5.4-stable review patch. If anyone has any objections, please let me know.
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From: Wang Zhaolong wangzhaolong1@huawei.com
commit e48f9d849bfdec276eebf782a84fd4dfbe1c14c0 upstream.
Multiple pointers in struct cifs_search_info (ntwrk_buf_start, srch_entries_start, and last_entry) point to the same allocated buffer. However, when freeing this buffer, only ntwrk_buf_start was set to NULL, while the other pointers remained pointing to freed memory.
This is defensive programming to prevent potential issues with stale pointers. While the active UAF vulnerability is fixed by the previous patch, this change ensures consistent pointer state and more robust error handling.
Signed-off-by: Wang Zhaolong wangzhaolong1@huawei.com Cc: stable@vger.kernel.org Reviewed-by: Paulo Alcantara (Red Hat) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Wang Zhaolong wangzhaolong1@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/readdir.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -621,7 +621,10 @@ find_cifs_entry(const unsigned int xid, else cifs_buf_release(cfile->srch_inf. ntwrk_buf_start); + /* Reset all pointers to the network buffer to prevent stale references */ cfile->srch_inf.ntwrk_buf_start = NULL; + cfile->srch_inf.srch_entries_start = NULL; + cfile->srch_inf.last_entry = NULL; } rc = initiate_cifs_search(xid, file); if (rc) {