From: Eric Biggers Date: Fri, 21 Feb 2020 04:50:37 +0000 (-0800) Subject: f2fs: fix leaking uninitialized memory in compressed clusters X-Git-Tag: v5.7-rc1~60^2~63 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7fa6d59816e7d81cfd4f854468c477c12b85c789;p=linux-block.git f2fs: fix leaking uninitialized memory in compressed clusters When the compressed data of a cluster doesn't end on a page boundary, the remainder of the last page must be zeroed in order to avoid leaking uninitialized memory to disk. Fixes: 4c8ff7095bef ("f2fs: support data compression") Signed-off-by: Eric Biggers Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index d8a64be90a50..ef7dd04312fe 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -385,11 +385,15 @@ static int f2fs_compress_pages(struct compress_ctx *cc) for (i = 0; i < COMPRESS_DATA_RESERVED_SIZE; i++) cc->cbuf->reserved[i] = cpu_to_le32(0); + nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE); + + /* zero out any unused part of the last page */ + memset(&cc->cbuf->cdata[cc->clen], 0, + (nr_cpages * PAGE_SIZE) - (cc->clen + COMPRESS_HEADER_SIZE)); + vunmap(cc->cbuf); vunmap(cc->rbuf); - nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE); - for (i = nr_cpages; i < cc->nr_cpages; i++) { f2fs_put_compressed_page(cc->cpages[i]); cc->cpages[i] = NULL;