linux-kernel - [PATCH] TPM: Avoid reference to potentially freed memory

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Message-Id: <1445545961-5620-1-git-send-email-christophe.jaillet@wanadoo.fr>
Date:	Thu, 22 Oct 2015 22:32:41 +0200
From:	Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:	peterhuewe@....de, tpmdd@...horst.net,
	jarkko.sakkinen@...ux.intel.com
Cc:	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] TPM: Avoid reference to potentially freed memory

Reference to the 'np' node is dropped before dereferencing the 'sizep' and
'basep' pointers, which could by then point to junk if the node has been
freed.

Refactor code to call 'of_node_pup' later.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/char/tpm/tpm_of.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 1141456..570f30c 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -53,17 +53,18 @@ int read_log(struct tpm_bios_log *log)
 		goto cleanup_eio;
 	}
 
-	of_node_put(np);
 	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
 	if (!log->bios_event_log) {
 		pr_err("%s: ERROR - Not enough memory for BIOS measurements\n",
 		       __func__);
+		of_node_put(np);
 		return -ENOMEM;
 	}
 
 	log->bios_event_log_end = log->bios_event_log + *sizep;
 
 	memcpy(log->bios_event_log, __va(*basep), *sizep);
+	of_node_put(np);
 
 	return 0;
 
-- 
2.1.4

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