linux-kernel - [PATCH] MIPS: Ignore relocs against __ex

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20250226132841.381063-1-xry111@xry111.site>
Date: Wed, 26 Feb 2025 21:28:41 +0800
From: Xi Ruoyao <xry111@...111.site>
To: Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Jiaxun Yang <jiaxun.yang@...goat.com>
Cc: Matt Redfearn <matt.redfearn@...ize.com>,
	linux-mips@...r.kernel.org,
	linux-kbuild@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Xi Ruoyao <xry111@...111.site>
Subject: [PATCH] MIPS: Ignore relocs against __ex_table for relocatable kernel

Since commit 6f2c2f93a190 ("scripts/sorttable: Remove unneeded
Elf_Rel"), sorttable no longer clears relocs against __ex_table,
claiming "it was never used."  But in fact MIPS relocatable kernel had
been implicitly depending on this behavior, so after this commit the
MIPS relocatable kernel has started to spit oops like:

	CPU 1 Unable to handle kernel paging request at virtual address 000000fffbbdbff8, epc == ffffffff818f9a6c, ra == ffffffff813ad7d0
	... ...
	Call Trace:
	[<ffffffff818f9a6c>] __raw_copy_from_user+0x48/0x2fc
	[<ffffffff813ad7d0>] cp_statx+0x1a0/0x1e0
	[<ffffffff813ae528>] do_statx_fd+0xa8/0x118
	[<ffffffff813ae670>] sys_statx+0xd8/0xf8
	[<ffffffff81156cc8>] syscall_common+0x34/0x58

So ignore those relocs on our own to fix the issue.

Fixes: 6f2c2f93a190 ("scripts/sorttable: Remove unneeded Elf_Rel")
Signed-off-by: Xi Ruoyao <xry111@...111.site>
---
 arch/mips/boot/tools/relocs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/boot/tools/relocs.c b/arch/mips/boot/tools/relocs.c
index a88d66c46d7f..9863e1d5c62e 100644
--- a/arch/mips/boot/tools/relocs.c
+++ b/arch/mips/boot/tools/relocs.c
@@ -468,6 +468,8 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 			Elf_Sym *sym, const char *symname))
 {
 	int i;
+	struct section *extab_sec = sec_lookup("__ex_table");
+	int extab_index = extab_sec ? extab_sec - secs : -1;
 
 	/* Walk through the relocations */
 	for (i = 0; i < ehdr.e_shnum; i++) {
@@ -480,6 +482,9 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 		if (sec->shdr.sh_type != SHT_REL_TYPE)
 			continue;
 
+		if (sec->shdr.sh_info == extab_index)
+			continue;
+
 		sec_symtab  = sec->link;
 		sec_applies = &secs[sec->shdr.sh_info];
 		if (!(sec_applies->shdr.sh_flags & SHF_ALLOC))
-- 
2.48.1