diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2023-04-03 11:51:47 +0300 |
|---|---|---|
| committer | Amir Goldstein <amir73il@gmail.com> | 2023-06-19 14:01:13 +0300 |
| commit | 5522c9c7cbd2ab4e886fa1c70896f0bdd483ce0b (patch) | |
| tree | 6b93018913ace4c4d3c1d49768c4a3b4d72fe315 /fs/overlayfs/super.c | |
| parent | a6ff2bc0be179eea72832b5396481a08ccd22d5a (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/super.c')
| -rw-r--r-- | fs/overlayfs/super.c | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index ea34edd9d624..baa970a2b398 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -56,10 +56,11 @@ MODULE_PARM_DESC(xino_auto, static void ovl_entry_stack_free(struct ovl_entry *oe) { + struct ovl_path *lowerstack = ovl_lowerstack(oe); unsigned int i; - for (i = 0; i < oe->numlower; i++) - dput(oe->lowerstack[i].dentry); + for (i = 0; i < ovl_numlower(oe); i++) + dput(lowerstack[i].dentry); } static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); @@ -139,6 +140,7 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry, unsigned int flags, bool weak) { struct ovl_entry *oe = OVL_E(dentry); + struct ovl_path *lowerstack = ovl_lowerstack(oe); struct inode *inode = d_inode_rcu(dentry); struct dentry *upper; unsigned int i; @@ -152,10 +154,9 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry, if (upper) ret = ovl_revalidate_real(upper, flags, weak); - for (i = 0; ret > 0 && i < oe->numlower; i++) { - ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, - weak); - } + for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) + ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); + return ret; } @@ -1454,7 +1455,7 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, /* Verify lower root is upper root origin */ err = ovl_verify_origin(ofs, upperpath->dentry, - oe->lowerstack[0].dentry, true); + ovl_lowerstack(oe)->dentry, true); if (err) { pr_err("failed to verify upper root origin\n"); goto out; @@ -1717,6 +1718,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, { int err; struct path *stack = NULL; + struct ovl_path *lowerstack; unsigned int i; struct ovl_entry *oe; @@ -1754,9 +1756,10 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, if (!oe) goto out_err; + lowerstack = ovl_lowerstack(oe); for (i = 0; i < numlower; i++) { - oe->lowerstack[i].dentry = dget(stack[i].dentry); - oe->lowerstack[i].layer = &ofs->layers[i+1]; + lowerstack[i].dentry = dget(stack[i].dentry); + lowerstack[i].layer = &ofs->layers[i+1]; } out: @@ -1849,7 +1852,7 @@ static struct dentry *ovl_get_root(struct super_block *sb, struct ovl_entry *oe) { struct dentry *root; - struct ovl_path *lowerpath = &oe->lowerstack[0]; + struct ovl_path *lowerpath = ovl_lowerstack(oe); unsigned long ino = d_inode(lowerpath->dentry)->i_ino; int fsid = lowerpath->layer->fsid; struct ovl_inode_params oip = { |