From 2de8eec8afb75792440b8900a01d52b8f6742fd1 Mon Sep 17 00:00:00 2001 From: Gaosheng Cui Date: Tue, 25 Oct 2022 21:33:57 +0800 Subject: [PATCH] capabilities: fix potential memleak on error path from vfs_getxattr_alloc() commit 8cf0a1bc12870d148ae830a4ba88cfdf0e879cee upstream. In cap_inode_getsecurity(), we will use vfs_getxattr_alloc() to complete the memory allocation of tmpbuf, if we have completed the memory allocation of tmpbuf, but failed to call handler->get(...), there will be a memleak in below logic: |-- ret = (int)vfs_getxattr_alloc(mnt_userns, ...) | /* ^^^ alloc for tmpbuf */ |-- value = krealloc(*xattr_value, error + 1, flags) | /* ^^^ alloc memory */ |-- error = handler->get(handler, ...) | /* error! */ |-- *xattr_value = value | /* xattr_value is &tmpbuf (memory leak!) */ So we will try to free(tmpbuf) after vfs_getxattr_alloc() fails to fix it. Cc: stable@vger.kernel.org Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities") Signed-off-by: Gaosheng Cui Acked-by: Serge Hallyn [PM: subject line and backtrace tweaks] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- security/commoncap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index 5fc8986c3c77..bc751fa5adad 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -401,8 +401,10 @@ int cap_inode_getsecurity(struct user_namespace *mnt_userns, &tmpbuf, size, GFP_NOFS); dput(dentry); - if (ret < 0 || !tmpbuf) - return ret; + if (ret < 0 || !tmpbuf) { + size = ret; + goto out_free; + } fs_ns = inode->i_sb->s_user_ns; cap = (struct vfs_cap_data *) tmpbuf;