyms_symbol_value(mod, buf) : (void *)kallsyms_lookup_name(buf); + preempt_enable(); + + return ret; } static struct codetag_range get_section_range(struct module *mod, @@ -173,8 +178,11 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) down_write(&cttype->mod_lock); err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL); - if (err >= 0) + if (err >= 0) { cttype->count += range_size(cttype, &range); + if (cttype->desc.module_load) + cttype->desc.module_load(cttype, cmod); + } up_write(&cttype->mod_lock); if (err < 0) { @@ -185,6 +193,52 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) return 0; } +void codetag_load_module(struct module *mod) +{ + struct codetag_type *cttype; + + if (!mod) + return; + + mutex_lock(&codetag_lock); + list_for_each_entry(cttype, &codetag_types, link) + codetag_module_init(cttype, mod); + mutex_unlock(&codetag_lock); +} + +void codetag_unload_module(struct module *mod) +{ + struct codetag_type *cttype; + + if (!mod) + return; + + mutex_lock(&codetag_lock); + list_for_each_entry(cttype, &codetag_types, link) { + struct codetag_module *found = NULL; + struct codetag_module *cmod; + unsigned long mod_id, tmp; + + down_write(&cttype->mod_lock); + idr_for_each_entry_ul(&cttype->mod_idr, cmod, tmp, mod_id) { + if (cmod->mod && cmod->mod == mod) { + found = cmod; + break; + } + } + if (found) { + if (cttype->desc.module_unload) + cttype->desc.module_unload(cttype, cmod); + + cttype->count -= range_size(cttype, &cmod->range); + idr_remove(&cttype->mod_idr, mod_id); + kfree(cmod); + } + up_write(&cttype->mod_lock); + } + mutex_unlock(&codetag_lock); +} + #else /* CONFIG_MODULES */ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) { return 0; } #endif /* CONFIG_MODULES */