From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37497) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ebDao-0005Ew-SP for qemu-devel@nongnu.org; Mon, 15 Jan 2018 17:51:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ebDan-0004Se-IH for qemu-devel@nongnu.org; Mon, 15 Jan 2018 17:51:02 -0500 From: John Snow Date: Mon, 15 Jan 2018 17:50:47 -0500 Message-Id: <20180115225047.28607-1-jsnow@redhat.com> Subject: [Qemu-devel] [PATCH v2] file-posix: specify expected filetypes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org, John Snow I don't think there's a legitimate reason to open directories as if they were files. This prevents QEMU from opening and attempting to probe a directory inode, which can break in exciting ways. One of those ways is lseek on ext4/xfs, which will return 0x7fffffffffffffff as the file size instead of EISDIR. This can coax QEMU into responding with a confusing "file too big" instead of "Hey, that's not a file". See: https://bugs.launchpad.net/qemu/+bug/1739304/ Signed-off-by: John Snow --- v2: Is something like this what you had in mind, Kevin? I couldn't make the hdev/cdrom checks more specific as I'm not sure which environments expect which, but if you know I can tighten it. block/file-posix.c | 38 +++++++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 9 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 36ee89e940..fe06cdb8f8 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -417,7 +417,8 @@ static QemuOptsList raw_runtime_opts = { }; static int raw_open_common(BlockDriverState *bs, QDict *options, - int bdrv_flags, int open_flags, Error **errp) + int bdrv_flags, int open_flags, + bool device, Error **errp) { BDRVRawState *s = bs->opaque; QemuOpts *opts; @@ -556,10 +557,30 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, error_setg_errno(errp, errno, "Could not stat file"); goto fail; } - if (S_ISREG(st.st_mode)) { - s->discard_zeroes = true; - s->has_fallocate = true; + + if (!device) { + if (S_ISBLK(st.st_mode)) { + warn_report("Opening a block device as file using 'file'" + "driver is deprecated"); + } else if (S_ISCHR(st.st_mode)) { + warn_report("Opening a character device as file using the 'file'" + "driver is deprecated"); + } else if (!S_ISREG(st.st_mode)) { + error_setg(errp, "A regular file was expected by the 'file' driver," + "but something else was given"); + goto fail; + } else { + s->discard_zeroes = true; + s->has_fallocate = true; + } + } else { + if (!(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode))) { + error_setg(errp, "host_device/host_cdrom driver expects either" + "a character or block device"); + goto fail; + } } + if (S_ISBLK(st.st_mode)) { #ifdef BLKDISCARDZEROES unsigned int arg; @@ -589,7 +610,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, s->needs_alignment = true; } #endif - #ifdef CONFIG_XFS if (platform_test_xfs_fd(s->fd)) { s->is_xfs = true; @@ -611,7 +631,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags, BDRVRawState *s = bs->opaque; s->type = FTYPE_FILE; - return raw_open_common(bs, options, flags, 0, errp); + return raw_open_common(bs, options, flags, 0, false, errp); } typedef enum { @@ -2575,7 +2595,7 @@ hdev_open_Mac_error: s->type = FTYPE_FILE; - ret = raw_open_common(bs, options, flags, 0, &local_err); + ret = raw_open_common(bs, options, flags, 0, true, &local_err); if (ret < 0) { error_propagate(errp, local_err); #if defined(__APPLE__) && defined(__MACH__) @@ -2802,7 +2822,7 @@ static int cdrom_open(BlockDriverState *bs, QDict *options, int flags, s->type = FTYPE_CD; /* open will not fail even if no CD is inserted, so add O_NONBLOCK */ - return raw_open_common(bs, options, flags, O_NONBLOCK, errp); + return raw_open_common(bs, options, flags, O_NONBLOCK, true, errp); } static int cdrom_probe_device(const char *filename) @@ -2915,7 +2935,7 @@ static int cdrom_open(BlockDriverState *bs, QDict *options, int flags, s->type = FTYPE_CD; - ret = raw_open_common(bs, options, flags, 0, &local_err); + ret = raw_open_common(bs, options, flags, 0, true, &local_err); if (ret) { error_propagate(errp, local_err); return ret; -- 2.14.3