[PATCH 02/24] ptrace: Add compat PTRACE_{G,S}ETSIGMASK handlers
From: Yury Norov <hidden>
Date: 2018-05-16 08:20:02
Also in:
linux-arch, linux-arm-kernel, linux-doc, lkml
Subsystem:
ptrace support, the rest · Maintainers:
Oleg Nesterov, Linus Torvalds
From: James Morse <james.morse@arm.com>
compat_ptrace_request() lacks handlers for PTRACE_{G,S}ETSIGMASK,
instead using those in ptrace_request(). The compat variant should
read a compat_sigset_t from userspace instead of ptrace_request()s
sigset_t.
While compat_sigset_t is the same size as sigset_t, it is defined as
2xu32, instead of a single u64. On a big-endian CPU this means that
compat_sigset_t is passed to user-space using middle-endianness,
where the least-significant u32 is written most significant byte
first.
If ptrace_request()s code is used userspace will read the most
significant u32 where it expected the least significant.
Instead of duplicating ptrace_request()s code as a special case in
the arch code, handle it here.
Fixes: 29000caecbe87 ("ptrace: add ability to get/set signal-blocked mask")
CC: Andrey Vagin <redacted>
Signed-off-by: James Morse <james.morse@arm.com>
Yury:
Replace sigset_{to,from}_compat() with new {get,put}_compat_sigset()
Signed-off-by: Yury Norov <redacted>
---
kernel/ptrace.c | 48 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 36 insertions(+), 12 deletions(-)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 21fec73d45d4..214944d7c268 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c@@ -880,6 +880,22 @@ static int ptrace_regset(struct task_struct *task, int req, unsigned int type, EXPORT_SYMBOL_GPL(task_user_regset_view); #endif +static int ptrace_setsigmask(struct task_struct *child, sigset_t *new_set) +{ + sigdelsetmask(new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); + + /* + * Every thread does recalc_sigpending() after resume, so + * retarget_shared_pending() and recalc_sigpending() are not + * called here. + */ + spin_lock_irq(&child->sighand->siglock); + child->blocked = *new_set; + spin_unlock_irq(&child->sighand->siglock); + + return 0; +} + int ptrace_request(struct task_struct *child, long request, unsigned long addr, unsigned long data) {
@@ -951,18 +967,7 @@ int ptrace_request(struct task_struct *child, long request, break; } - sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); - - /* - * Every thread does recalc_sigpending() after resume, so - * retarget_shared_pending() and recalc_sigpending() are not - * called here. - */ - spin_lock_irq(&child->sighand->siglock); - child->blocked = new_set; - spin_unlock_irq(&child->sighand->siglock); - - ret = 0; + ret = ptrace_setsigmask(child, &new_set); break; }
@@ -1181,6 +1186,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, { compat_ulong_t __user *datap = compat_ptr(data); compat_ulong_t word; + sigset_t new_set; siginfo_t siginfo; int ret;
@@ -1221,6 +1227,24 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, else ret = ptrace_setsiginfo(child, &siginfo); break; + case PTRACE_GETSIGMASK: + if (addr != sizeof(compat_sigset_t)) + return -EINVAL; + + ret = put_compat_sigset((compat_sigset_t __user *) datap, + &child->blocked, sizeof(compat_sigset_t)); + break; + case PTRACE_SETSIGMASK: + if (addr != sizeof(compat_sigset_t)) + return -EINVAL; + + ret = get_compat_sigset(&new_set, + (compat_sigset_t __user *) datap); + if (ret) + break; + + ret = ptrace_setsigmask(child, &new_set); + break; #ifdef CONFIG_HAVE_ARCH_TRACEHOOK case PTRACE_GETREGSET: case PTRACE_SETREGSET:
--
2.17.0