[PATCH 5.17 162/298] SUNRPC: Trap RDMA segment overflows

From: Greg Kroah-Hartman
Date: Mon Jun 13 2022 - 10:31:48 EST


From: Chuck Lever <chuck.lever@xxxxxxxxxx>

[ Upstream commit f012e95b377c73c0283f009823c633104dedb337 ]

Prevent svc_rdma_build_writes() from walking off the end of a Write
chunk's segment array. Caught with KASAN.

The test that this fix replaces is invalid, and might have been left
over from an earlier prototype of the PCL work.

Fixes: 7a1cbfa18059 ("svcrdma: Use parsed chunk lists to construct RDMA Writes")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/svc_rdma_rw.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 5f0155fdefc7..11cf7c646644 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -478,10 +478,10 @@ svc_rdma_build_writes(struct svc_rdma_write_info *info,
unsigned int write_len;
u64 offset;

- seg = &info->wi_chunk->ch_segments[info->wi_seg_no];
- if (!seg)
+ if (info->wi_seg_no >= info->wi_chunk->ch_segcount)
goto out_overflow;

+ seg = &info->wi_chunk->ch_segments[info->wi_seg_no];
write_len = min(remaining, seg->rs_length - info->wi_seg_off);
if (!write_len)
goto out_overflow;
--
2.35.1