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![Christoph Hellwig](/assets/img/avatar_default.png)
Fix the callback jffs2 passes to read_cache_page to actually have the proper type expected. Casting around function pointers can easily hide typing bugs, and defeats control flow protection. Link: http://lkml.kernel.org/r/20190520055731.24538-4-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
332 lines
9.1 KiB
C
332 lines
9.1 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2001-2007 Red Hat, Inc.
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* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/time.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/crc32.h>
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#include <linux/jffs2.h>
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#include "nodelist.h"
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static int jffs2_write_end(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *pg, void *fsdata);
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static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata);
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static int jffs2_readpage (struct file *filp, struct page *pg);
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int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
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{
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struct inode *inode = filp->f_mapping->host;
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struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
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int ret;
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ret = file_write_and_wait_range(filp, start, end);
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if (ret)
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return ret;
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inode_lock(inode);
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/* Trigger GC to flush any pending writes for this inode */
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jffs2_flush_wbuf_gc(c, inode->i_ino);
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inode_unlock(inode);
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return 0;
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}
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const struct file_operations jffs2_file_operations =
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{
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.llseek = generic_file_llseek,
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.open = generic_file_open,
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.unlocked_ioctl=jffs2_ioctl,
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.mmap = generic_file_readonly_mmap,
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.fsync = jffs2_fsync,
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.splice_read = generic_file_splice_read,
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};
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/* jffs2_file_inode_operations */
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const struct inode_operations jffs2_file_inode_operations =
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{
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.get_acl = jffs2_get_acl,
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.set_acl = jffs2_set_acl,
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.setattr = jffs2_setattr,
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.listxattr = jffs2_listxattr,
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};
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const struct address_space_operations jffs2_file_address_operations =
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{
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.readpage = jffs2_readpage,
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.write_begin = jffs2_write_begin,
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.write_end = jffs2_write_end,
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};
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static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
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{
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struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
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struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
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unsigned char *pg_buf;
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int ret;
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jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
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__func__, inode->i_ino, pg->index << PAGE_SHIFT);
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BUG_ON(!PageLocked(pg));
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pg_buf = kmap(pg);
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/* FIXME: Can kmap fail? */
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ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
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PAGE_SIZE);
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if (ret) {
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ClearPageUptodate(pg);
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SetPageError(pg);
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} else {
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SetPageUptodate(pg);
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ClearPageError(pg);
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}
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flush_dcache_page(pg);
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kunmap(pg);
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jffs2_dbg(2, "readpage finished\n");
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return ret;
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}
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int jffs2_do_readpage_unlock(void *data, struct page *pg)
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{
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int ret = jffs2_do_readpage_nolock(data, pg);
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unlock_page(pg);
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return ret;
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}
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static int jffs2_readpage (struct file *filp, struct page *pg)
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{
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struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
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int ret;
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mutex_lock(&f->sem);
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ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
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mutex_unlock(&f->sem);
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return ret;
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}
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static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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struct page *pg;
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struct inode *inode = mapping->host;
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struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
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pgoff_t index = pos >> PAGE_SHIFT;
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uint32_t pageofs = index << PAGE_SHIFT;
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int ret = 0;
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pg = grab_cache_page_write_begin(mapping, index, flags);
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if (!pg)
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return -ENOMEM;
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*pagep = pg;
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jffs2_dbg(1, "%s()\n", __func__);
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if (pageofs > inode->i_size) {
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/* Make new hole frag from old EOF to new page */
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struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
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struct jffs2_raw_inode ri;
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struct jffs2_full_dnode *fn;
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uint32_t alloc_len;
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jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
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(unsigned int)inode->i_size, pageofs);
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ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
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ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
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if (ret)
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goto out_page;
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mutex_lock(&f->sem);
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memset(&ri, 0, sizeof(ri));
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ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
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ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
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ri.totlen = cpu_to_je32(sizeof(ri));
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ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
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ri.ino = cpu_to_je32(f->inocache->ino);
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ri.version = cpu_to_je32(++f->highest_version);
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ri.mode = cpu_to_jemode(inode->i_mode);
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ri.uid = cpu_to_je16(i_uid_read(inode));
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ri.gid = cpu_to_je16(i_gid_read(inode));
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ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
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ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
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ri.offset = cpu_to_je32(inode->i_size);
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ri.dsize = cpu_to_je32(pageofs - inode->i_size);
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ri.csize = cpu_to_je32(0);
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ri.compr = JFFS2_COMPR_ZERO;
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ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
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ri.data_crc = cpu_to_je32(0);
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fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
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if (IS_ERR(fn)) {
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ret = PTR_ERR(fn);
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jffs2_complete_reservation(c);
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mutex_unlock(&f->sem);
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goto out_page;
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}
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ret = jffs2_add_full_dnode_to_inode(c, f, fn);
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if (f->metadata) {
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jffs2_mark_node_obsolete(c, f->metadata->raw);
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jffs2_free_full_dnode(f->metadata);
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f->metadata = NULL;
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}
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if (ret) {
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jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
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ret);
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jffs2_mark_node_obsolete(c, fn->raw);
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jffs2_free_full_dnode(fn);
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jffs2_complete_reservation(c);
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mutex_unlock(&f->sem);
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goto out_page;
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}
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jffs2_complete_reservation(c);
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inode->i_size = pageofs;
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mutex_unlock(&f->sem);
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}
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/*
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* Read in the page if it wasn't already present. Cannot optimize away
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* the whole page write case until jffs2_write_end can handle the
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* case of a short-copy.
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*/
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if (!PageUptodate(pg)) {
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mutex_lock(&f->sem);
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ret = jffs2_do_readpage_nolock(inode, pg);
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mutex_unlock(&f->sem);
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if (ret)
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goto out_page;
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}
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jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
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return ret;
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out_page:
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unlock_page(pg);
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put_page(pg);
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return ret;
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}
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static int jffs2_write_end(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *pg, void *fsdata)
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{
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/* Actually commit the write from the page cache page we're looking at.
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* For now, we write the full page out each time. It sucks, but it's simple
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*/
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struct inode *inode = mapping->host;
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struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
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struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
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struct jffs2_raw_inode *ri;
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unsigned start = pos & (PAGE_SIZE - 1);
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unsigned end = start + copied;
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unsigned aligned_start = start & ~3;
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int ret = 0;
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uint32_t writtenlen = 0;
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jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
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__func__, inode->i_ino, pg->index << PAGE_SHIFT,
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start, end, pg->flags);
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/* We need to avoid deadlock with page_cache_read() in
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jffs2_garbage_collect_pass(). So the page must be
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up to date to prevent page_cache_read() from trying
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to re-lock it. */
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BUG_ON(!PageUptodate(pg));
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if (end == PAGE_SIZE) {
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/* When writing out the end of a page, write out the
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_whole_ page. This helps to reduce the number of
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nodes in files which have many short writes, like
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syslog files. */
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aligned_start = 0;
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}
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ri = jffs2_alloc_raw_inode();
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if (!ri) {
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jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
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__func__);
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unlock_page(pg);
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put_page(pg);
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return -ENOMEM;
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}
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/* Set the fields that the generic jffs2_write_inode_range() code can't find */
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ri->ino = cpu_to_je32(inode->i_ino);
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ri->mode = cpu_to_jemode(inode->i_mode);
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ri->uid = cpu_to_je16(i_uid_read(inode));
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ri->gid = cpu_to_je16(i_gid_read(inode));
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ri->isize = cpu_to_je32((uint32_t)inode->i_size);
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ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
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/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
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hurt to do it again. The alternative is ifdefs, which are ugly. */
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kmap(pg);
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ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
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(pg->index << PAGE_SHIFT) + aligned_start,
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end - aligned_start, &writtenlen);
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kunmap(pg);
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if (ret) {
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/* There was an error writing. */
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SetPageError(pg);
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}
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/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
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writtenlen -= min(writtenlen, (start - aligned_start));
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if (writtenlen) {
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if (inode->i_size < pos + writtenlen) {
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inode->i_size = pos + writtenlen;
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inode->i_blocks = (inode->i_size + 511) >> 9;
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inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
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}
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}
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jffs2_free_raw_inode(ri);
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if (start+writtenlen < end) {
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/* generic_file_write has written more to the page cache than we've
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actually written to the medium. Mark the page !Uptodate so that
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it gets reread */
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jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
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__func__);
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SetPageError(pg);
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ClearPageUptodate(pg);
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}
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jffs2_dbg(1, "%s() returning %d\n",
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__func__, writtenlen > 0 ? writtenlen : ret);
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unlock_page(pg);
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put_page(pg);
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return writtenlen > 0 ? writtenlen : ret;
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}
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