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authorMarco Elver <elver@google.com>2020-12-14 19:09:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:42 -0800
commit6d5a88cd0c1506115d71a4d3a26b60645c89df6c (patch)
tree7cd83ff57ac5b24aa1e1ef0a4291c7049dadcae6 /drivers/misc
parent4784be284adaa516df4144fc919f9bde8200443a (diff)
lkdtm: disable KASAN for rodata.o
Building lkdtm with KASAN and Clang 11 or later results in the following error when attempting to load the module: kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffffffc019cd70 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation ... RIP: 0010:asan.module_ctor+0x0/0xffffffffffffa290 [lkdtm] ... Call Trace: do_init_module+0x17c/0x570 load_module+0xadee/0xd0b0 __x64_sys_finit_module+0x16c/0x1a0 do_syscall_64+0x34/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The reason is that rodata.o generates a dummy function that lives in .rodata to validate that .rodata can't be executed; however, Clang 11 adds KASAN globals support by generating module constructors to initialize globals redzones. When Clang 11 adds a module constructor to rodata.o, it is also added to .rodata: any attempt to call it on initialization results in the above error. Therefore, disable KASAN instrumentation for rodata.o. Link: https://lkml.kernel.org/r/20201214191413.3164796-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/lkdtm/Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index c70b3822013f..1c4c7aca0026 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -11,6 +11,7 @@ lkdtm-$(CONFIG_LKDTM) += usercopy.o
lkdtm-$(CONFIG_LKDTM) += stackleak.o
lkdtm-$(CONFIG_LKDTM) += cfi.o
+KASAN_SANITIZE_rodata.o := n
KASAN_SANITIZE_stackleak.o := n
KCOV_INSTRUMENT_rodata.o := n