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From: Jason Wang <jasowang@redhat.com>
To: peter.maydell@linaro.org, qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>,
	Jason Wang <jasowang@redhat.com>
Subject: [PULL] hw/net/rocker: Avoid undefined shifts with more than 31 ports
Date: Tue,  9 Aug 2022 17:08:59 +0800	[thread overview]
Message-ID: <20220809090859.28338-2-jasowang@redhat.com> (raw)
In-Reply-To: <20220809090859.28338-1-jasowang@redhat.com>

From: Peter Maydell <peter.maydell@linaro.org>

In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
we construct a 64-bit value with one bit per front-panel port.
However we accidentally do the shift as 32-bit arithmetic, which
means that if there are more than 31 front-panel ports this is
undefined behaviour.

Fix the problem by ensuring we use 64-bit arithmetic for the whole
calculation. (We won't ever shift off the 64-bit value because
ROCKER_FP_PORTS_MAX is 62.)

Resolves: Coverity CID 1487121, 1487160
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/rocker/rocker.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
index 31f2340..d8f3f16 100644
--- a/hw/net/rocker/rocker.c
+++ b/hw/net/rocker/rocker.c
@@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
         FpPort *port = r->fp_port[i];
 
         if (fp_port_get_link_up(port)) {
-            status |= 1 << (i + 1);
+            status |= 1ULL << (i + 1);
         }
     }
     return status;
@@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
         FpPort *port = r->fp_port[i];
 
         if (fp_port_enabled(port)) {
-            ret |= 1 << (i + 1);
+            ret |= 1ULL << (i + 1);
         }
     }
     return ret;
-- 
2.7.4



  reply	other threads:[~2022-08-09  9:11 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-09  9:08 [PULL] Net patches Jason Wang
2022-08-09  9:08 ` Jason Wang [this message]
2022-08-09 16:43 ` Richard Henderson

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