From 9c580285c32d1e8f684c51cdc3a023319f05b1f8 Mon Sep 17 00:00:00 2001
From: mohit84 <moagrawa@redhat.com>
Date: Wed, 25 Oct 2023 11:48:51 +0530
Subject: [PATCH] dht: fix asan use-after-free bug (#4248)

The client is throwing below stacktrace while asan is enabled. The client is facing
an issue while application is trying to call removexattr in 2x1 subvol and non-mds
subvol is down. As we can see in below stacktrace dht_setxattr_mds_cbk is calling
dht_setxattr_non_mds_cbk and dht_setxattr_non_mds_cbk is trying to wipe local because
call_cnt is 0 but dht_setxattr_mds_cbk is trying to access frame->local that;s why
it is crashed.

x621000051c34 is located 1844 bytes inside of 4164-byte region [0x621000051500,0x621000052544) freed by thread T7 here:

Solution: Use switch instead of using if statement to wind a operation, in case of switch
          the code will not try to access local after wind a operation for last dht subvol.

> Fixes: #3732
> Change-Id: I031bc814d6df98058430ef4de7040e3370d1c677
> (Cherry picke from commit 11ff6f56a1e7ad740ffe46e39a5911c9e7367eb6)
> (Reviwed on upstream link https://github.com/gluster/glusterfs/pull/4242)

Fixes: #3732
Change-Id: I031bc814d6df98058430ef4de7040e3370d1c677

Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>
---
 xlators/cluster/dht/src/dht-common.c | 45 ++++++++++++++--------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index b31b88296b..c5c83c20aa 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -3965,28 +3965,29 @@ dht_setxattr_mds_cbk(call_frame_t *frame, void *cookie, xlator_t *this,
     for (i = 0; i < conf->subvolume_cnt; i++) {
         if (mds_subvol && (mds_subvol == conf->subvolumes[i]))
             continue;
-        if (local->fop == GF_FOP_SETXATTR) {
-            STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
-                       conf->subvolumes[i]->fops->setxattr, &local->loc,
-                       local->xattr, local->flags, local->xattr_req);
-        }
-
-        if (local->fop == GF_FOP_FSETXATTR) {
-            STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
-                       conf->subvolumes[i]->fops->fsetxattr, local->fd,
-                       local->xattr, local->flags, local->xattr_req);
-        }
-
-        if (local->fop == GF_FOP_REMOVEXATTR) {
-            STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
-                       conf->subvolumes[i]->fops->removexattr, &local->loc,
-                       local->key, local->xattr_req);
-        }
-
-        if (local->fop == GF_FOP_FREMOVEXATTR) {
-            STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
-                       conf->subvolumes[i]->fops->fremovexattr, local->fd,
-                       local->key, local->xattr_req);
+        switch (local->fop) {
+            case GF_FOP_SETXATTR:
+                STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
+                           conf->subvolumes[i]->fops->setxattr, &local->loc,
+                           local->xattr, local->flags, local->xattr_req);
+                break;
+            case GF_FOP_FSETXATTR:
+                STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
+                           conf->subvolumes[i]->fops->fsetxattr, local->fd,
+                           local->xattr, local->flags, local->xattr_req);
+                break;
+            case GF_FOP_REMOVEXATTR:
+                STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
+                           conf->subvolumes[i]->fops->removexattr, &local->loc,
+                           local->key, local->xattr_req);
+                break;
+            case GF_FOP_FREMOVEXATTR:
+                STACK_WIND(frame, dht_setxattr_non_mds_cbk, conf->subvolumes[i],
+                           conf->subvolumes[i]->fops->fremovexattr, local->fd,
+                           local->key, local->xattr_req);
+                break;
+            default:
+                break;
         }
     }
 
-- 
2.33.0

