[REVIEW][PATCH 26/26] signal: Remove the signal number and task parameters from force_sig_info

From: Eric W. Biederman
Date: Wed May 22 2019 - 20:46:39 EST


force_sig_info always delivers to the current task and the signal
parameter always matches info.si_signo. So remove those parameters to
make it a simpler less error prone interface, and to make it clear
that none of the callers are doing anything clever.

This guarantees that force_sig_info will not grow any new buggy
callers that attempt to call force_sig on a non-current task, or that
pass an signal number that does not match info.si_signo.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
include/linux/ptrace.h | 2 +-
include/linux/sched/signal.h | 2 +-
kernel/seccomp.c | 2 +-
kernel/signal.c | 14 +++++++-------
4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index d5084ebd9f03..2a9df80ea887 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -355,7 +355,7 @@ static inline void user_single_step_report(struct pt_regs *regs)
info.si_code = SI_USER;
info.si_pid = 0;
info.si_uid = 0;
- force_sig_info(info.si_signo, &info, current);
+ force_sig_info(&info);
}
#endif

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 7f872506e1de..532458698bde 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -329,7 +329,7 @@ int force_sig_ptrace_errno_trap(int errno, void __user *addr);

extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
extern void force_sigsegv(int sig);
-extern int force_sig_info(int, struct kernel_siginfo *, struct task_struct *);
+extern int force_sig_info(struct kernel_siginfo *);
extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
extern int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr, struct pid *,
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 811b4a86cdf6..dba52a7db5e8 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -609,7 +609,7 @@ static void seccomp_send_sigsys(int syscall, int reason)
{
struct kernel_siginfo info;
seccomp_init_siginfo(&info, syscall, reason);
- force_sig_info(SIGSYS, &info, current);
+ force_sig_info(&info);
}
#endif /* CONFIG_SECCOMP_FILTER */

diff --git a/kernel/signal.c b/kernel/signal.c
index 0984158cd41a..ff6944e4964e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1325,9 +1325,9 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
return ret;
}

-int force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t)
+int force_sig_info(struct kernel_siginfo *info)
{
- return force_sig_info_to_task(info, t);
+ return force_sig_info_to_task(info, current);
}

/*
@@ -1619,7 +1619,7 @@ void force_sig(int sig)
info.si_code = SI_KERNEL;
info.si_pid = 0;
info.si_uid = 0;
- force_sig_info(info.si_signo, &info, current);
+ force_sig_info(&info);
}
EXPORT_SYMBOL(force_sig);

@@ -1708,7 +1708,7 @@ int force_sig_mceerr(int code, void __user *addr, short lsb)
info.si_code = code;
info.si_addr = addr;
info.si_addr_lsb = lsb;
- return force_sig_info(info.si_signo, &info, current);
+ return force_sig_info(&info);
}

int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
@@ -1737,7 +1737,7 @@ int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
info.si_addr = addr;
info.si_lower = lower;
info.si_upper = upper;
- return force_sig_info(info.si_signo, &info, current);
+ return force_sig_info(&info);
}

#ifdef SEGV_PKUERR
@@ -1751,7 +1751,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
info.si_code = SEGV_PKUERR;
info.si_addr = addr;
info.si_pkey = pkey;
- return force_sig_info(info.si_signo, &info, current);
+ return force_sig_info(&info);
}
#endif

@@ -1767,7 +1767,7 @@ int force_sig_ptrace_errno_trap(int errno, void __user *addr)
info.si_errno = errno;
info.si_code = TRAP_HWBKPT;
info.si_addr = addr;
- return force_sig_info(info.si_signo, &info, current);
+ return force_sig_info(&info);
}

int kill_pgrp(struct pid *pid, int sig, int priv)
--
2.21.0