This is a note to let you know that I've just added the patch titled audit: fix undefined behavior in bit shift for AUDIT_BIT to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: audit-fix-undefined-behavior-in-bit-shift-for-audit_.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit da48ab9b9454525992586166403b626140a6db7a Author: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx> Date: Mon Oct 31 10:10:21 2022 +0800 audit: fix undefined behavior in bit shift for AUDIT_BIT [ 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@xxxxxxxxxx> [PM: remove bad 'Fixes' tag as issue predates git, added in v2.6.6-rc1] Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index cd2d8279a5e4..cb4e8e6e86a9 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -182,7 +182,7 @@ #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