From 2b79bc4f7ebbd5af3c8b867968f9f15602d5f802 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Mon, 11 May 2009 14:25:34 -0400 Subject: [PATCH] dup2: Fix return value with oldfd == newfd and invalid fd The return value of dup2 when oldfd == newfd and the fd isn't valid is not getting properly sign extended. We end up with 4294967287 instead of -EBADF. I've reproduced this on SLE11 (2.6.27.21), openSUSE Factory (2.6.29-rc5), and Ubuntu 9.04 (2.6.28). This patch uses a signed int for the error value so it is properly extended. Commit 6c5d0512a091480c9f981162227fdb1c9d70e555 introduced this regression. Reported-by: Jiri Dluhos Signed-off-by: Jeff Mahoney Signed-off-by: Linus Torvalds --- fs/fcntl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index cc8e4de2fee5..1ad703150dee 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -117,11 +117,13 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) { if (unlikely(newfd == oldfd)) { /* corner case */ struct files_struct *files = current->files; + int retval = oldfd; + rcu_read_lock(); if (!fcheck_files(files, oldfd)) - oldfd = -EBADF; + retval = -EBADF; rcu_read_unlock(); - return oldfd; + return retval; } return sys_dup3(oldfd, newfd, 0); }