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 (cherry picked from commit e48f9d849bfdec276eebf782a84fd4dfbe1c14c0) --- fs/cifs/readdir.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c index de6077ab7cd6..6aa3c267f4ca 100644 --- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -760,11 +760,14 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos, cifs_small_buf_release(cfile->srch_inf. ntwrk_buf_start); 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, full_path); if (rc) { cifs_dbg(FYI, "error %d reinitiating a search on rewind\n", rc);