X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fexec.c;h=ba112bd4a339c93995b66bd639175a37c95a084b;hb=57ecb34febc4c133ca0ccc7817796605a78a01d3;hp=434dba778ccc761befe61c26a62f26037993ba32;hpb=cdd6c482c9ff9c55475ee7392ec8f672eddb7be6;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/exec.c b/fs/exec.c index 434dba7..ba112bd 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -55,6 +55,7 @@ #include #include #include +#include #include #include @@ -63,6 +64,7 @@ int core_uses_pid; char core_pattern[CORENAME_MAX_SIZE] = "core"; +unsigned int core_pipe_limit; int suid_dumpable = 0; /* The maximal length of core_pattern is also specified in sysctl.c */ @@ -622,10 +624,8 @@ int setup_arg_pages(struct linux_binprm *bprm, /* Move stack pages down in memory. */ if (stack_shift) { ret = shift_arg_pages(vma, stack_shift); - if (ret) { - up_write(&mm->mmap_sem); - return ret; - } + if (ret) + goto out_unlock; } #ifdef CONFIG_STACK_GROWSUP @@ -639,7 +639,7 @@ int setup_arg_pages(struct linux_binprm *bprm, out_unlock: up_write(&mm->mmap_sem); - return 0; + return ret; } EXPORT_SYMBOL(setup_arg_pages); @@ -845,6 +845,9 @@ static int de_thread(struct task_struct *tsk) sig->notify_count = 0; no_thread_group: + if (current->mm) + setmax_mm_hiwater_rss(&sig->maxrss, current->mm); + exit_itimers(sig); flush_itimer_signals(); @@ -1354,6 +1357,8 @@ int do_execve(char * filename, if (retval < 0) goto out; + current->stack_start = current->mm->start_stack; + /* execve succeeded */ current->fs->in_exec = 0; current->in_execve = 0; @@ -1388,18 +1393,16 @@ out_ret: return retval; } -int set_binfmt(struct linux_binfmt *new) +void set_binfmt(struct linux_binfmt *new) { - struct linux_binfmt *old = current->binfmt; + struct mm_struct *mm = current->mm; - if (new) { - if (!try_module_get(new->module)) - return -1; - } - current->binfmt = new; - if (old) - module_put(old->module); - return 0; + if (mm->binfmt) + module_put(mm->binfmt->module); + + mm->binfmt = new; + if (new) + __module_get(new->module); } EXPORT_SYMBOL(set_binfmt); @@ -1723,6 +1726,29 @@ int get_dumpable(struct mm_struct *mm) return (ret >= 2) ? 2 : ret; } +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); + +} + + void do_coredump(long signr, int exit_code, struct pt_regs *regs) { struct core_state core_state; @@ -1739,11 +1765,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; char **helper_argv = NULL; int helper_argc = 0; - char *delimit; + int dump_count = 0; + static atomic_t core_dump_count = ATOMIC_INIT(0); audit_core_dumps(signr); - binfmt = current->binfmt; + binfmt = mm->binfmt; if (!binfmt || !binfmt->core_dump) goto fail; @@ -1794,54 +1821,63 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) lock_kernel(); ispipe = format_corename(corename, signr); unlock_kernel(); - /* - * Don't bother to check the RLIMIT_CORE value if core_pattern points - * to a pipe. Since we're not writing directly to the filesystem - * RLIMIT_CORE doesn't really apply, as no actual core file will be - * created unless the pipe reader choses to write out the core file - * at which point file size limits and permissions will be imposed - * as it does with any other process - */ + if ((!ispipe) && (core_limit < binfmt->min_coredump)) goto fail_unlock; if (ispipe) { + if (core_limit == 0) { + /* + * Normally core limits are irrelevant to pipes, since + * we're not writing to the file system, but we use + * core_limit of 0 here as a speacial value. Any + * non-zero limit gets set to RLIM_INFINITY below, but + * a limit of 0 skips the dump. This is a consistent + * way to catch recursive crashes. We can still crash + * if the core_pattern binary sets RLIM_CORE = !0 + * 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 0\n", + task_tgid_vnr(current), current->comm); + printk(KERN_WARNING "Aborting core\n"); + goto fail_unlock; + } + + 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, corename+1, &helper_argc); if (!helper_argv) { printk(KERN_WARNING "%s failed to allocate memory\n", __func__); - goto fail_unlock; - } - /* Terminate the string before the first option */ - delimit = strchr(corename, ' '); - if (delimit) - *delimit = '\0'; - delimit = strrchr(helper_argv[0], '/'); - if (delimit) - delimit++; - else - delimit = helper_argv[0]; - if (!strcmp(delimit, current->comm)) { - printk(KERN_NOTICE "Recursive core dump detected, " - "aborting\n"); - goto fail_unlock; + goto fail_dropcount; } core_limit = RLIM_INFINITY; /* SIGPIPE can happen, but it's just never processed */ - if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, + if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL, &file)) { printk(KERN_INFO "Core dump to %s pipe failed\n", corename); - goto fail_unlock; + goto fail_dropcount; } } else file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600); if (IS_ERR(file)) - goto fail_unlock; + goto fail_dropcount; inode = file->f_path.dentry->d_inode; if (inode->i_nlink > 1) goto close_fail; /* multiple links - don't dump */ @@ -1870,7 +1906,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) if (retval) current->signal->group_exit_code |= 0x80; close_fail: + if (ispipe && core_pipe_limit) + wait_for_dump_helpers(file); filp_close(file, NULL); +fail_dropcount: + if (dump_count) + atomic_dec(&core_dump_count); fail_unlock: if (helper_argv) argv_free(helper_argv);