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From: Chen Gang <gang.chen@asianux.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "paulus@samba.org" <paulus@samba.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Michael Ellerman <michael@ellerman.id.au>,
	"sfr@canb.auug.org.au" <sfr@canb.auug.org.au>
Subject: [PATCH] PowerPC: kernel: memory access violation when rtas_data_buf contents are more than 1026
Date: Tue, 23 Apr 2013 11:12:54 +0800	[thread overview]
Message-ID: <5175FC36.4060308@asianux.com> (raw)
In-Reply-To: <5175E85F.1040509@asianux.com>


need set '\0' for 'local_buffer'.

SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
rtas_data_buf may truncated in memcpy.

if contents are really truncated.
  the splpar_strlen is more than 1026. the next while loop checking will
  not find the end of buffer. that will cause memory access violation.


Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
 arch/powerpc/kernel/lparcfg.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 801a757..d92f387 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -299,6 +299,7 @@ static void parse_system_parameter_string(struct seq_file *m)
 				__pa(rtas_data_buf),
 				RTAS_DATA_BUF_SIZE);
 	memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
+	local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
 	spin_unlock(&rtas_data_buf_lock);
 
 	if (call_status != 0) {
-- 
1.7.7.6

  reply	other threads:[~2013-04-23  3:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-18  4:45 [Suggestion] PowerPC: kernel: memory access violation when rtas_data_buf contents are more than 1026 Chen Gang
2013-04-23  0:31 ` Benjamin Herrenschmidt
2013-04-23  1:48   ` Chen Gang
2013-04-23  3:12     ` Chen Gang [this message]
2013-04-24  6:28       ` [PATCH] " Vasant Hegde
2013-04-24  7:03         ` Chen Gang
2013-04-24  7:23           ` Vasant Hegde
2013-04-24  7:40             ` Chen Gang

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