From: Linus Torvalds torvalds@linux-foundation.org
mainline inclusion from mainline-v6.11-rc1 commit e78298556ee5d881f6679effb2a6743969ea6e2d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB2BWT CVE: CVE-2024-50102
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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This adds the initial dummy support for 'runtime constants' for when an architecture doesn't actually support an implementation of fixing up said runtime constants.
This ends up being the fallback to just using the variables as regular __ro_after_init variables, and changes the dcache d_hash() function to use this model.
Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Qi Xi xiqi2@huawei.com --- fs/dcache.c | 11 ++++++++++- include/asm-generic/Kbuild | 1 + include/asm-generic/runtime-const.h | 15 +++++++++++++++ include/asm-generic/vmlinux.lds.h | 8 ++++++++ 4 files changed, 34 insertions(+), 1 deletion(-) create mode 100644 include/asm-generic/runtime-const.h
diff --git a/fs/dcache.c b/fs/dcache.c index ff2bfc3af5b6..d58804e4939b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -35,6 +35,8 @@ #include "internal.h" #include "mount.h"
+#include <asm/runtime-const.h> + /* * Usage: * dcache->d_inode->i_lock protects: @@ -102,7 +104,8 @@ static struct hlist_bl_head *dentry_hashtable __read_mostly;
static inline struct hlist_bl_head *d_hash(unsigned long hashlen) { - return dentry_hashtable + ((u32)hashlen >> d_hash_shift); + return runtime_const_ptr(dentry_hashtable) + + runtime_const_shift_right_32(hashlen, d_hash_shift); }
#define IN_LOOKUP_SHIFT 10 @@ -3390,6 +3393,9 @@ static void __init dcache_init_early(void) 0, 0); d_hash_shift = 32 - d_hash_shift; + + runtime_const_init(shift, d_hash_shift); + runtime_const_init(ptr, dentry_hashtable); }
static void __init dcache_init(void) @@ -3418,6 +3424,9 @@ static void __init dcache_init(void) 0, 0); d_hash_shift = 32 - d_hash_shift; + + runtime_const_init(shift, d_hash_shift); + runtime_const_init(ptr, dentry_hashtable); }
/* SLAB cache for __getname() consumers */ diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index 941be574bbe0..22673ec5defb 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -46,6 +46,7 @@ mandatory-y += pci.h mandatory-y += percpu.h mandatory-y += pgalloc.h mandatory-y += preempt.h +mandatory-y += runtime-const.h mandatory-y += rwonce.h mandatory-y += sections.h mandatory-y += serial.h diff --git a/include/asm-generic/runtime-const.h b/include/asm-generic/runtime-const.h new file mode 100644 index 000000000000..670499459514 --- /dev/null +++ b/include/asm-generic/runtime-const.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +/* + * This is the fallback for when the architecture doesn't + * support the runtime const operations. + * + * We just use the actual symbols as-is. + */ +#define runtime_const_ptr(sym) (sym) +#define runtime_const_shift_right_32(val, sym) ((u32)(val)>>(sym)) +#define runtime_const_init(type,sym) do { } while (0) + +#endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 174d865ce46e..88ecb31df393 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -954,6 +954,14 @@ #define CON_INITCALL \ BOUNDED_SECTION_POST_LABEL(.con_initcall.init, __con_initcall, _start, _end)
+#define RUNTIME_NAME(t,x) runtime_##t##_##x + +#define RUNTIME_CONST(t,x) \ + . = ALIGN(8); \ + RUNTIME_NAME(t,x) : AT(ADDR(RUNTIME_NAME(t,x)) - LOAD_OFFSET) { \ + *(RUNTIME_NAME(t,x)); \ + } + /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */ #define KUNIT_TABLE() \ . = ALIGN(8); \