Commit 6c85501f authored by Al Viro's avatar Al Viro

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: default avatarAlexander Potapenko <glider@google.com>
Fixes: ce72a16f ("wait4(2)/waitid(2): separate copying rusage to userland")
Cc: stable@vger.kernel.org # v4.13
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b776e4b1
...@@ -1600,12 +1600,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, ...@@ -1600,12 +1600,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
struct waitid_info info = {.status = 0}; struct waitid_info info = {.status = 0};
long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL); long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
int signo = 0; int signo = 0;
if (err > 0) { if (err > 0) {
signo = SIGCHLD; signo = SIGCHLD;
err = 0; err = 0;
}
if (!err) {
if (ru && copy_to_user(ru, &r, sizeof(struct rusage))) if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
return -EFAULT; return -EFAULT;
} }
...@@ -1723,16 +1721,15 @@ COMPAT_SYSCALL_DEFINE5(waitid, ...@@ -1723,16 +1721,15 @@ COMPAT_SYSCALL_DEFINE5(waitid,
if (err > 0) { if (err > 0) {
signo = SIGCHLD; signo = SIGCHLD;
err = 0; err = 0;
} if (uru) {
/* kernel_waitid() overwrites everything in ru */
if (!err && uru) { if (COMPAT_USE_64BIT_TIME)
/* kernel_waitid() overwrites everything in ru */ err = copy_to_user(uru, &ru, sizeof(ru));
if (COMPAT_USE_64BIT_TIME) else
err = copy_to_user(uru, &ru, sizeof(ru)); err = put_compat_rusage(&ru, uru);
else if (err)
err = put_compat_rusage(&ru, uru); return -EFAULT;
if (err) }
return -EFAULT;
} }
if (!infop) if (!infop)
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment