6.15-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neil@brown.name
[ Upstream commit dd862da61e91123ca745e06c03ba39ce71a929d9 ]
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: 8376583b84a1 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/nfs4proc.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index b1d2122bd5a74..4b123bca65e12 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -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, - 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);
- if (status) - return ERR_PTR(status); + if (*statusp) + return NULL;
spin_lock(&dir->i_lock); /* 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, NFS_INO_INVALID_DATA); 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) @@ -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, struct iattr *sattr, - struct nfs4_label *label) + struct nfs4_label *label, int *statusp) { 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); if (data == NULL) goto out;
data->arg.label = label; - ret = nfs4_do_mkdir(dir, dentry, data); + ret = nfs4_do_mkdir(dir, dentry, data, statusp);
nfs4_free_createdata(data); 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)) sattr->ia_mode &= ~current_umask(); do { - alias = _nfs4_proc_mkdir(dir, dentry, sattr, label); - err = PTR_ERR_OR_ZERO(alias); + alias = _nfs4_proc_mkdir(dir, dentry, sattr, label, &err); trace_nfs4_mkdir(dir, &dentry->d_name, err); - err = nfs4_handle_exception(NFS_SERVER(dir), err, - &exception); + if (err) + alias = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir), + err, + &exception)); } while (exception.retry); nfs4_label_release_security(label);