### [CVE-2024-50265](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-50265)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=2.6.34%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=399ff3a748cf4c8c853e96dd477153202636527b%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()Syzkaller is able to provoke null-ptr-dereference in ocfs2_xa_remove():[   57.319872] (a.out,1161,7):ocfs2_xa_remove:2028 ERROR: status = -12[   57.320420] (a.out,1161,7):ocfs2_xa_cleanup_value_truncate:1999 ERROR: Partial truncate while removing xattr overlay.upper.  Leaking 1 clusters and removing the entry[   57.321727] BUG: kernel NULL pointer dereference, address: 0000000000000004[...][   57.325727] RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x2a/0xc0[...][   57.331328] Call Trace:[   57.331477]  <TASK>[...][   57.333511]  ? do_user_addr_fault+0x3e5/0x740[   57.333778]  ? exc_page_fault+0x70/0x170[   57.334016]  ? asm_exc_page_fault+0x2b/0x30[   57.334263]  ? __pfx_ocfs2_xa_block_wipe_namevalue+0x10/0x10[   57.334596]  ? ocfs2_xa_block_wipe_namevalue+0x2a/0xc0[   57.334913]  ocfs2_xa_remove_entry+0x23/0xc0[   57.335164]  ocfs2_xa_set+0x704/0xcf0[   57.335381]  ? _raw_spin_unlock+0x1a/0x40[   57.335620]  ? ocfs2_inode_cache_unlock+0x16/0x20[   57.335915]  ? trace_preempt_on+0x1e/0x70[   57.336153]  ? start_this_handle+0x16c/0x500[   57.336410]  ? preempt_count_sub+0x50/0x80[   57.336656]  ? _raw_read_unlock+0x20/0x40[   57.336906]  ? start_this_handle+0x16c/0x500[   57.337162]  ocfs2_xattr_block_set+0xa6/0x1e0[   57.337424]  __ocfs2_xattr_set_handle+0x1fd/0x5d0[   57.337706]  ? ocfs2_start_trans+0x13d/0x290[   57.337971]  ocfs2_xattr_set+0xb13/0xfb0[   57.338207]  ? dput+0x46/0x1c0[   57.338393]  ocfs2_xattr_trusted_set+0x28/0x30[   57.338665]  ? ocfs2_xattr_trusted_set+0x28/0x30[   57.338948]  __vfs_removexattr+0x92/0xc0[   57.339182]  __vfs_removexattr_locked+0xd5/0x190[   57.339456]  ? preempt_count_sub+0x50/0x80[   57.339705]  vfs_removexattr+0x5f/0x100[...]Reproducer uses faultinject facility to fail ocfs2_xa_remove() ->ocfs2_xa_value_truncate() with -ENOMEM.In this case the comment mentions that we can return 0 ifocfs2_xa_cleanup_value_truncate() is going to wipe the entryanyway. But the following 'rc' check is wrong and execution flow do'ocfs2_xa_remove_entry(loc);' twice:* 1st: in ocfs2_xa_cleanup_value_truncate();* 2nd: returning back to ocfs2_xa_remove() instead of going to 'out'.Fix this by skipping the 2nd removal of the same entry and makingsyzkaller repro happy.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/w4zu/Debian_security