netdev - [PATCH net] net: qed: prevent buffer overflow when collecting debug data

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Date:   Fri, 3 Jul 2020 12:02:58 +0300
From:   Alexander Lobakin <alobakin@...vell.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
CC:     Alexander Lobakin <alobakin@...vell.com>,
        Igor Russkikh <irusskikh@...vell.com>,
        Michal Kalderon <michal.kalderon@...vell.com>,
        "Ariel Elior" <aelior@...vell.com>,
        Denis Bolotin <denis.bolotin@...vell.com>,
        <GR-everest-linux-l2@...vell.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH net] net: qed: prevent buffer overflow when collecting debug data

When generating debug dump, driver firstly collects all data in binary
form, and then performs per-feature formatting to human-readable if it
is supported.
The size of the new formatted data is often larger than the raw's. This
becomes critical when user requests dump via ethtool (-d/-w), as output
buffer size is strictly determined (by ethtool_ops::get_regs_len() etc),
as it may lead to out-of-bounds writes and memory corruption.

To not go past initial lengths, add a flag to return original,
non-formatted debug data, and set it in such cases. Also set data type
in regdump headers, so userland parsers could handle it.

Fixes: c965db444629 ("qed: Add support for debug data collection")
Signed-off-by: Alexander Lobakin <alobakin@...vell.com>
Signed-off-by: Igor Russkikh <irusskikh@...vell.com>
---
 drivers/net/ethernet/qlogic/qed/qed.h       |  2 ++
 drivers/net/ethernet/qlogic/qed/qed_debug.c | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed.h b/drivers/net/ethernet/qlogic/qed/qed.h
index a49743d56b9c..6c2f9ff4a53e 100644
--- a/drivers/net/ethernet/qlogic/qed/qed.h
+++ b/drivers/net/ethernet/qlogic/qed/qed.h
@@ -876,6 +876,8 @@ struct qed_dev {
 	struct qed_dbg_feature dbg_features[DBG_FEATURE_NUM];
 	u8 engine_for_debug;
 	bool disable_ilt_dump;
+	bool				dbg_bin_dump;
+
 	DECLARE_HASHTABLE(connections, 10);
 	const struct firmware		*firmware;
 
diff --git a/drivers/net/ethernet/qlogic/qed/qed_debug.c b/drivers/net/ethernet/qlogic/qed/qed_debug.c
index 81e8fbe4a05b..cb80863d5a77 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_debug.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_debug.c
@@ -7506,6 +7506,12 @@ static enum dbg_status format_feature(struct qed_hwfn *p_hwfn,
 	if (p_hwfn->cdev->print_dbg_data)
 		qed_dbg_print_feature(text_buf, text_size_bytes);
 
+	/* Just return the original binary buffer if requested */
+	if (p_hwfn->cdev->dbg_bin_dump) {
+		vfree(text_buf);
+		return DBG_STATUS_OK;
+	}
+
 	/* Free the old dump_buf and point the dump_buf to the newly allocagted
 	 * and formatted text buffer.
 	 */
@@ -7733,7 +7739,9 @@ int qed_dbg_mcp_trace_size(struct qed_dev *cdev)
 #define REGDUMP_HEADER_SIZE_SHIFT		0
 #define REGDUMP_HEADER_SIZE_MASK		0xffffff
 #define REGDUMP_HEADER_FEATURE_SHIFT		24
-#define REGDUMP_HEADER_FEATURE_MASK		0x3f
+#define REGDUMP_HEADER_FEATURE_MASK		0x1f
+#define REGDUMP_HEADER_BIN_DUMP_SHIFT		29
+#define REGDUMP_HEADER_BIN_DUMP_MASK		0x1
 #define REGDUMP_HEADER_OMIT_ENGINE_SHIFT	30
 #define REGDUMP_HEADER_OMIT_ENGINE_MASK		0x1
 #define REGDUMP_HEADER_ENGINE_SHIFT		31
@@ -7771,6 +7779,7 @@ static u32 qed_calc_regdump_header(struct qed_dev *cdev,
 			  feature, feature_size);
 
 	SET_FIELD(res, REGDUMP_HEADER_FEATURE, feature);
+	SET_FIELD(res, REGDUMP_HEADER_BIN_DUMP, 1);
 	SET_FIELD(res, REGDUMP_HEADER_OMIT_ENGINE, omit_engine);
 	SET_FIELD(res, REGDUMP_HEADER_ENGINE, engine);
 
@@ -7794,6 +7803,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void *buffer)
 		omit_engine = 1;
 
 	mutex_lock(&qed_dbg_lock);
+	cdev->dbg_bin_dump = true;
 
 	org_engine = qed_get_debug_engine(cdev);
 	for (cur_engine = 0; cur_engine < cdev->num_hwfns; cur_engine++) {
@@ -7993,6 +8003,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void *buffer)
 		       QED_NVM_IMAGE_MDUMP, "QED_NVM_IMAGE_MDUMP", rc);
 	}
 
+	cdev->dbg_bin_dump = false;
 	mutex_unlock(&qed_dbg_lock);
 
 	return 0;
-- 
2.25.1