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nfs: fix incorrect handling of large-number NFS errors in nfs4_do_mkdir()

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A recent commit introduced nfs4_do_mkdir() which reports an error from
nfs4_call_sync() by returning it with ERR_PTR().

This is a problem as nfs4_call_sync() can return negative NFS-specific
errors with values larger than MAX_ERRNO (4095).  One example is
NFS4ERR_DELAY which has value 10008.

This "pointer" gets to PTR_ERR_OR_ZERO() in nfs4_proc_mkdir() which
chooses ZERO because it isn't in the range of value errors.  Ultimately
the pointer is dereferenced.

This patch changes nfs4_do_mkdir() to report the dentry pointer and
status separately - pointer as a return value, status in an "int *"
parameter.

The same separation is used for _nfs4_proc_mkdir() and the two are
combined only in nfs4_proc_mkdir() after the status has passed through
nfs4_handle_exception(), which ensures the error code does not exceed
MAX_ERRNO.

It also fixes a problem in the even when nfs4_handle_exception() updated
the error value, the original 'alias' was still returned.

Reported-by: Anna Schumaker <anna@kernel.org>
Fixes: 8376583b84 ("nfs: change mkdir inode_operation to return alternate dentry if needed.")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
This commit is contained in:
NeilBrown 2025-05-26 14:08:25 +10:00 committed by Anna Schumaker
parent 80c4de6ab4
commit dd862da61e
1 changed files with 20 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
fs/nfs/nfs4proc.c
View File

@ -5164,13 +5164,15 @@ static int nfs4_do_create(struct inode *dir, struct dentry *dentry, struct nfs4_
} }
static struct dentry *nfs4_do_mkdir(struct inode *dir, struct dentry *dentry, static struct dentry *nfs4_do_mkdir(struct inode *dir, struct dentry *dentry,
struct nfs4_createdata *data) struct nfs4_createdata *data, int *statusp)
{ {
int status = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &data->msg, struct dentry *ret;
*statusp = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &data->msg,
&data->arg.seq_args, &data->res.seq_res, 1); &data->arg.seq_args, &data->res.seq_res, 1);
if (status) if (*statusp)
return ERR_PTR(status); return NULL;
spin_lock(&dir->i_lock); spin_lock(&dir->i_lock);
/* Creating a directory bumps nlink in the parent */ /* Creating a directory bumps nlink in the parent */
@ -5179,7 +5181,11 @@ static struct dentry *nfs4_do_mkdir(struct inode *dir, struct dentry *dentry,
data->res.fattr->time_start, data->res.fattr->time_start,
NFS_INO_INVALID_DATA); NFS_INO_INVALID_DATA);
spin_unlock(&dir->i_lock); spin_unlock(&dir->i_lock);
return nfs_add_or_obtain(dentry, data->res.fh, data->res.fattr); ret = nfs_add_or_obtain(dentry, data->res.fh, data->res.fattr);
if (!IS_ERR(ret))
return ret;
*statusp = PTR_ERR(ret);
return NULL;
} }
static void nfs4_free_createdata(struct nfs4_createdata *data) static void nfs4_free_createdata(struct nfs4_createdata *data)
@ -5240,17 +5246,18 @@ static int nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
static struct dentry *_nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry, static struct dentry *_nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
struct iattr *sattr, struct iattr *sattr,
struct nfs4_label *label) struct nfs4_label *label, int *statusp)
{ {
struct nfs4_createdata *data; struct nfs4_createdata *data;
struct dentry *ret = ERR_PTR(-ENOMEM); struct dentry *ret = NULL;
*statusp = -ENOMEM;
data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4DIR); data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4DIR);
if (data == NULL) if (data == NULL)
goto out; goto out;
data->arg.label = label; data->arg.label = label;
ret = nfs4_do_mkdir(dir, dentry, data); ret = nfs4_do_mkdir(dir, dentry, data, statusp);
nfs4_free_createdata(data); nfs4_free_createdata(data);
out: out:
@ -5273,11 +5280,12 @@ static struct dentry *nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK)) if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
sattr->ia_mode &= ~current_umask(); sattr->ia_mode &= ~current_umask();
do { do {
alias = _nfs4_proc_mkdir(dir, dentry, sattr, label); alias = _nfs4_proc_mkdir(dir, dentry, sattr, label, &err);
err = PTR_ERR_OR_ZERO(alias);
trace_nfs4_mkdir(dir, &dentry->d_name, err); trace_nfs4_mkdir(dir, &dentry->d_name, err);
err = nfs4_handle_exception(NFS_SERVER(dir), err, if (err)
&exception); alias = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
err,
&exception));
} while (exception.retry); } while (exception.retry);
nfs4_label_release_security(label); nfs4_label_release_security(label);