From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/kallsyms.c | 121 ++++++++++++++++++++++++++--------------
1 files changed, 78 insertions(+), 43 deletions(-)
diff --git a/kernel/kernel/kallsyms.c b/kernel/kernel/kallsyms.c
index b8ec1db..9650511 100644
--- a/kernel/kernel/kallsyms.c
+++ b/kernel/kernel/kallsyms.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
*
@@ -23,6 +24,7 @@
#include <linux/slab.h>
#include <linux/filter.h>
#include <linux/ftrace.h>
+#include <linux/kprobes.h>
#include <linux/compiler.h>
/*
@@ -37,16 +39,16 @@
* Tell the compiler that the count isn't in the small data section if the arch
* has one (eg: FRV).
*/
-extern const unsigned long kallsyms_num_syms
-__attribute__((weak, section(".rodata")));
+extern const unsigned int kallsyms_num_syms
+__section(".rodata") __attribute__((weak));
extern const unsigned long kallsyms_relative_base
-__attribute__((weak, section(".rodata")));
+__section(".rodata") __attribute__((weak));
-extern const u8 kallsyms_token_table[] __weak;
+extern const char kallsyms_token_table[] __weak;
extern const u16 kallsyms_token_index[] __weak;
-extern const unsigned long kallsyms_markers[] __weak;
+extern const unsigned int kallsyms_markers[] __weak;
/*
* Expand a compressed symbol data into the resulting uncompressed string,
@@ -57,7 +59,8 @@
char *result, size_t maxlen)
{
int len, skipped_first = 0;
- const u8 *tptr, *data;
+ const char *tptr;
+ const u8 *data;
/* Get the compressed symbol length from the first symbol byte. */
data = &kallsyms_names[off];
@@ -158,6 +161,26 @@
return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
}
+#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_LTO_CLANG_THIN)
+/*
+ * LLVM appends a hash to static function names when ThinLTO and CFI are
+ * both enabled, which causes confusion and potentially breaks user space
+ * tools, so we will strip the postfix from expanded symbol names.
+ */
+static inline char *cleanup_symbol_name(char *s)
+{
+ char *res = NULL;
+
+ res = strrchr(s, '$');
+ if (res)
+ *res = '\0';
+
+ return res;
+}
+#else
+static inline char *cleanup_symbol_name(char *s) { return NULL; }
+#endif
+
/* Lookup the address for this symbol. Returns 0 if not found. */
unsigned long kallsyms_lookup_name(const char *name)
{
@@ -169,6 +192,9 @@
off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (strcmp(namebuf, name) == 0)
+ return kallsyms_sym_address(i);
+
+ if (cleanup_symbol_name(namebuf) && strcmp(namebuf, name) == 0)
return kallsyms_sym_address(i);
}
return module_kallsyms_lookup_name(name);
@@ -267,30 +293,6 @@
return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf) ||
!!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
}
-
-#ifdef CONFIG_CFI_CLANG
-/*
- * LLVM appends .cfi to function names when CONFIG_CFI_CLANG is enabled,
- * which causes confusion and potentially breaks user space tools, so we
- * will strip the postfix from expanded symbol names.
- */
-static inline void cleanup_symbol_name(char *s)
-{
- char *res;
-
-#ifdef CONFIG_THINLTO
- /* Filter out hashes from static functions */
- res = strrchr(s, '$');
- if (res)
- *res = '\0';
-#endif
- res = strrchr(s, '.');
- if (res && !strcmp(res, ".cfi"))
- *res = '\0';
-}
-#else
-static inline void cleanup_symbol_name(char *s) {}
-#endif
/*
* Lookup an address
@@ -480,6 +482,7 @@
loff_t pos_arch_end;
loff_t pos_mod_end;
loff_t pos_ftrace_mod_end;
+ loff_t pos_bpf_end;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols. */
char type;
@@ -523,6 +526,11 @@
return 1;
}
+/*
+ * ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace
+ * purposes. In that case "__builtin__ftrace" is used as a module name, even
+ * though "__builtin__ftrace" is not a module.
+ */
static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
{
int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
@@ -539,11 +547,33 @@
static int get_ksymbol_bpf(struct kallsym_iter *iter)
{
- iter->module_name[0] = '\0';
+ int ret;
+
+ strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN);
iter->exported = 0;
- return bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
- &iter->value, &iter->type,
- iter->name) < 0 ? 0 : 1;
+ ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
+ &iter->value, &iter->type,
+ iter->name);
+ if (ret < 0) {
+ iter->pos_bpf_end = iter->pos;
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * This uses "__builtin__kprobes" as a module name for symbols for pages
+ * allocated for kprobes' purposes, even though "__builtin__kprobes" is not a
+ * module.
+ */
+static int get_ksymbol_kprobe(struct kallsym_iter *iter)
+{
+ strlcpy(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,
+ iter->name) < 0 ? 0 : 1;
}
/* Returns space to next name. */
@@ -570,6 +600,7 @@
iter->pos_arch_end = 0;
iter->pos_mod_end = 0;
iter->pos_ftrace_mod_end = 0;
+ iter->pos_bpf_end = 0;
}
}
@@ -594,7 +625,11 @@
get_ksymbol_ftrace_mod(iter))
return 1;
- return get_ksymbol_bpf(iter);
+ if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&
+ get_ksymbol_bpf(iter))
+ return 1;
+
+ return get_ksymbol_kprobe(iter);
}
/* Returns false if pos at or past end of file. */
@@ -693,12 +728,12 @@
case 0:
if (kallsyms_for_perf())
return true;
- /* fallthrough */
+ fallthrough;
case 1:
if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
CAP_OPT_NOAUDIT) == 0)
return true;
- /* fallthrough */
+ fallthrough;
default:
return false;
}
@@ -745,16 +780,16 @@
}
#endif /* CONFIG_KGDB_KDB */
-static const struct file_operations kallsyms_operations = {
- .open = kallsyms_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release_private,
+static const struct proc_ops kallsyms_proc_ops = {
+ .proc_open = kallsyms_open,
+ .proc_read = seq_read,
+ .proc_lseek = seq_lseek,
+ .proc_release = seq_release_private,
};
static int __init kallsyms_init(void)
{
- proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
+ proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops);
return 0;
}
device_initcall(kallsyms_init);
--
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