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[PATCH] ext3: avoid triggering ext3_error on bad NFS file handle

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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 <neilb@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: <stable@kernel.org>
Cc: "Stephen C. Tweedie" <sct@redhat.com>
Cc: Eric Sandeen <esandeen@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Neil Brown 2006-07-30 03:03:01 -07:00 committed by Linus Torvalds
parent f712c0c7e1
commit 2ccb48ebb4
3 changed files with 29 additions and 8 deletions
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13
fs/ext3/inode.c
View file

@ -2402,14 +2402,15 @@ static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
struct buffer_head *bh; struct buffer_head *bh;
struct ext3_group_desc * gdp; struct ext3_group_desc * gdp;
if (!ext3_valid_inum(sb, ino)) {
if ((ino != EXT3_ROOT_INO && ino != EXT3_JOURNAL_INO && /*
ino != EXT3_RESIZE_INO && ino < EXT3_FIRST_INO(sb)) || * This error is already checked for in namei.c unless we are
ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count)) { * looking at an NFS filehandle, in which case no error
ext3_error(sb, "ext3_get_inode_block", * report is needed
"bad inode number: %lu", ino); */
return 0; return 0;
} }
block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb); block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
if (block_group >= EXT3_SB(sb)->s_groups_count) { if (block_group >= EXT3_SB(sb)->s_groups_count) {
ext3_error(sb,"ext3_get_inode_block","group >= groups count"); ext3_error(sb,"ext3_get_inode_block","group >= groups count");

15
fs/ext3/namei.c
View file

@ -1000,7 +1000,12 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
if (bh) { if (bh) {
unsigned long ino = le32_to_cpu(de->inode); unsigned long ino = le32_to_cpu(de->inode);
brelse (bh); 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) if (!inode)
return ERR_PTR(-EACCES); return ERR_PTR(-EACCES);
@ -1028,7 +1033,13 @@ struct dentry *ext3_get_parent(struct dentry *child)
return ERR_PTR(-ENOENT); return ERR_PTR(-ENOENT);
ino = le32_to_cpu(de->inode); ino = le32_to_cpu(de->inode);
brelse(bh); 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) if (!inode)
return ERR_PTR(-EACCES); return ERR_PTR(-EACCES);

9
include/linux/ext3_fs.h
View file

@ -492,6 +492,15 @@ static inline struct ext3_inode_info *EXT3_I(struct inode *inode)
{ {
return container_of(inode, struct ext3_inode_info, vfs_inode); 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 #else
/* Assume that user mode programs are passing in an ext3fs superblock, not /* 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 * a kernel struct super_block. This will allow us to call the feature-test