diff options
| -rw-r--r-- | libbb/copy_file.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/libbb/copy_file.c b/libbb/copy_file.c index efb969f..86449f2 100644 --- a/libbb/copy_file.c +++ b/libbb/copy_file.c @@ -19,6 +19,9 @@ // (or fail, if it points to dir/nonexistent location/etc). // This is strange, but POSIX-correct. // coreutils cp has --remove-destination to override this... +// +// NB: we have special code which still allows for "cp file /dev/node" +// to work POSIX-ly (the only realistic case where it makes sense) #define DO_POSIX_CP 0 /* 1 - POSIX behavior, 0 - safe behavior */ @@ -243,13 +246,18 @@ int copy_file(const char *source, const char *dest, int flags) if (src_fd < 0) return -1; -#if DO_POSIX_CP /* POSIX way (a security problem versus symlink attacks!): */ - dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE) - ? O_WRONLY|O_CREAT|O_EXCL - : O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode); -#else /* safe way: */ - dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode); -#endif + /* POSIX way is a security problem versus symlink attacks, + * we do it only for dest's which are device nodes, + * and only for non-recursive, non-interactive cp. NB: it is still racy + * for "cp file /home/bad_user/device_node" case + * (user can rm device_node and create link to /etc/passwd) */ + if (DO_POSIX_CP + || (dest_exists && !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE)) + && (S_ISBLK(dest_stat.st_mode) || S_ISCHR(dest_stat.st_mode))) + ) { + dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode); + } else /* safe way: */ + dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode); if (dst_fd == -1) { ovr = ask_and_unlink(dest, flags); if (ovr <= 0) { |