cp: should filter mode bits on newly created object

[jtyler76]

In cp, the newly created object (the copy) is created using the mode bits of the source object (

toybox/toys/posix/cp.c

Line 296 in fb3ca98

fdout = openat(cfd, catch, O_RDWR|O_CREAT|O_TRUNC, try->st.st_mode);

). The issue is that the mode of the source object may have bits set that are not file permission bits, and POSIX states that the effect of setting such bits in open()/openat() is unspecified (see the POSIX spec page for open()/openat() when it describes O_CREAT).

The mode bits passed to openat() in the aforementioned line should be filtered down to only the file permission bits as listed on the <sys/stat.h> page of the POSIX spec.

[landley]

On 11/25/24 14:09, jtyler76 wrote: The `mode` bits passed to `openat()` in the aforementioned line should be filtered down to only the file permission bits as listed on the `<sys/stat.h>` page of the POSIX spec.

What use case broke on which system?