From patchwork Thu Dec 13 22:04:22 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [4/8] lib/ext2fs/block.c: Fix undefined behavior in block_iterate_tind() Date: Thu, 13 Dec 2012 12:04:22 -0000 From: Sami Liedes X-Patchwork-Id: 206262 Message-Id: <20121213220422.GL9713@sli.dy.fi> To: linux-ext4@vger.kernel.org The intermediate result of limit*limit*limit is too big to fit in a 32-bit integer, causing undefined behavior. Fix by casting one of the limits to the result type of e2_blkcnt_t. Caught using clang -fsanitize=undefined. Signed-off-by: Sami Liedes --- lib/ext2fs/block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/ext2fs/block.c b/lib/ext2fs/block.c index 68dcb03..dd3911d 100644 --- a/lib/ext2fs/block.c +++ b/lib/ext2fs/block.c @@ -251,7 +251,7 @@ static int block_iterate_tind(blk_t *tind_block, blk_t ref_block, } check_for_ro_violation_return(ctx, ret); if (!*tind_block || (ret & BLOCK_ABORT)) { - ctx->bcount += limit*limit*limit; + ctx->bcount += ((e2_blkcnt_t)limit)*limit*limit; return ret; } if (*tind_block >= ext2fs_blocks_count(ctx->fs->super) ||