From: Richard W.M. Jones Date: Tue, 9 Oct 2012 14:27:43 +0000 (+0100) Subject: dup3: Return an error when oldfd == newfd. X-Git-Tag: firefly_0821_release~3680^2~1846^2~14 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=aed976475bff939672b0e21595839c445dcec0fa;p=firefly-linux-kernel-4.4.55.git dup3: Return an error when oldfd == newfd. I have tested the attached patch to fix the dup3 regression. Rich. From 0944e30e12dec6544b3602626b60ff412375c78f Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Tue, 9 Oct 2012 14:42:45 +0100 Subject: [PATCH] dup3: Return an error when oldfd == newfd. The following commit: commit fe17f22d7fd0e344ef6447238f799bb49f670c6f Author: Al Viro Date: Tue Aug 21 11:48:11 2012 -0400 take purely descriptor-related stuff from fcntl.c to file.c was supposed to be just code motion, but it dropped the following two lines: if (unlikely(oldfd == newfd)) return -EINVAL; from the dup3 system call. dup3 is not specified by POSIX, so Linux can do what it likes. However the POSIX proposal for dup3 [1] states that it should return an error if oldfd == newfd. [1] http://austingroupbugs.net/view.php?id=411 Signed-off-by: Richard W.M. Jones Tested-by: Richard W.M. Jones Signed-off-by: Al Viro --- diff --git a/fs/file.c b/fs/file.c index 0f1bda4bebfa..d3b5fa80b71b 100644 --- a/fs/file.c +++ b/fs/file.c @@ -922,6 +922,9 @@ SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) if ((flags & ~O_CLOEXEC) != 0) return -EINVAL; + if (unlikely(oldfd == newfd)) + return -EINVAL; + if (newfd >= rlimit(RLIMIT_NOFILE)) return -EMFILE;