[PATCH AUTOSEL 4.14 2/6] audit: fix undefined behavior in bit shift for AUDIT_BIT

From: Gaosheng Cui <cuigaosheng1(a)huawei.com&gt; [ Upstream commit 986d93f55bdeab1cac858d1e47b41fac10b2d7f6 ] Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in kernel/auditfilter.c:179:23 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c audit_register_class+0x9d/0x137 audit_classes_init+0x4d/0xb8 do_one_initcall+0x76/0x430 kernel_init_freeable+0x3b3/0x422 kernel_init+0x24/0x1e0 ret_from_fork+0x1f/0x30 </TASK> Signed-off-by: Gaosheng Cui <cuigaosheng1(a)huawei.com&gt; [PM: remove bad 'Fixes' tag as issue predates git, added in v2.6.6-rc1] Signed-off-by: Paul Moore <paul(a)paul-moore.com&gt; Signed-off-by: Sasha Levin <sashal(a)kernel.org&gt; --- include/uapi/linux/audit.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 7668582db6ba..68847af5e16d 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -172,7 +172,7 @@ #define AUDIT_MAX_KEY_LEN 256 #define AUDIT_BITMASK_SIZE 64 #define AUDIT_WORD(nr) ((__u32)((nr)/32)) -#define AUDIT_BIT(nr) (1 << ((nr) - AUDIT_WORD(nr)*32)) +#define AUDIT_BIT(nr) (1U << ((nr) - AUDIT_WORD(nr)*32)) #define AUDIT_SYSCALL_CLASSES 16 #define AUDIT_CLASS_DIR_WRITE 0 -- 2.35.1