>From c99b7daafdbf1e2415bf408e67ca7813e7ddeedf Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 28 Feb 2023 12:21:23 -0500 Subject: [PATCH 2/2] fix dup3 ignoring all flags but O_CLOEXEC on archs with SYS_dup2 syscall our dup3 code wrongly skipped directly to making the SYS_dup2 syscall whenever the O_CLOEXEC bit of flags was not set. this is incorrect if any new flags are ever added, as it would silently ignore them rather than failing with an error. archs which lack SYS_dup2 were unaffected. adjust the logic so that SYS_dup3 is attempted whenever flags is nonzero, and explicitly fail with EINVAL if SYS_dup3 is unavailable and there are any unknown flags. --- src/unistd/dup3.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/unistd/dup3.c b/src/unistd/dup3.c index f919f791..1e7dc3e7 100644 --- a/src/unistd/dup3.c +++ b/src/unistd/dup3.c @@ -9,9 +9,10 @@ int __dup3(int old, int new, int flags) int r; #ifdef SYS_dup2 if (old==new) return __syscall_ret(-EINVAL); - if (flags & O_CLOEXEC) { + if (flags) { while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY); if (r!=-ENOSYS) return __syscall_ret(r); + if (flags & ~O_CLOEXEC) return __syscall_ret(-EINVAL); } while ((r=__syscall(SYS_dup2, old, new))==-EBUSY); if (flags & O_CLOEXEC) __syscall(SYS_fcntl, new, F_SETFD, FD_CLOEXEC); -- 2.21.0