Date: Mon, 28 Jan 2019 02:12:48 +0000 (UTC) From: "Pedro F. Giffuni" <pfg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r343517 - stable/11/sys/fs/ext2fs Message-ID: <201901280212.x0S2CmJ2016740@repo.freebsd.org>
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Author: pfg Date: Mon Jan 28 02:12:48 2019 New Revision: 343517 URL: https://svnweb.freebsd.org/changeset/base/343517 Log: MFC r343459: (parcial) ext2fs: Add some extra consistency checks for the superblock. Maliciously formed, or badly corrupted, filesystems can cause kernel panics. In general, such acts of foot-shooting can only be accomplished by root, but in a world with VM images that is moving towards automated mounts it is important to have some form of prevention. Reported by: Christopher Krah, Thomas Barabosch, and Jan-Niclas Hilgert of Fraunhofer FKIE. Incidentaly this should also fix a memory corruption issue reported by Dr Silvio Cesare of InfoSect. Huge thanks to all reseachers for making us aware of the issue. Note: for the MFC to stable/11 several changes had to made. admbug: 872, 891 Reviewed by: fsu Obtained from: NetBSD (with changes) Modified: stable/11/sys/fs/ext2fs/ext2_vfsops.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/fs/ext2fs/ext2_vfsops.c ============================================================================== --- stable/11/sys/fs/ext2fs/ext2_vfsops.c Mon Jan 28 02:00:39 2019 (r343516) +++ stable/11/sys/fs/ext2fs/ext2_vfsops.c Mon Jan 28 02:12:48 2019 (r343517) @@ -369,8 +369,27 @@ compute_sb_data(struct vnode *devvp, struct ext2fs *es es->e3fs_desc_size); return (EINVAL); } + /* Check for block size = 1K|2K|4K */ + if (es->e2fs_log_bsize > 2) { + printf("ext2fs: bad block size: %d\n", es->e2fs_log_bsize); + return (EINVAL); + } + /* Check for group size */ + if (fs->e2fs_bpg == 0) { + printf("ext2fs: zero blocks per group\n"); + return (EINVAL); + } + if (fs->e2fs_bpg != fs->e2fs_bsize * 8) { + printf("ext2fs: non-standard group size unsupported %d\n", + fs->e2fs_bpg); + return (EINVAL); + } fs->e2fs_ipb = fs->e2fs_bsize / EXT2_INODE_SIZE(fs); + if (fs->e2fs_ipg == 0) { + printf("ext2fs: zero inodes per group\n"); + return (EINVAL); + } fs->e2fs_itpg = fs->e2fs_ipg / fs->e2fs_ipb; /* s_resuid / s_resgid ? */ fs->e2fs_gcount = howmany(es->e2fs_bcount - es->e2fs_first_dblock,
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