This is a note to let you know that I've just added the patch titled
capabilities: fix potential memleak on error path from vfs_getxattr_alloc()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
capabilities-fix-potential-memleak-on-error-path-from-vfs_getxattr_alloc.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8cf0a1bc12870d148ae830a4ba88cfdf0e879cee Mon Sep 17 00:00:00 2001
From: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
Date: Tue, 25 Oct 2022 21:33:57 +0800
Subject: capabilities: fix potential memleak on error path from vfs_getxattr_alloc()
From: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
Signed-off-by: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
[PM: subject line and backtrace tweaks]
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/commoncap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -397,8 +397,10 @@ int cap_inode_getsecurity(struct inode *
&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;
Patches currently in stable-queue which might be from cuigaosheng1@xxxxxxxxxx are
queue-4.19/capabilities-fix-potential-memleak-on-error-path-from-vfs_getxattr_alloc.patch
queue-4.19/net-mdio-fix-undefined-behavior-in-bit-shift-for-__m.patch
