From: Junrui Luo <moonafterrain@outlook.com>
To: Trond Myklebust <trondmy@kernel.org>,
Anna Schumaker <anna@kernel.org>,
Weston Andros Adamson <dros@primarydata.com>,
Tao Peng <bergwolf@primarydata.com>,
Tom Haynes <loghyr@primarydata.com>
Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Yuhao Jiang <danisjiang@gmail.com>,
stable@vger.kernel.org, Junrui Luo <moonafterrain@outlook.com>
Subject: [PATCH] pnfs/flexfiles: reject zero version_count in GETDEVICEINFO
Date: Mon, 20 Apr 2026 21:01:47 +0800 [thread overview]
Message-ID: <SYBPR01MB78811DDDAA116611B5CA56EBAF2F2@SYBPR01MB7881.ausprd01.prod.outlook.com> (raw)
nfs4_ff_alloc_deviceid_node() parses the flexfiles device address from
a GETDEVICEINFO response and passes version_count to kzalloc_objs()
without validating it is non-zero. A zero count makes kzalloc_objs()
return ZERO_SIZE_PTR, which passes the NULL check.
This leads to a NULL pointer dereference when
nfs4_ff_layout_ds_version() later accesses ds_versions[0] through the
ZERO_SIZE_PTR.
Fix by rejecting version_count == 0 before the allocation.
Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
---
fs/nfs/flexfilelayout/flexfilelayoutdev.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index c40395ae0814..d5aa6bf3ecbc 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -99,6 +99,11 @@ nfs4_ff_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
version_count = be32_to_cpup(p);
dprintk("%s: version count %d\n", __func__, version_count);
+ if (version_count == 0) {
+ ret = -EINVAL;
+ goto out_err_drain_dsaddrs;
+ }
+
ds_versions = kzalloc_objs(struct nfs4_ff_ds_version, version_count,
gfp_flags);
if (!ds_versions)
---
base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
change-id: 20260420-fixes-9f910b7b5cde
Best regards,
--
Junrui Luo <moonafterrain@outlook.com>
reply other threads:[~2026-04-20 13:02 UTC|newest]
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