>From stable-bounces@linux.kernel.org Sun Jul 30 03:04:26 2006 Message-Id: <200607301003.k6UA31hC002485@shell0.pdx.osdl.net> To: torvalds@osdl.org From: akpm@osdl.org Date: Sun, 30 Jul 2006 03:03:01 -0700 Cc: akpm@osdl.org, jack@suse.cz, esandeen@redhat.com, neilb@suse.de, sct@redhat.com, marcel@holtmann.org, stable@kernel.org Subject: ext3: avoid triggering ext3_error on bad NFS file handle From: Neil Brown The inode number out of an NFS file handle gets passed eventually to ext3_get_inode_block() without any checking. If ext3_get_inode_block() allows it to trigger an error, then bad filehandles can have unpleasant effect - ext3_error() will usually cause a forced read-only remount, or a panic if `errors=panic' was used. So remove the call to ext3_error there and put a matching check in ext3/namei.c where inode numbers are read off storage. [akpm@osdl.org: fix off-by-one error] Signed-off-by: Neil Brown Signed-off-by: Jan Kara Cc: Marcel Holtmann Cc: "Stephen C. Tweedie" Cc: Eric Sandeen Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ext3/inode.c | 13 +++++++------ fs/ext3/namei.c | 15 +++++++++++++-- include/linux/ext3_fs.h | 9 +++++++++ 3 files changed, 29 insertions(+), 8 deletions(-) --- linux-2.6.17.7.orig/fs/ext3/inode.c +++ linux-2.6.17.7/fs/ext3/inode.c @@ -2402,14 +2402,15 @@ static unsigned long ext3_get_inode_bloc struct buffer_head *bh; struct ext3_group_desc * gdp; - - if ((ino != EXT3_ROOT_INO && ino != EXT3_JOURNAL_INO && - ino != EXT3_RESIZE_INO && ino < EXT3_FIRST_INO(sb)) || - ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count)) { - ext3_error(sb, "ext3_get_inode_block", - "bad inode number: %lu", ino); + if (!ext3_valid_inum(sb, ino)) { + /* + * This error is already checked for in namei.c unless we are + * looking at an NFS filehandle, in which case no error + * report is needed + */ return 0; } + block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb); if (block_group >= EXT3_SB(sb)->s_groups_count) { ext3_error(sb,"ext3_get_inode_block","group >= groups count"); --- linux-2.6.17.7.orig/fs/ext3/namei.c +++ linux-2.6.17.7/fs/ext3/namei.c @@ -1000,7 +1000,12 @@ static struct dentry *ext3_lookup(struct if (bh) { unsigned long ino = le32_to_cpu(de->inode); brelse (bh); - inode = iget(dir->i_sb, ino); + if (!ext3_valid_inum(dir->i_sb, ino)) { + ext3_error(dir->i_sb, "ext3_lookup", + "bad inode number: %lu", ino); + inode = NULL; + } else + inode = iget(dir->i_sb, ino); if (!inode) return ERR_PTR(-EACCES); @@ -1028,7 +1033,13 @@ struct dentry *ext3_get_parent(struct de return ERR_PTR(-ENOENT); ino = le32_to_cpu(de->inode); brelse(bh); - inode = iget(child->d_inode->i_sb, ino); + + if (!ext3_valid_inum(child->d_inode->i_sb, ino)) { + ext3_error(child->d_inode->i_sb, "ext3_get_parent", + "bad inode number: %lu", ino); + inode = NULL; + } else + inode = iget(child->d_inode->i_sb, ino); if (!inode) return ERR_PTR(-EACCES); --- linux-2.6.17.7.orig/include/linux/ext3_fs.h +++ linux-2.6.17.7/include/linux/ext3_fs.h @@ -495,6 +495,15 @@ static inline struct ext3_inode_info *EX { return container_of(inode, struct ext3_inode_info, vfs_inode); } + +static inline int ext3_valid_inum(struct super_block *sb, unsigned long ino) +{ + return ino == EXT3_ROOT_INO || + ino == EXT3_JOURNAL_INO || + ino == EXT3_RESIZE_INO || + (ino >= EXT3_FIRST_INO(sb) && + ino <= le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count)); +} #else /* Assume that user mode programs are passing in an ext3fs superblock, not * a kernel struct super_block. This will allow us to call the feature-test