1 files changed, 113 insertions, 92 deletions

diff --git a/fs/coredump.c b/fs/coredump.c
index dafafbafa73..a93f7e6ea4c 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -40,74 +40,88 @@
 
 #include <trace/events/task.h>
 #include "internal.h"
-#include "coredump.h"
 
 #include <trace/events/sched.h>
 
 int core_uses_pid;
-char core_pattern[CORENAME_MAX_SIZE] = "core";
 unsigned int core_pipe_limit;
+char core_pattern[CORENAME_MAX_SIZE] = "core";
+static int core_name_size = CORENAME_MAX_SIZE;
 
 struct core_name {
 	char *corename;
 	int used, size;
 };
-static atomic_t call_count = ATOMIC_INIT(1);
 
 /* The maximal length of core_pattern is also specified in sysctl.c */
 
-static int expand_corename(struct core_name *cn)
+static int expand_corename(struct core_name *cn, int size)
 {
-	char *old_corename = cn->corename;
+	char *corename = krealloc(cn->corename, size, GFP_KERNEL);
 
-	cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
-	cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
-
-	if (!cn->corename) {
-		kfree(old_corename);
+	if (!corename)
 		return -ENOMEM;
-	}
 
+	if (size > core_name_size) /* racy but harmless */
+		core_name_size = size;
+
+	cn->size = ksize(corename);
+	cn->corename = corename;
 	return 0;
 }
 
+static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
+{
+	int free, need;
+	va_list arg_copy;
+
+again:
+	free = cn->size - cn->used;
+
+	va_copy(arg_copy, arg);
+	need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
+	va_end(arg_copy);
+
+	if (need < free) {
+		cn->used += need;
+		return 0;
+	}
+
+	if (!expand_corename(cn, cn->size + need - free + 1))
+		goto again;
+
+	return -ENOMEM;
+}
+
 static int cn_printf(struct core_name *cn, const char *fmt, ...)
 {
-	char *cur;
-	int need;
-	int ret;
 	va_list arg;
+	int ret;
 
 	va_start(arg, fmt);
-	need = vsnprintf(NULL, 0, fmt, arg);
+	ret = cn_vprintf(cn, fmt, arg);
 	va_end(arg);
 
-	if (likely(need < cn->size - cn->used - 1))
-		goto out_printf;
+	return ret;
+}
 
-	ret = expand_corename(cn);
-	if (ret)
-		goto expand_fail;
+static int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
+{
+	int cur = cn->used;
+	va_list arg;
+	int ret;
 
-out_printf:
-	cur = cn->corename + cn->used;
 	va_start(arg, fmt);
-	vsnprintf(cur, need + 1, fmt, arg);
+	ret = cn_vprintf(cn, fmt, arg);
 	va_end(arg);
-	cn->used += need;
-	return 0;
 
-expand_fail:
+	for (; cur < cn->used; ++cur) {
+		if (cn->corename[cur] == '/')
+			cn->corename[cur] = '!';
+	}
 	return ret;
 }
 
-static void cn_escape(char *str)
-{
-	for (; *str; str++)
-		if (*str == '/')
-			*str = '!';
-}
-
 static int cn_print_exe_file(struct core_name *cn)
 {
 	struct file *exe_file;
@@ -115,12 +129,8 @@ static int cn_print_exe_file(struct core_name *cn)
 	int ret;
 
 	exe_file = get_mm_exe_file(current->mm);
-	if (!exe_file) {
-		char *commstart = cn->corename + cn->used;
-		ret = cn_printf(cn, "%s (path unknown)", current->comm);
-		cn_escape(commstart);
-		return ret;
-	}
+	if (!exe_file)
+		return cn_esc_printf(cn, "%s (path unknown)", current->comm);
 
 	pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
 	if (!pathbuf) {
@@ -134,9 +144,7 @@ static int cn_print_exe_file(struct core_name *cn)
 		goto free_buf;
 	}
 
-	cn_escape(path);
-
-	ret = cn_printf(cn, "%s", path);
+	ret = cn_esc_printf(cn, "%s", path);
 
 free_buf:
 	kfree(pathbuf);
@@ -157,19 +165,19 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 	int pid_in_pattern = 0;
 	int err = 0;
 
-	cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
-	cn->corename = kmalloc(cn->size, GFP_KERNEL);
 	cn->used = 0;
-
-	if (!cn->corename)
+	cn->corename = NULL;
+	if (expand_corename(cn, core_name_size))
 		return -ENOMEM;
+	cn->corename[0] = '\0';
+
+	if (ispipe)
+		++pat_ptr;
 
 	/* Repeat as long as we have more pattern to process and more output
 	   space */
 	while (*pat_ptr) {
 		if (*pat_ptr != '%') {
-			if (*pat_ptr == 0)
-				goto out;
 			err = cn_printf(cn, "%c", *pat_ptr++);
 		} else {
 			switch (*++pat_ptr) {
@@ -186,6 +194,11 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 				err = cn_printf(cn, "%d",
 					      task_tgid_vnr(current));
 				break;
+			/* global pid */
+			case 'P':
+				err = cn_printf(cn, "%d",
+					      task_tgid_nr(current));
+				break;
 			/* uid */
 			case 'u':
 				err = cn_printf(cn, "%d", cred->uid);
@@ -210,22 +223,16 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 				break;
 			}
 			/* hostname */
-			case 'h': {
-				char *namestart = cn->corename + cn->used;
+			case 'h':
 				down_read(&uts_sem);
-				err = cn_printf(cn, "%s",
+				err = cn_esc_printf(cn, "%s",
 					      utsname()->nodename);
 				up_read(&uts_sem);
-				cn_escape(namestart);
 				break;
-			}
 			/* executable */
-			case 'e': {
-				char *commstart = cn->corename + cn->used;
-				err = cn_printf(cn, "%s", current->comm);
-				cn_escape(commstart);
+			case 'e':
+				err = cn_esc_printf(cn, "%s", current->comm);
 				break;
-			}
 			case 'E':
 				err = cn_print_exe_file(cn);
 				break;
@@ -244,6 +251,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 			return err;
 	}
 
+out:
 	/* Backward compatibility with core_uses_pid:
 	 *
 	 * If core_pattern does not include a %p (as is the default)
@@ -254,7 +262,6 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 		if (err)
 			return err;
 	}
-out:
 	return ispipe;
 }
 
@@ -299,7 +306,7 @@ static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
 	if (unlikely(nr < 0))
 		return nr;
 
-	tsk->flags = PF_DUMPCORE;
+	tsk->flags |= PF_DUMPCORE;
 	if (atomic_read(&mm->mm_users) == nr + 1)
 		goto done;
 	/*
@@ -482,7 +489,7 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 	return err;
 }
 
-void do_coredump(siginfo_t *siginfo)
+void do_coredump(const siginfo_t *siginfo)
 {
 	struct core_state core_state;
 	struct core_name cn;
@@ -549,7 +556,7 @@ void do_coredump(siginfo_t *siginfo)
 		if (ispipe < 0) {
 			printk(KERN_WARNING "format_corename failed\n");
 			printk(KERN_WARNING "Aborting core\n");
-			goto fail_corename;
+			goto fail_unlock;
 		}
 
 		if (cprm.limit == 1) {
@@ -584,7 +591,7 @@ void do_coredump(siginfo_t *siginfo)
 			goto fail_dropcount;
 		}
 
-		helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
+		helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
 		if (!helper_argv) {
 			printk(KERN_WARNING "%s failed to allocate memory\n",
 			       __func__);
@@ -601,7 +608,7 @@ void do_coredump(siginfo_t *siginfo)
 
 		argv_free(helper_argv);
 		if (retval) {
-			printk(KERN_INFO "Core dump to %s pipe failed\n",
+			printk(KERN_INFO "Core dump to |%s pipe failed\n",
 			       cn.corename);
 			goto close_fail;
 		}
@@ -642,7 +649,7 @@ void do_coredump(siginfo_t *siginfo)
 		 */
 		if (!uid_eq(inode->i_uid, current_fsuid()))
 			goto close_fail;
-		if (!cprm.file->f_op || !cprm.file->f_op->write)
+		if (!cprm.file->f_op->write)
 			goto close_fail;
 		if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
 			goto close_fail;
@@ -669,7 +676,6 @@ fail_dropcount:
 		atomic_dec(&core_dump_count);
 fail_unlock:
 	kfree(cn.corename);
-fail_corename:
 	coredump_finish(mm, core_dumped);
 	revert_creds(old_cred);
 fail_creds:
@@ -683,40 +689,55 @@ fail:
  * 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)
+int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
 {
-	return !dump_interrupted() &&
-		access_ok(VERIFY_READ, addr, nr) &&
-		file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+	struct file *file = cprm->file;
+	loff_t pos = file->f_pos;
+	ssize_t n;
+	if (cprm->written + nr > cprm->limit)
+		return 0;
+	while (nr) {
+		if (dump_interrupted())
+			return 0;
+		n = __kernel_write(file, addr, nr, &pos);
+		if (n <= 0)
+			return 0;
+		file->f_pos = pos;
+		cprm->written += n;
+		nr -= n;
+	}
+	return 1;
 }
-EXPORT_SYMBOL(dump_write);
+EXPORT_SYMBOL(dump_emit);
 
-int dump_seek(struct file *file, loff_t off)
+int dump_skip(struct coredump_params *cprm, size_t nr)
 {
-	int ret = 1;
-
+	static char zeroes[PAGE_SIZE];
+	struct file *file = cprm->file;
 	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
+		if (cprm->written + nr > cprm->limit)
+			return 0;
 		if (dump_interrupted() ||
-		    file->f_op->llseek(file, off, SEEK_CUR) < 0)
+		    file->f_op->llseek(file, nr, SEEK_CUR) < 0)
 			return 0;
+		cprm->written += nr;
+		return 1;
 	} 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;
+		while (nr > PAGE_SIZE) {
+			if (!dump_emit(cprm, zeroes, PAGE_SIZE))
+				return 0;
+			nr -= PAGE_SIZE;
 		}
-		free_page((unsigned long)buf);
+		return dump_emit(cprm, zeroes, nr);
 	}
-	return ret;
 }
-EXPORT_SYMBOL(dump_seek);
+EXPORT_SYMBOL(dump_skip);
+
+int dump_align(struct coredump_params *cprm, int align)
+{
+	unsigned mod = cprm->written & (align - 1);
+	if (align & (align - 1))
+		return 0;
+	return mod ? dump_skip(cprm, align - mod) : 1;
+}
+EXPORT_SYMBOL(dump_align);