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authorAl Viro <viro@zeniv.linux.org.uk>2017-09-29 13:43:15 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2017-09-29 13:43:15 -0400
commit6c85501f2fabcfc4fc6ed976543d252c4eaf4be9 (patch)
tree7ae62970c63295669f955f60b78dbada3e564d30
parentb776e4b1a990045a7c70798f1f353c3160c26594 (diff)
fix infoleak in waitid(2)
kernel_waitid() can return a PID, an error or 0. rusage is filled in the first case and waitid(2) rusage should've been copied out exactly in that case, *not* whenever kernel_waitid() has not returned an error. Compat variant shares that braino; none of kernel_wait4() callers do, so the below ought to fix it. Reported-and-tested-by: Alexander Potapenko <glider@google.com> Fixes: ce72a16fa705 ("wait4(2)/waitid(2): separate copying rusage to userland") Cc: stable@vger.kernel.org # v4.13 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--kernel/exit.c23
1 files changed, 10 insertions, 13 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 3481ababd06a..f2cd53e92147 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1600,12 +1600,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
struct waitid_info info = {.status = 0};
long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
int signo = 0;
+
if (err > 0) {
signo = SIGCHLD;
err = 0;
- }
-
- if (!err) {
if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
return -EFAULT;
}
@@ -1723,16 +1721,15 @@ COMPAT_SYSCALL_DEFINE5(waitid,
if (err > 0) {
signo = SIGCHLD;
err = 0;
- }
-
- if (!err && uru) {
- /* kernel_waitid() overwrites everything in ru */
- if (COMPAT_USE_64BIT_TIME)
- err = copy_to_user(uru, &ru, sizeof(ru));
- else
- err = put_compat_rusage(&ru, uru);
- if (err)
- return -EFAULT;
+ if (uru) {
+ /* kernel_waitid() overwrites everything in ru */
+ if (COMPAT_USE_64BIT_TIME)
+ err = copy_to_user(uru, &ru, sizeof(ru));
+ else
+ err = put_compat_rusage(&ru, uru);
+ if (err)
+ return -EFAULT;
+ }
}
if (!infop)