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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-09-18 23:51:43 -0700
committerThomas Gleixner <tglx@linutronix.de>2018-09-27 17:56:49 +0200
commite872267b8bcbb179e21ccc7118f258873d6e7a59 (patch)
tree144867ffb2c030b4eb70d2b02f3646293ed73d83
parent19483677684b6ca01606f58503cb79cdfbbc7c72 (diff)
downloadlinux-e872267b8bcbb179e21ccc7118f258873d6e7a59.tar.bz2
jump_table: Move entries into ro_after_init region
The __jump_table sections emitted into the core kernel and into each module consist of statically initialized references into other parts of the code, and with the exception of entries that point into init code, which are defused at post-init time, these data structures are never modified. So let's move them into the ro_after_init section, to prevent them from being corrupted inadvertently by buggy code, or deliberately by an attacker. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Jessica Yu <jeyu@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: https://lkml.kernel.org/r/20180919065144.25010-9-ard.biesheuvel@linaro.org
-rw-r--r--arch/s390/kernel/vmlinux.lds.S1
-rw-r--r--include/asm-generic/vmlinux.lds.h11
-rw-r--r--kernel/module.c9
3 files changed, 17 insertions, 4 deletions
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index b43f8d33a369..4042bbf3f9ad 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -66,6 +66,7 @@ SECTIONS
*(.data..ro_after_init)
}
EXCEPTION_TABLE(16)
+ JUMP_TABLE_DATA
. = ALIGN(PAGE_SIZE);
__end_ro_after_init = .;
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 7b75ff6e2fce..f09ee3c544bc 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -253,10 +253,6 @@
STRUCT_ALIGN(); \
*(__tracepoints) \
/* implement dynamic printk debug */ \
- . = ALIGN(8); \
- __start___jump_table = .; \
- KEEP(*(__jump_table)) \
- __stop___jump_table = .; \
. = ALIGN(8); \
__start___verbose = .; \
KEEP(*(__verbose)) \
@@ -300,6 +296,12 @@
. = __start_init_task + THREAD_SIZE; \
__end_init_task = .;
+#define JUMP_TABLE_DATA \
+ . = ALIGN(8); \
+ __start___jump_table = .; \
+ KEEP(*(__jump_table)) \
+ __stop___jump_table = .;
+
/*
* Allow architectures to handle ro_after_init data on their
* own by defining an empty RO_AFTER_INIT_DATA.
@@ -308,6 +310,7 @@
#define RO_AFTER_INIT_DATA \
__start_ro_after_init = .; \
*(.data..ro_after_init) \
+ JUMP_TABLE_DATA \
__end_ro_after_init = .;
#endif
diff --git a/kernel/module.c b/kernel/module.c
index 6746c85511fe..49a405891587 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3317,6 +3317,15 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
ndx = find_sec(info, ".data..ro_after_init");
if (ndx)
info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
+ /*
+ * Mark the __jump_table section as ro_after_init as well: these data
+ * structures are never modified, with the exception of entries that
+ * refer to code in the __init section, which are annotated as such
+ * at module load time.
+ */
+ ndx = find_sec(info, "__jump_table");
+ if (ndx)
+ info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any