From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: [PATCH 05/25] libext2fs: don't overflow when punching indirect blocks with large blocks Date: Thu, 17 Oct 2013 21:49:28 -0700 Message-ID: <20131018044928.7339.30260.stgit@birch.djwong.org> References: <20131018044854.7339.48457.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu, darrick.wong@oracle.com Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:30468 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751059Ab3JREtd (ORCPT ); Fri, 18 Oct 2013 00:49:33 -0400 In-Reply-To: <20131018044854.7339.48457.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On a FS with a rather large blockize (> 4K), the old block map structure can construct a fat enough "tree" (or whatever we call that lopsided thing) that (at least in theory) one could create mappings for logical blocks higher than 32 bits. In practice this doesn't happen, but the 'max' and 'iter' variables that the punch helpers use will overflow because the BLOCK_SIZE_BITS shifts are too large to fit a 32-bit variable. This causes punch to fail on TIND-mapped blocks even if the file is < 16T. So enlarge the fields to fit. (Yes this is an obscure corner case...) Signed-off-by: Darrick J. Wong --- lib/ext2fs/punch.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c index 4471f46..790a0ad8 100644 --- a/lib/ext2fs/punch.c +++ b/lib/ext2fs/punch.c @@ -50,15 +50,16 @@ static errcode_t ind_punch(ext2_filsys fs, struct ext2_inode *inode, blk_t start, blk_t count, int max) { errcode_t retval; - blk_t b, offset; - int i, incr; + blk_t b; + int i; + blk64_t offset, incr; int freed = 0; #ifdef PUNCH_DEBUG printf("Entering ind_punch, level %d, start %u, count %u, " "max %d\n", level, start, count, max); #endif - incr = 1 << ((EXT2_BLOCK_SIZE_BITS(fs->super)-2)*level); + incr = 1ULL << ((EXT2_BLOCK_SIZE_BITS(fs->super)-2)*level); for (i=0, offset=0; i < max; i++, p++, offset += incr) { if (offset >= start + count) break; @@ -87,7 +88,7 @@ static errcode_t ind_punch(ext2_filsys fs, struct ext2_inode *inode, continue; } #ifdef PUNCH_DEBUG - printf("Freeing block %u (offset %d)\n", b, offset); + printf("Freeing block %u (offset %llu)\n", b, offset); #endif ext2fs_block_alloc_stats(fs, b, -1); *p = 0; @@ -108,7 +109,7 @@ static errcode_t ext2fs_punch_ind(ext2_filsys fs, struct ext2_inode *inode, int num = EXT2_NDIR_BLOCKS; blk_t *bp = inode->i_block; blk_t addr_per_block; - blk_t max = EXT2_NDIR_BLOCKS; + blk64_t max = EXT2_NDIR_BLOCKS; if (!block_buf) { retval = ext2fs_get_array(3, fs->blocksize, &buf); @@ -119,10 +120,10 @@ static errcode_t ext2fs_punch_ind(ext2_filsys fs, struct ext2_inode *inode, addr_per_block = (blk_t) fs->blocksize >> 2; - for (level=0; level < 4; level++, max *= addr_per_block) { + for (level = 0; level < 4; level++, max *= (blk64_t)addr_per_block) { #ifdef PUNCH_DEBUG printf("Main loop level %d, start %u count %u " - "max %d num %d\n", level, start, count, max, num); + "max %llu num %d\n", level, start, count, max, num); #endif if (start < max) { retval = ind_punch(fs, inode, block_buf, bp, level,