netdev - [PATCH net-next v4] net/core: fix wrong return value in __splice

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250814010111.15167-1-hept.hept.hept@gmail.com>
Date: Thu, 14 Aug 2025 09:01:11 +0800
From: Pengtao He <hept.hept.hept@...il.com>
To: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Willem de Bruijn <willemb@...gle.com>,
	Mina Almasry <almasrymina@...gle.com>,
	Jason Xing <kerneljasonxing@...il.com>,
	Michal Luczaj <mhal@...x.co>,
	Eric Biggers <ebiggers@...gle.com>,
	Alexander Lobakin <aleksander.lobakin@...el.com>
Cc: netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Pengtao He <hept.hept.hept@...il.com>
Subject: [PATCH net-next v4] net/core: fix wrong return value in __splice_segment

If *len is equal to 0 at the beginning of __splice_segment
it returns true directly. But when decreasing *len from
a positive number to 0 in __splice_segment, it returns false.
The caller needs to call __splice_segment again.

Recheck *len if it changes, return true in time.
Reduce unnecessary calls to __splice_segment.

Signed-off-by: Pengtao He <hept.hept.hept@...il.com>
---
v4:
Correct the commit message.
v3:
Reduce once condition evaluation.
v2:
Correct the commit message and target tree.
v1:
https://lore.kernel.org/netdev/20250723063119.24059-1-hept.hept.hept@gmail.com/
---
 net/core/skbuff.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ee0274417948..23b776cd9879 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3112,7 +3112,9 @@ static bool __splice_segment(struct page *page, unsigned int poff,
 		poff += flen;
 		plen -= flen;
 		*len -= flen;
-	} while (*len && plen);
+		if (!*len)
+			return true;
+	} while (plen);
 
 	return false;
 }
-- 
2.49.0