From: Or Ozeri <oro@il.ibm.com>
Date: Thu, 24 Dec 2020 09:24:40 +0000 (+0200)
Subject: librbd: fix crypto handling of empty reads
X-Git-Tag: v16.1.0~87^2~10
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=867d5c962d92d6b40f67b6e55c3ccff0e1183ed6;p=ceph.git

librbd: fix crypto handling of empty reads

This commit ensures correct handling of empty bufferlists returned by librados object read

Signed-off-by: Or Ozeri <oro@il.ibm.com>
---

diff --git a/src/librbd/crypto/CryptoInterface.h b/src/librbd/crypto/CryptoInterface.h
index 29e205188fe8..8b1f57924b1f 100644
--- a/src/librbd/crypto/CryptoInterface.h
+++ b/src/librbd/crypto/CryptoInterface.h
@@ -60,7 +60,7 @@ public:
 
   inline int decrypt_aligned_extent(io::ReadExtent& extent,
                                     uint64_t image_offset) {
-    if (extent.length == 0) {
+    if (extent.length == 0 || extent.bl.length() == 0) {
       return 0;
     }
 
diff --git a/src/librbd/crypto/CryptoObjectDispatch.cc b/src/librbd/crypto/CryptoObjectDispatch.cc
index b82cd679f764..2c5f9b37019b 100644
--- a/src/librbd/crypto/CryptoObjectDispatch.cc
+++ b/src/librbd/crypto/CryptoObjectDispatch.cc
@@ -132,8 +132,13 @@ struct C_UnalignedObjectReadRequest : public Context {
         auto& extent = (*extents)[i];
         auto& aligned_extent = aligned_extents[i];
         if (aligned_extent.extent_map.empty()) {
-          aligned_extent.bl.splice(extent.offset - aligned_extent.offset,
-                                   extent.length, &extent.bl);
+          uint64_t cut_offset = extent.offset - aligned_extent.offset;
+          int64_t padding_count =
+                  cut_offset + extent.length - aligned_extent.bl.length();
+          if (padding_count > 0) {
+            aligned_extent.bl.append_zero(padding_count);
+          }
+          aligned_extent.bl.splice(cut_offset, extent.length, &extent.bl);
         } else {
           for (auto [off, len]: aligned_extent.extent_map) {
             ceph::bufferlist tmp;