Messages in this thread |  | | From | Andy Lutomirski <> | Date | Wed, 22 Oct 2014 11:44:29 -0700 | Subject | Re: [PATCHv5 1/3] syscalls,x86: implement execveat() system call |
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On Wed, Oct 22, 2014 at 4:44 AM, David Drysdale <drysdale@google.com> wrote: > Add a new system execveat(2) syscall. execveat() is to execve() as > openat() is to open(): it takes a file descriptor that refers to a > directory, and resolves the filename relative to that. >
> bprm->file = file; > - bprm->filename = bprm->interp = filename->name; > + if (fd == AT_FDCWD || filename->name[0] == '/') { > + bprm->filename = filename->name; > + } else { > + /* > + * Build a pathname that reflects how we got to the file, > + * either "/dev/fd/<fd>" (for an empty filename) or > + * "/dev/fd/<fd>/<filename>". > + */ > + pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); > + if (!pathbuf) { > + retval = -ENOMEM; > + goto out_unmark; > + } > + bprm->filename = pathbuf; > + if (filename->name[0] == '\0') > + sprintf(pathbuf, "/dev/fd/%d", fd);
If the fd is O_CLOEXEC, then this will result in a confused child process. Should we fail exec attempts like that for non-static programs? (E.g. set filename to "" or something and fix up the binfmt drivers to handle that?)
> + else > + snprintf(pathbuf, PATH_MAX, > + "/dev/fd/%d/%s", fd, filename->name);
Does this need to handle the case where the result exceeds PATH_MAX?
--Andy
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