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| author | Andrei Vagin <avagin@gmail.com> | 2019-03-28 20:44:13 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-04 09:21:23 +0200 |
| commit | 107cfb99c81f37a8df6dc4726495db7b5e22967f (patch) | |
| tree | f6447ff8b36a5e0257663f79230772c437e559d6 /kernel | |
| parent | 87eaf3d8ac51577c6123b43245e547c94c54dc06 (diff) | |
| download | linux-stable-107cfb99c81f37a8df6dc4726495db7b5e22967f.tar.gz linux-stable-107cfb99c81f37a8df6dc4726495db7b5e22967f.tar.bz2 linux-stable-107cfb99c81f37a8df6dc4726495db7b5e22967f.zip | |
ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK
[ Upstream commit fcfc2aa0185f4a731d05a21e9f359968fdfd02e7 ]
There are a few system calls (pselect, ppoll, etc) which replace a task
sigmask while they are running in a kernel-space
When a task calls one of these syscalls, the kernel saves a current
sigmask in task->saved_sigmask and sets a syscall sigmask.
On syscall-exit-stop, ptrace traps a task before restoring the
saved_sigmask, so PTRACE_GETSIGMASK returns the syscall sigmask and
PTRACE_SETSIGMASK does nothing, because its sigmask is replaced by
saved_sigmask, when the task returns to user-space.
This patch fixes this problem. PTRACE_GETSIGMASK returns saved_sigmask
if it's set. PTRACE_SETSIGMASK drops the TIF_RESTORE_SIGMASK flag.
Link: http://lkml.kernel.org/r/20181120060616.6043-1-avagin@gmail.com
Fixes: 29000caecbe8 ("ptrace: add ability to get/set signal-blocked mask")
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/ptrace.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 771e93f9c43f..6f357f4fc859 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -29,6 +29,7 @@ #include <linux/hw_breakpoint.h> #include <linux/cn_proc.h> #include <linux/compat.h> +#include <linux/sched/signal.h> /* * Access another process' address space via ptrace. @@ -924,18 +925,26 @@ int ptrace_request(struct task_struct *child, long request, ret = ptrace_setsiginfo(child, &siginfo); break; - case PTRACE_GETSIGMASK: + case PTRACE_GETSIGMASK: { + sigset_t *mask; + if (addr != sizeof(sigset_t)) { ret = -EINVAL; break; } - if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t))) + if (test_tsk_restore_sigmask(child)) + mask = &child->saved_sigmask; + else + mask = &child->blocked; + + if (copy_to_user(datavp, mask, sizeof(sigset_t))) ret = -EFAULT; else ret = 0; break; + } case PTRACE_SETSIGMASK: { sigset_t new_set; @@ -961,6 +970,8 @@ int ptrace_request(struct task_struct *child, long request, child->blocked = new_set; spin_unlock_irq(&child->sighand->siglock); + clear_tsk_restore_sigmask(child); + ret = 0; break; } |