From 5b835d4cade1723c5944a231cc685801f5a5cc6c Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Sat, 5 Mar 2022 21:05:54 -0800 Subject: xtensa: use XCHAL_NUM_AREGS as pt_regs::areg size struct pt_regs is used to access both kernel and user exception frames. User exception frames may contain up to XCHAL_NUM_AREG registers that task creation and signal delivery code may access, but pt_regs::areg array has only 16 entries that cover only the kernel exception frame. This results in the following build error: arch/xtensa/kernel/process.c: In function 'copy_thread': arch/xtensa/kernel/process.c:262:52: error: array subscript 53 is above array bounds of 'long unsigned int[16]' [-Werror=array-bounds] 262 | put_user(regs->areg[caller_ars+1], Change struct pt_regs::areg size to XCHAL_NUM_AREGS so that it covers the whole user exception frame. Adjust task_pt_regs and drop additional register copying code from copy_thread now that the whole user exception stack frame is copied. Reported-by: Kees Cook Signed-off-by: Max Filippov Reviewed-by: Kees Cook --- arch/xtensa/include/asm/ptrace.h | 7 +++---- arch/xtensa/kernel/process.c | 10 ---------- 2 files changed, 3 insertions(+), 14 deletions(-) (limited to 'arch/xtensa') diff --git a/arch/xtensa/include/asm/ptrace.h b/arch/xtensa/include/asm/ptrace.h index b109416dc07e..308f209a4740 100644 --- a/arch/xtensa/include/asm/ptrace.h +++ b/arch/xtensa/include/asm/ptrace.h @@ -44,6 +44,7 @@ #ifndef __ASSEMBLY__ #include +#include /* * This struct defines the way the registers are stored on the @@ -77,14 +78,12 @@ struct pt_regs { /* current register frame. * Note: The ESF for kernel exceptions ends after 16 registers! */ - unsigned long areg[16]; + unsigned long areg[XCHAL_NUM_AREGS]; }; -#include - # define arch_has_single_step() (1) # define task_pt_regs(tsk) ((struct pt_regs*) \ - (task_stack_page(tsk) + KERNEL_STACK_SIZE - (XCHAL_NUM_AREGS-16)*4) - 1) + (task_stack_page(tsk) + KERNEL_STACK_SIZE) - 1) # define user_mode(regs) (((regs)->ps & 0x00000020)!=0) # define instruction_pointer(regs) ((regs)->pc) # define return_pointer(regs) (MAKE_PC_FROM_RA((regs)->areg[0], \ diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index bd80df890b1e..e8bfbca5f001 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -232,10 +232,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, p->thread.ra = MAKE_RA_FOR_CALL( (unsigned long)ret_from_fork, 0x1); - /* This does not copy all the regs. - * In a bout of brilliance or madness, - * ARs beyond a0-a15 exist past the end of the struct. - */ *childregs = *regs; childregs->areg[1] = usp; childregs->areg[2] = 0; @@ -265,14 +261,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, childregs->wmask = 1; childregs->windowstart = 1; childregs->windowbase = 0; - } else { - int len = childregs->wmask & ~0xf; - memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4], - ®s->areg[XCHAL_NUM_AREGS - len/4], len); } - childregs->syscall = regs->syscall; - if (clone_flags & CLONE_SETTLS) childregs->threadptr = tls; } else { -- cgit