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xtensa: fix signal delivery to FDPIC process 

Fetch function descriptor pointed to by the signal handler pointer from
userspace on signal delivery and function pointer pointed to by the
sa_restorer on return from the signal handler.

Cc: stable@vger.kernel.org
Fixes: e3ddb8bbe0 ("xtensa: add FDPIC and static PIE support for noMMU")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2023-05-02 03:20:47 -07:00
parent 457391b038
commit 9c2cc74fb3
1 changed files with 27 additions and 8 deletions
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35
arch/xtensa/kernel/signal.c
View File

@ -343,7 +343,19 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
struct rt_sigframe *frame;
int err = 0, sig = ksig->sig;
unsigned long sp, ra, tp, ps;
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
unsigned long handler_fdpic_GOT = 0;
unsigned int base;
bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
(current->personality & FDPIC_FUNCPTRS);
if (fdpic) {
unsigned long __user *fdpic_func_desc =
(unsigned long __user *)handler;
if (__get_user(handler, &fdpic_func_desc[0]) ||
__get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
return -EFAULT;
}
sp = regs->areg[1];
@ -373,20 +385,26 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
ra = (unsigned long)ksig->ka.sa.sa_restorer;
if (fdpic) {
unsigned long __user *fdpic_func_desc =
(unsigned long __user *)ksig->ka.sa.sa_restorer;
err |= __get_user(ra, fdpic_func_desc);
} else {
ra = (unsigned long)ksig->ka.sa.sa_restorer;
}
} else {
/* Create sys_rt_sigreturn syscall in stack frame */
err |= gen_return_code(frame->retcode);
if (err) {
return -EFAULT;
}
ra = (unsigned long) frame->retcode;
}
/*
if (err)
return -EFAULT;
/*
* Create signal handler execution context.
* Return context not modified until this point.
*/
@ -394,8 +412,7 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
/* Set up registers for signal handler; preserve the threadptr */
tp = regs->threadptr;
ps = regs->ps;
start_thread(regs, (unsigned long) ksig->ka.sa.sa_handler,
(unsigned long) frame);
start_thread(regs, handler, (unsigned long)frame);
/* Set up a stack frame for a call4 if userspace uses windowed ABI */
if (ps & PS_WOE_MASK) {
@ -413,6 +430,8 @@ static int setup_frame(struct ksignal *ksig, sigset_t *set,
regs->areg[base + 4] = (unsigned long) &frame->uc;
regs->threadptr = tp;
regs->ps = ps;
if (fdpic)
regs->areg[base + 11] = handler_fdpic_GOT;
pr_debug("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08lx\n",
current->comm, current->pid, sig, frame, regs->pc);