[REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value
From: Eric W. Biederman <hidden>
Date: 2018-09-25 17:20:22
Also in:
linux-arch, lkml
Subsystem:
ptrace support, the rest · Maintainers:
Oleg Nesterov, Linus Torvalds
In preparation for using a smaller version of siginfo in the kernel introduce copy_siginfo_from_user and use it when siginfo is copied from userspace. Make the pattern for using copy_siginfo_from_user and copy_siginfo_from_user32 to capture the return value and return that value on error. This is a necessary prerequisite for using a smaller siginfo in the kernel than the kernel exports to userspace. Signed-off-by: "Eric W. Biederman" <redacted> --- include/linux/signal.h | 1 + kernel/ptrace.c | 12 +++++------- kernel/signal.c | 25 ++++++++++++++++--------- 3 files changed, 22 insertions(+), 16 deletions(-)
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 3d4cd5db30a9..de94c159bfb0 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h@@ -22,6 +22,7 @@ static inline void clear_siginfo(struct siginfo *info) } int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from); +int copy_siginfo_from_user(struct siginfo *to, const struct siginfo __user *from); enum siginfo_layout { SIL_KILL,
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 45f77a1b9c97..a807ff5cc1a9 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c@@ -919,9 +919,8 @@ int ptrace_request(struct task_struct *child, long request, break; case PTRACE_SETSIGINFO: - if (copy_from_user(&siginfo, datavp, sizeof siginfo)) - ret = -EFAULT; - else + ret = copy_siginfo_from_user(&siginfo, datavp); + if (!ret) ret = ptrace_setsiginfo(child, &siginfo); break;
@@ -1215,10 +1214,9 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, break; case PTRACE_SETSIGINFO: - if (copy_siginfo_from_user32( - &siginfo, (struct compat_siginfo __user *) datap)) - ret = -EFAULT; - else + ret = copy_siginfo_from_user32( + &siginfo, (struct compat_siginfo __user *) datap); + if (!ret) ret = ptrace_setsiginfo(child, &siginfo); break; #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
diff --git a/kernel/signal.c b/kernel/signal.c
index debb485a76db..c0e289e62d77 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c@@ -2896,6 +2896,13 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) return 0; } +int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from) +{ + if (copy_from_user(to, from, sizeof(struct siginfo))) + return -EFAULT; + return 0; +} + #ifdef CONFIG_COMPAT int copy_siginfo_to_user32(struct compat_siginfo __user *to, const struct siginfo *from)
@@ -3323,8 +3330,9 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, siginfo_t __user *, uinfo) { siginfo_t info; - if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) - return -EFAULT; + int ret = copy_siginfo_from_user(&info, uinfo); + if (unlikely(ret)) + return ret; return do_rt_sigqueueinfo(pid, sig, &info); }
@@ -3365,10 +3373,9 @@ SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig, siginfo_t __user *, uinfo) { siginfo_t info; - - if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) - return -EFAULT; - + int ret = copy_siginfo_from_user(&info, uinfo); + if (unlikely(ret)) + return ret; return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); }
@@ -3380,9 +3387,9 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, struct compat_siginfo __user *, uinfo) { siginfo_t info; - - if (copy_siginfo_from_user32(&info, uinfo)) - return -EFAULT; + int ret = copy_siginfo_from_user32(&info, uinfo); + if (unlikely(ret)) + return ret; return do_rt_tgsigqueueinfo(tgid, pid, sig, &info); } #endif
--
2.17.1