linux-kernel - [PATCH v7 1/7] objtool: Handle various symbol types of rodata

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250211115016.26913-2-yangtiezhu@loongson.cn>
Date: Tue, 11 Feb 2025 19:50:10 +0800
From: Tiezhu Yang <yangtiezhu@...ngson.cn>
To: Josh Poimboeuf <jpoimboe@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH v7 1/7] objtool: Handle various symbol types of rodata

In the relocation section ".rela.rodata" of each .o file compiled with
LoongArch toolchain, there are various symbol types such as STT_NOTYPE,
STT_OBJECT, STT_FUNC in addition to the usual STT_SECTION, it needs to
use reloc symbol offset instead of reloc addend to find the destination
instruction in find_jump_table() and add_jump_table().

For the most part, an absolute relocation type is used for rodata. In the
case of STT_SECTION, reloc->sym->offset is always zero, and for the other
symbol types, reloc_addend(reloc) is always zero, thus it can use a simple
statement "reloc->sym->offset + reloc_addend(reloc)" to obtain the symbol
offset for various symbol types.

Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 tools/objtool/check.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 497cb8dfb3eb..a84e76e8eae4 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1953,6 +1953,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 	unsigned int prev_offset = 0;
 	struct reloc *reloc = table;
 	struct alternative *alt;
+	unsigned long sym_offset;
 
 	/*
 	 * Each @reloc is a switch table relocation which points to the target
@@ -1970,9 +1971,10 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)
 			break;
 
+		sym_offset = reloc->sym->offset + reloc_addend(reloc);
+
 		/* Detect function pointers from contiguous objects: */
-		if (reloc->sym->sec == pfunc->sec &&
-		    reloc_addend(reloc) == pfunc->offset)
+		if (reloc->sym->sec == pfunc->sec && sym_offset == pfunc->offset)
 			break;
 
 		/*
@@ -1980,10 +1982,10 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 		 * which point to the end of the function.  Ignore them.
 		 */
 		if (reloc->sym->sec == pfunc->sec &&
-		    reloc_addend(reloc) == pfunc->offset + pfunc->len)
+		    sym_offset == pfunc->offset + pfunc->len)
 			goto next;
 
-		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		dest_insn = find_insn(file, reloc->sym->sec, sym_offset);
 		if (!dest_insn)
 			break;
 
@@ -2022,6 +2024,7 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func,
 	struct reloc *table_reloc;
 	struct instruction *dest_insn, *orig_insn = insn;
 	unsigned long table_size;
+	unsigned long sym_offset;
 
 	/*
 	 * Backward search using the @first_jump_src links, these help avoid
@@ -2045,7 +2048,10 @@ static void find_jump_table(struct objtool_file *file, struct symbol *func,
 		table_reloc = arch_find_switch_table(file, insn, &table_size);
 		if (!table_reloc)
 			continue;
-		dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc));
+
+		sym_offset = table_reloc->sym->offset + reloc_addend(table_reloc);
+
+		dest_insn = find_insn(file, table_reloc->sym->sec, sym_offset);
 		if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)
 			continue;
 
-- 
2.42.0