diff options
Diffstat (limited to 'kernel/kallsyms.c')
| -rw-r--r-- | kernel/kallsyms.c | 127 |
1 files changed, 16 insertions, 111 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 77747391f49b..18edd57b5fe8 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -163,42 +163,36 @@ unsigned long kallsyms_sym_address(int idx) return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; } -static bool cleanup_symbol_name(char *s) +static void cleanup_symbol_name(char *s) { char *res; if (!IS_ENABLED(CONFIG_LTO_CLANG)) - return false; + return; /* * LLVM appends various suffixes for local functions and variables that * must be promoted to global scope as part of LTO. This can break * hooking of static functions with kprobes. '.' is not a valid - * character in an identifier in C. Suffixes observed: + * character in an identifier in C. Suffixes only in LLVM LTO observed: * - foo.llvm.[0-9a-f]+ - * - foo.[0-9a-f]+ */ - res = strchr(s, '.'); - if (res) { + res = strstr(s, ".llvm."); + if (res) *res = '\0'; - return true; - } - return false; + return; } static int compare_symbol_name(const char *name, char *namebuf) { - int ret; - - ret = strcmp(name, namebuf); - if (!ret) - return ret; - - if (cleanup_symbol_name(namebuf) && !strcmp(name, namebuf)) - return 0; - - return ret; + /* The kallsyms_seqs_of_names is sorted based on names after + * cleanup_symbol_name() (see scripts/kallsyms.c) if clang lto is enabled. + * To ensure correct bisection in kallsyms_lookup_names(), do + * cleanup_symbol_name(namebuf) before comparing name and namebuf. + */ + cleanup_symbol_name(namebuf); + return strcmp(name, namebuf); } static unsigned int get_symbol_seq(int index) @@ -484,34 +478,6 @@ found: return 0; } -int lookup_symbol_attrs(unsigned long addr, unsigned long *size, - unsigned long *offset, char *modname, char *name) -{ - int res; - - name[0] = '\0'; - name[KSYM_NAME_LEN - 1] = '\0'; - - if (is_ksym_addr(addr)) { - unsigned long pos; - - pos = get_symbol_pos(addr, size, offset); - /* Grab name */ - kallsyms_expand_symbol(get_symbol_offset(pos), - name, KSYM_NAME_LEN); - modname[0] = '\0'; - goto found; - } - /* See if it's in a module. */ - res = lookup_module_symbol_attrs(addr, size, offset, modname, name); - if (res) - return res; - -found: - cleanup_symbol_name(name); - return 0; -} - /* Look up a kernel symbol and return it in a text buffer. */ static int __sprint_symbol(char *buffer, unsigned long address, int symbol_offset, int add_offset, int add_buildid) @@ -646,7 +612,6 @@ int sprint_backtrace_build_id(char *buffer, unsigned long address) /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ struct kallsym_iter { loff_t pos; - loff_t pos_arch_end; loff_t pos_mod_end; loff_t pos_ftrace_mod_end; loff_t pos_bpf_end; @@ -659,29 +624,9 @@ struct kallsym_iter { int show_value; }; -int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value, - char *type, char *name) -{ - return -EINVAL; -} - -static int get_ksymbol_arch(struct kallsym_iter *iter) -{ - int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms, - &iter->value, &iter->type, - iter->name); - - if (ret < 0) { - iter->pos_arch_end = iter->pos; - return 0; - } - - return 1; -} - static int get_ksymbol_mod(struct kallsym_iter *iter) { - int ret = module_get_kallsym(iter->pos - iter->pos_arch_end, + int ret = module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value, &iter->type, iter->name, iter->module_name, &iter->exported); @@ -716,7 +661,7 @@ static int get_ksymbol_bpf(struct kallsym_iter *iter) { int ret; - strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN); + strscpy(iter->module_name, "bpf", MODULE_NAME_LEN); iter->exported = 0; ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end, &iter->value, &iter->type, @@ -736,7 +681,7 @@ static int get_ksymbol_bpf(struct kallsym_iter *iter) */ static int get_ksymbol_kprobe(struct kallsym_iter *iter) { - strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN); + strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN); iter->exported = 0; return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end, &iter->value, &iter->type, @@ -764,7 +709,6 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) iter->nameoff = get_symbol_offset(new_pos); iter->pos = new_pos; if (new_pos == 0) { - iter->pos_arch_end = 0; iter->pos_mod_end = 0; iter->pos_ftrace_mod_end = 0; iter->pos_bpf_end = 0; @@ -780,10 +724,6 @@ static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) { iter->pos = pos; - if ((!iter->pos_arch_end || iter->pos_arch_end > pos) && - get_ksymbol_arch(iter)) - return 1; - if ((!iter->pos_mod_end || iter->pos_mod_end > pos) && get_ksymbol_mod(iter)) return 1; @@ -961,41 +901,6 @@ late_initcall(bpf_ksym_iter_register); #endif /* CONFIG_BPF_SYSCALL */ -static inline int kallsyms_for_perf(void) -{ -#ifdef CONFIG_PERF_EVENTS - extern int sysctl_perf_event_paranoid; - if (sysctl_perf_event_paranoid <= 1) - return 1; -#endif - return 0; -} - -/* - * We show kallsyms information even to normal users if we've enabled - * kernel profiling and are explicitly not paranoid (so kptr_restrict - * is clear, and sysctl_perf_event_paranoid isn't set). - * - * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to - * block even that). - */ -bool kallsyms_show_value(const struct cred *cred) -{ - switch (kptr_restrict) { - case 0: - if (kallsyms_for_perf()) - return true; - fallthrough; - case 1: - if (security_capable(cred, &init_user_ns, CAP_SYSLOG, - CAP_OPT_NOAUDIT) == 0) - return true; - fallthrough; - default: - return false; - } -} - static int kallsyms_open(struct inode *inode, struct file *file) { /* |