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authorAmir Goldstein <amir73il@gmail.com>2023-04-03 11:51:47 +0300
committerAmir Goldstein <amir73il@gmail.com>2023-06-19 14:01:13 +0300
commit5522c9c7cbd2ab4e886fa1c70896f0bdd483ce0b (patch)
tree6b93018913ace4c4d3c1d49768c4a3b4d72fe315 /fs/overlayfs/export.c
parenta6ff2bc0be179eea72832b5396481a08ccd22d5a (diff)
ovl: use ovl_numlower() and ovl_lowerstack() accessors
This helps fortify against dereferencing a NULL ovl_entry, before we move the ovl_entry reference into ovl_inode. Reviewed-by: Alexander Larsson <alexl@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/export.c')
-rw-r--r--fs/overlayfs/export.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 2cfdfcca5659..ddb546627749 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -80,7 +80,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
/* We can get overlay root from root of any layer */
if (dentry == dentry->d_sb->s_root)
- return oe->numlower;
+ return ovl_numlower(oe);
/*
* If it's an unindexed merge dir, then it's not connectable with any
@@ -91,7 +91,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
return 0;
/* We can get upper/overlay path from indexed/lower dentry */
- return oe->lowerstack[0].layer->idx;
+ return ovl_lowerstack(oe)->layer->idx;
}
/*
@@ -105,6 +105,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
static int ovl_connect_layer(struct dentry *dentry)
{
struct dentry *next, *parent = NULL;
+ struct ovl_entry *oe = OVL_E(dentry);
int origin_layer;
int err = 0;
@@ -112,7 +113,7 @@ static int ovl_connect_layer(struct dentry *dentry)
WARN_ON(!ovl_dentry_lower(dentry)))
return -EIO;
- origin_layer = OVL_E(dentry)->lowerstack[0].layer->idx;
+ origin_layer = ovl_lowerstack(oe)->layer->idx;
if (ovl_dentry_test_flag(OVL_E_CONNECTED, dentry))
return origin_layer;
@@ -319,8 +320,8 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
goto nomem;
if (lower) {
- oe->lowerstack->dentry = dget(lower);
- oe->lowerstack->layer = lowerpath->layer;
+ ovl_lowerstack(oe)->dentry = dget(lower);
+ ovl_lowerstack(oe)->layer = lowerpath->layer;
}
dentry->d_fsdata = oe;
if (upper_alias)
@@ -342,14 +343,15 @@ out_iput:
static struct dentry *ovl_dentry_real_at(struct dentry *dentry, int idx)
{
struct ovl_entry *oe = OVL_E(dentry);
+ struct ovl_path *lowerstack = ovl_lowerstack(oe);
int i;
if (!idx)
return ovl_dentry_upper(dentry);
- for (i = 0; i < oe->numlower; i++) {
- if (oe->lowerstack[i].layer->idx == idx)
- return oe->lowerstack[i].dentry;
+ for (i = 0; i < ovl_numlower(oe); i++) {
+ if (lowerstack[i].layer->idx == idx)
+ return lowerstack[i].dentry;
}
return NULL;