Various places in fs/ext3/namei.c use ext3_next_entry to loop over directory entries, but not all of them verify that entries are valid before attempting to move to the next one. In the case where rec_len == 0 this causes an infinite loop. Introduce a new version of ext3_next_entry that checks the validity of the entry before using its data to find the next one. Rename the original function to __ext3_next_entry and use it in places where we already know the data is valid. Note that the changes to empty_dir follow the original code in reporting the directory as empty in the presence of errors. This patch fixes the first case (image hdb.25.softlockup.gz) reported in http://bugzilla.kernel.org/show_bug.cgi?id=10882. Signed-off-by: Duane Griffin <duaneg@xxxxxxxxx> -- This is version 2. The original patch was an earlier version causing warnings that I sent by mistake. This version just fixes those. Please note that I've only properly tested the originally reported failure case (i.e. the changes to ext3_dx_find_entry). Reviewers may want to pay particular attention to the changes to do_split, make_indexed_dir and empty_dir. I've tried to follow the original code's error handling conventions, as noted above for empty_dir, but I'm not sure this is the best way to do things. --- diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c index 0b8cf80..ea0236b 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -185,13 +185,27 @@ static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry, * p is at least 6 bytes before the end of page */ static inline struct ext3_dir_entry_2 * -ext3_next_entry(struct ext3_dir_entry_2 *p) +__ext3_next_entry(struct ext3_dir_entry_2 *p) { return (struct ext3_dir_entry_2 *)((char *)p + ext3_rec_len_from_disk(p->rec_len)); } /* + * Checks the directory entry looks sane before using it to find the next one. + * Returns NULL and reports an error if an invalid entry is passed. + */ +static inline struct ext3_dir_entry_2 * +ext3_next_entry(const char *func, struct inode *dir, + struct ext3_dir_entry_2 *de, struct buffer_head *bh, int offset) +{ + if (ext3_check_dir_entry(func, dir, de, bh, offset)) + return __ext3_next_entry(de); + else + return NULL; +} + +/* * Future: use high four bits of block for coalesce-on-delete flags * Mask them off for now. */ @@ -271,15 +285,17 @@ struct stats unsigned bcount; }; -static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext3_dir_entry_2 *de, - int size, int show_names) +static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct inode *dir, + struct buffer_head *bh, int size, + int show_names) { + struct ext3_dir_entry_2 *de = (struct ext3_dir_entry_2 *) bh->b_data; unsigned names = 0, space = 0; char *base = (char *) de; struct dx_hash_info h = *hinfo; printk("names: "); - while ((char *) de < base + size) + while (de && (char *) de < base + size) { if (de->inode) { @@ -295,7 +311,7 @@ static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext3_dir_ent space += EXT3_DIR_REC_LEN(de->name_len); names++; } - de = ext3_next_entry(de); + de = ext3_next_entry("dx_show_leaf", dir, de, bh, 0); } printk("(%i)\n", names); return (struct stats) { names, space, 1 }; @@ -319,7 +335,7 @@ struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir, if (!(bh = ext3_bread (NULL,dir, block, 0,&err))) continue; stats = levels? dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1): - dx_show_leaf(hinfo, (struct ext3_dir_entry_2 *) bh->b_data, blocksize, 0); + dx_show_leaf(hinfo, dir, bh, blocksize, 0); names += stats.names; space += stats.space; bcount += stats.bcount; @@ -583,7 +599,7 @@ static int htree_dirblock_to_tree(struct file *dir_file, top = (struct ext3_dir_entry_2 *) ((char *) de + dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(0)); - for (; de < top; de = ext3_next_entry(de)) { + for (; de < top; de = __ext3_next_entry(de)) { if (!ext3_check_dir_entry("htree_dirblock_to_tree", dir, de, bh, (block<<EXT3_BLOCK_SIZE_BITS(dir->i_sb)) +((char *)de - bh->b_data))) { @@ -658,7 +674,12 @@ int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash, } if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) { de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data; - de = ext3_next_entry(de); + de = ext3_next_entry("ext3_htree_fill_tree", + dir, de, frames[0].bh, 0); + if (de == NULL) { + err = -EIO; + goto errout; + } if ((err = ext3_htree_store_dirent(dir_file, 2, 0, de)) != 0) goto errout; count++; @@ -726,8 +747,7 @@ static int dx_make_map (struct ext3_dir_entry_2 *de, int size, count++; cond_resched(); } - /* XXX: do we need to check rec_len == 0 case? -Chris */ - de = ext3_next_entry(de); + de = __ext3_next_entry(de); } return count; } @@ -991,24 +1011,28 @@ static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry, de = (struct ext3_dir_entry_2 *) bh->b_data; top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize - EXT3_DIR_REC_LEN(0)); - for (; de < top; de = ext3_next_entry(de)) - if (ext3_match (namelen, name, de)) { + for (; de < top; de = __ext3_next_entry(de)) { + int offset = (block << EXT3_BLOCK_SIZE_BITS(sb)) + + ((char *) de - bh->b_data); + if (!ext3_check_dir_entry("ext3_find_entry", - dir, de, bh, - (block<<EXT3_BLOCK_SIZE_BITS(sb)) - +((char *)de - bh->b_data))) { - brelse (bh); + dir, de, bh, offset)) { + brelse(bh); *err = ERR_BAD_DX_DIR; goto errout; } - *res_dir = de; - dx_release (frames); - return bh; + + if (ext3_match(namelen, name, de)) { + *res_dir = de; + dx_release(frames); + return bh; + } } brelse (bh); + /* Check to see if we should continue to search */ - retval = ext3_htree_next_block(dir, hash, frame, - frames, NULL); + retval = ext3_htree_next_block(dir, hash, frame, frames, NULL); + if (retval < 0) { ext3_warning(sb, __func__, "error reading index page in directory #%lu", @@ -1141,7 +1165,7 @@ static struct ext3_dir_entry_2* dx_pack_dirents(char *base, int size) prev = to = de; while ((char*)de < base + size) { - next = ext3_next_entry(de); + next = __ext3_next_entry(de); if (de->inode && de->name_len) { rec_len = EXT3_DIR_REC_LEN(de->name_len); if (de > to) @@ -1172,9 +1196,22 @@ static struct ext3_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, struct dx_map_entry *map; char *data1 = (*bh)->b_data, *data2; unsigned split, move, size, i; - struct ext3_dir_entry_2 *de = NULL, *de2; + struct ext3_dir_entry_2 *de, *de2; int err = 0; + /* Verify directory entries are sane before trying anything else. */ + de = (struct ext3_dir_entry_2 *) data1; + de2 = (struct ext3_dir_entry_2 *) data1 + + dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(0); + while (de < de2) { + de = ext3_next_entry("do_split", dir, de, *bh, 0); + if (de == NULL) { + brelse(*bh); + *bh = NULL; + goto errout; + } + } + bh2 = ext3_append (handle, dir, &newblock, &err); if (!(bh2)) { brelse(*bh); @@ -1397,8 +1434,15 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, memcpy (data1, de, len); de = (struct ext3_dir_entry_2 *) data1; top = data1 + len; - while ((char *)(de2 = ext3_next_entry(de)) < top) + + while (1) { + de2 = ext3_next_entry("make_indexed_dir", dir, de, bh, 0); + if (de2 == NULL || (char *) (char *) (char *) (char *) (char *) (char *) (char *) (char *) (char *) de2 >= top) { + break; + } de = de2; + } + de->rec_len = ext3_rec_len_to_disk(data1 + blocksize - (char *) de); /* Initialize the root; the dot dirents already exist */ de = (struct ext3_dir_entry_2 *) (&root->dotdot); @@ -1655,7 +1699,7 @@ static int ext3_delete_entry (handle_t *handle, } i += ext3_rec_len_from_disk(de->rec_len); pde = de; - de = ext3_next_entry(de); + de = __ext3_next_entry(de); } return -ENOENT; } @@ -1792,7 +1836,7 @@ retry: de->rec_len = ext3_rec_len_to_disk(EXT3_DIR_REC_LEN(de->name_len)); strcpy (de->name, "."); ext3_set_de_type(dir->i_sb, de, S_IFDIR); - de = ext3_next_entry(de); + de = __ext3_next_entry(de); de->inode = cpu_to_le32(dir->i_ino); de->rec_len = ext3_rec_len_to_disk(inode->i_sb->s_blocksize - EXT3_DIR_REC_LEN(1)); @@ -1825,7 +1869,7 @@ out_stop: /* * routine to check that the specified directory is empty (for rmdir) */ -static int empty_dir (struct inode * inode) +static int empty_dir(struct inode *dir, struct inode *inode) { unsigned long offset; struct buffer_head * bh; @@ -1846,8 +1890,14 @@ static int empty_dir (struct inode * inode) inode->i_ino); return 1; } + de = (struct ext3_dir_entry_2 *) bh->b_data; - de1 = ext3_next_entry(de); + de1 = ext3_next_entry("empty_dir", dir, de, bh, 0); + if (de1 == NULL) { + brelse(bh); + return 1; + } + if (le32_to_cpu(de->inode) != inode->i_ino || !le32_to_cpu(de1->inode) || strcmp (".", de->name) || @@ -1860,8 +1910,8 @@ static int empty_dir (struct inode * inode) } offset = ext3_rec_len_from_disk(de->rec_len) + ext3_rec_len_from_disk(de1->rec_len); - de = ext3_next_entry(de1); - while (offset < inode->i_size ) { + de = ext3_next_entry("empty_dir", dir, de1, bh, offset); + while (de && offset < inode->i_size) { if (!bh || (void *) de >= (void *) (bh->b_data+sb->s_blocksize)) { err = 0; @@ -1890,7 +1940,7 @@ static int empty_dir (struct inode * inode) return 0; } offset += ext3_rec_len_from_disk(de->rec_len); - de = ext3_next_entry(de); + de = __ext3_next_entry(de); } brelse (bh); return 1; @@ -2068,7 +2121,7 @@ static int ext3_rmdir (struct inode * dir, struct dentry *dentry) goto end_rmdir; retval = -ENOTEMPTY; - if (!empty_dir (inode)) + if (!empty_dir(dir, inode)) goto end_rmdir; retval = ext3_delete_entry(handle, dir, de, bh); @@ -2244,7 +2297,7 @@ retry: } #define PARENT_INO(buffer) \ - (ext3_next_entry((struct ext3_dir_entry_2 *)(buffer))->inode) + (__ext3_next_entry((struct ext3_dir_entry_2 *)(buffer))->inode) /* * Anybody can rename anything with this: the permission checks are left to the @@ -2297,7 +2350,7 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry, if (S_ISDIR(old_inode->i_mode)) { if (new_inode) { retval = -ENOTEMPTY; - if (!empty_dir (new_inode)) + if (!empty_dir(new_dir, new_inode)) goto end_rename; } retval = -EIO; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
