Hi Al,
Today's linux-next merge of the signal tree got a conflict in fs/exec.c
between commit 5b8a94d461a7 ("coredump: move core dump functionality into
its own file") from the vfs tree and commits 70446600fa12 ("arm:
introduce ret_from_kernel_execve(), switch to generic kernel_execve()")
and 5e41814a7d8b ("arm: get rid of execve wrapper, switch to generic
execve() implementation") from the signal tree.I fixed it up (see below) and can carry the fix as necessary (no action is required). BTW, Al, you have that vfs tree commit (and others) authored by you ... -- Cheers, Stephen Rothwell [email protected] diff --cc fs/exec.c index 48fb26e,df8b282..0000000 --- a/fs/exec.c +++ b/fs/exec.c @@@ -1645,3 -2031,345 +1644,58 @@@ int get_dumpable(struct mm_struct *mm { return __get_dumpable(mm->flags); } + -static void wait_for_dump_helpers(struct file *file) -{ - struct pipe_inode_info *pipe; - - pipe = file->f_path.dentry->d_inode->i_pipe; - - pipe_lock(pipe); - pipe->readers++; - pipe->writers--; - - while ((pipe->readers > 1) && (!signal_pending(current))) { - wake_up_interruptible_sync(&pipe->wait); - kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); - pipe_wait(pipe); - } - - pipe->readers--; - pipe->writers++; - pipe_unlock(pipe); - -} - - -/* - * umh_pipe_setup - * helper function to customize the process used - * to collect the core in userspace. Specifically - * it sets up a pipe and installs it as fd 0 (stdin) - * for the process. Returns 0 on success, or - * PTR_ERR on failure. - * Note that it also sets the core limit to 1. This - * is a special value that we use to trap recursive - * core dumps - */ -static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) -{ - struct file *files[2]; - struct fdtable *fdt; - struct coredump_params *cp = (struct coredump_params *)info->data; - struct files_struct *cf = current->files; - int err = create_pipe_files(files, 0); - if (err) - return err; - - cp->file = files[1]; - - sys_close(0); - fd_install(0, files[0]); - spin_lock(&cf->file_lock); - fdt = files_fdtable(cf); - __set_open_fd(0, fdt); - __clear_close_on_exec(0, fdt); - spin_unlock(&cf->file_lock); - - /* and disallow core files too */ - current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; - - return 0; -} - -void do_coredump(long signr, int exit_code, struct pt_regs *regs) -{ - struct core_state core_state; - struct core_name cn; - struct mm_struct *mm = current->mm; - struct linux_binfmt * binfmt; - const struct cred *old_cred; - struct cred *cred; - int retval = 0; - int flag = 0; - int ispipe; - bool need_nonrelative = false; - static atomic_t core_dump_count = ATOMIC_INIT(0); - struct coredump_params cprm = { - .signr = signr, - .regs = regs, - .limit = rlimit(RLIMIT_CORE), - /* - * We must use the same mm->flags while dumping core to avoid - * inconsistency of bit flags, since this flag is not protected - * by any locks. - */ - .mm_flags = mm->flags, - }; - - audit_core_dumps(signr); - - binfmt = mm->binfmt; - if (!binfmt || !binfmt->core_dump) - goto fail; - if (!__get_dumpable(cprm.mm_flags)) - goto fail; - - cred = prepare_creds(); - if (!cred) - goto fail; - /* - * We cannot trust fsuid as being the "true" uid of the process - * nor do we know its entire history. We only know it was tainted - * so we dump it as root in mode 2, and only into a controlled - * environment (pipe handler or fully qualified path). - */ - if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) { - /* Setuid core dump mode */ - flag = O_EXCL; /* Stop rewrite attacks */ - cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ - need_nonrelative = true; - } - - retval = coredump_wait(exit_code, &core_state); - if (retval < 0) - goto fail_creds; - - old_cred = override_creds(cred); - - /* - * Clear any false indication of pending signals that might - * be seen by the filesystem code called to write the core file. - */ - clear_thread_flag(TIF_SIGPENDING); - - ispipe = format_corename(&cn, signr); - - if (ispipe) { - int dump_count; - char **helper_argv; - - if (ispipe < 0) { - printk(KERN_WARNING "format_corename failed\n"); - printk(KERN_WARNING "Aborting core\n"); - goto fail_corename; - } - - if (cprm.limit == 1) { - /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. - * - * Normally core limits are irrelevant to pipes, since - * we're not writing to the file system, but we use - * cprm.limit of 1 here as a speacial value, this is a - * consistent way to catch recursive crashes. - * We can still crash if the core_pattern binary sets - * RLIM_CORE = !1, but it runs as root, and can do - * lots of stupid things. - * - * Note that we use task_tgid_vnr here to grab the pid - * of the process group leader. That way we get the - * right pid if a thread in a multi-threaded - * core_pattern process dies. - */ - printk(KERN_WARNING - "Process %d(%s) has RLIMIT_CORE set to 1\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Aborting core\n"); - goto fail_unlock; - } - cprm.limit = RLIM_INFINITY; - - dump_count = atomic_inc_return(&core_dump_count); - if (core_pipe_limit && (core_pipe_limit < dump_count)) { - printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); - goto fail_dropcount; - } - - helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); - if (!helper_argv) { - printk(KERN_WARNING "%s failed to allocate memory\n", - __func__); - goto fail_dropcount; - } - - retval = call_usermodehelper_fns(helper_argv[0], helper_argv, - NULL, UMH_WAIT_EXEC, umh_pipe_setup, - NULL, &cprm); - argv_free(helper_argv); - if (retval) { - printk(KERN_INFO "Core dump to %s pipe failed\n", - cn.corename); - goto close_fail; - } - } else { - struct inode *inode; - - if (cprm.limit < binfmt->min_coredump) - goto fail_unlock; - - if (need_nonrelative && cn.corename[0] != '/') { - printk(KERN_WARNING "Pid %d(%s) can only dump core "\ - "to fully qualified path!\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); - goto fail_unlock; - } - - cprm.file = filp_open(cn.corename, - O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, - 0600); - if (IS_ERR(cprm.file)) - goto fail_unlock; - - inode = cprm.file->f_path.dentry->d_inode; - if (inode->i_nlink > 1) - goto close_fail; - if (d_unhashed(cprm.file->f_path.dentry)) - goto close_fail; - /* - * AK: actually i see no reason to not allow this for named - * pipes etc, but keep the previous behaviour for now. - */ - if (!S_ISREG(inode->i_mode)) - goto close_fail; - /* - * Dont allow local users get cute and trick others to coredump - * into their pre-created files. - */ - if (!uid_eq(inode->i_uid, current_fsuid())) - goto close_fail; - if (!cprm.file->f_op || !cprm.file->f_op->write) - goto close_fail; - if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) - goto close_fail; - } - - retval = binfmt->core_dump(&cprm); - if (retval) - current->signal->group_exit_code |= 0x80; - - if (ispipe && core_pipe_limit) - wait_for_dump_helpers(cprm.file); -close_fail: - if (cprm.file) - filp_close(cprm.file, NULL); -fail_dropcount: - if (ispipe) - atomic_dec(&core_dump_count); -fail_unlock: - kfree(cn.corename); -fail_corename: - coredump_finish(mm); - revert_creds(old_cred); -fail_creds: - put_cred(cred); -fail: - return; -} - -/* - * Core dumping helper functions. These are the only things you should - * do on a core-file: use only these functions to write out all the - * necessary info. - */ -int dump_write(struct file *file, const void *addr, int nr) -{ - return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; -} -EXPORT_SYMBOL(dump_write); - -int dump_seek(struct file *file, loff_t off) -{ - int ret = 1; - - if (file->f_op->llseek && file->f_op->llseek != no_llseek) { - if (file->f_op->llseek(file, off, SEEK_CUR) < 0) - return 0; - } else { - char *buf = (char *)get_zeroed_page(GFP_KERNEL); - - if (!buf) - return 0; - while (off > 0) { - unsigned long n = off; - - if (n > PAGE_SIZE) - n = PAGE_SIZE; - if (!dump_write(file, buf, n)) { - ret = 0; - break; - } - off -= n; - } - free_page((unsigned long)buf); - } - return ret; -} -EXPORT_SYMBOL(dump_seek); - + #ifdef __ARCH_WANT_SYS_EXECVE + SYSCALL_DEFINE3(execve, + const char __user *, filename, + const char __user *const __user *, argv, + const char __user *const __user *, envp) + { + const char *path = getname(filename); + int error = PTR_ERR(path); + if (!IS_ERR(path)) { + error = do_execve(path, argv, envp, current_pt_regs()); + putname(path); + } + return error; + } + #ifdef CONFIG_COMPAT + asmlinkage long compat_sys_execve(const char __user * filename, + const compat_uptr_t __user * argv, + const compat_uptr_t __user * envp) + { + const char *path = getname(filename); + int error = PTR_ERR(path); + if (!IS_ERR(path)) { + error = compat_do_execve(path, argv, envp, current_pt_regs()); + putname(path); + } + return error; + } + #endif + #endif + + #ifdef __ARCH_WANT_KERNEL_EXECVE + int kernel_execve(const char *filename, + const char *const argv[], + const char *const envp[]) + { + struct pt_regs regs, *p; + int ret; + + memset(®s, 0, sizeof(struct pt_regs)); + ret = do_execve(filename, + (const char __user *const __user *)argv, + (const char __user *const __user *)envp, ®s); + if (ret < 0) + return ret; + + /* + * We were successful. We won't be returning to our caller, but + * instead to user space by manipulating the kernel stack. + */ + p = current_pt_regs(); + *p = regs; + ret_from_kernel_execve(p); + } + #endif
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