From: Stefano Brivio <sbrivio@redhat.com>
To: passt-dev@passt.top
Cc: Jon Maloy <jmaloy@redhat.com>,
Paul Holzinger <pholzing@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v4 6/8] tcp: Cast operands of sequence comparison macros to uint32_t before using them
Date: Tue, 9 Sep 2025 20:16:53 +0200 [thread overview]
Message-ID: <20250909181655.2990223-7-sbrivio@redhat.com> (raw)
In-Reply-To: <20250909181655.2990223-1-sbrivio@redhat.com>
Otherwise, passing signed types causes automatic promotion of the
result of the subtractions as well, which is not what we want, as
these macros rely on unsigned 32-bit arithmetic.
The next patch introduces a ssize_t operand for SEQ_LE, illustrating
the issue.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
tcp_internal.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/tcp_internal.h b/tcp_internal.h
index d0009f8..ce6fee2 100644
--- a/tcp_internal.h
+++ b/tcp_internal.h
@@ -21,10 +21,14 @@
sizeof(struct ipv6hdr), \
sizeof(uint32_t))
-#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
-#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
-#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
-#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
+#define SEQ_LE(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) < MAX_WINDOW)
+#define SEQ_LT(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) - 1 < MAX_WINDOW)
+#define SEQ_GE(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) < MAX_WINDOW)
+#define SEQ_GT(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) - 1 < MAX_WINDOW)
#define FIN (1 << 0)
#define SYN (1 << 1)
--
@@ -21,10 +21,14 @@
sizeof(struct ipv6hdr), \
sizeof(uint32_t))
-#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
-#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
-#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
-#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
+#define SEQ_LE(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) < MAX_WINDOW)
+#define SEQ_LT(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) - 1 < MAX_WINDOW)
+#define SEQ_GE(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) < MAX_WINDOW)
+#define SEQ_GT(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) - 1 < MAX_WINDOW)
#define FIN (1 << 0)
#define SYN (1 << 1)
--
2.43.0
next prev parent reply other threads:[~2025-09-09 18:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-09 18:16 [PATCH v4 0/8] tcp: Fixes for issues uncovered by tests with 6.17-rc1 kernels Stefano Brivio
2025-09-09 18:16 ` [PATCH v4 1/8] tcp: FIN flags have to be retransmitted as well Stefano Brivio
2025-09-09 18:16 ` [PATCH v4 2/8] tcp: Factor sequence rewind for retransmissions into a new function Stefano Brivio
2025-09-09 18:16 ` [PATCH v4 3/8] tcp: Rewind sequence when guest shrinks window to zero Stefano Brivio
2025-09-10 2:20 ` David Gibson
2025-09-10 6:37 ` Stefano Brivio
2025-09-10 7:18 ` David Gibson
2025-09-10 23:48 ` Jon Maloy
2025-09-09 18:16 ` [PATCH v4 4/8] tcp: Fix closing logic for half-closed connections Stefano Brivio
2025-09-09 18:16 ` [PATCH v4 5/8] tcp: Don't try to transmit right after the peer shrank the window to zero Stefano Brivio
2025-09-09 18:16 ` Stefano Brivio [this message]
2025-09-10 2:21 ` [PATCH v4 6/8] tcp: Cast operands of sequence comparison macros to uint32_t before using them David Gibson
2025-09-09 18:16 ` [PATCH v4 7/8] tcp: Fast re-transmit if half-closed, make TAP_FIN_RCVD path consistent Stefano Brivio
2025-09-10 2:27 ` David Gibson
2025-09-10 9:57 ` Stefano Brivio
2025-09-09 18:16 ` [PATCH v4 8/8] tcp: Don't send FIN segment to guest yet if we have pending unacknowledged data Stefano Brivio
2025-09-10 2:29 ` David Gibson
2025-09-10 6:37 ` Stefano Brivio
2025-09-10 9:10 ` [PATCH v4 0/8] tcp: Fixes for issues uncovered by tests with 6.17-rc1 kernels Paul Holzinger
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