DivestOS/Patches/Linux_CVEs/CVE-2014-9875/ANY/0.patch

From b77c694b88a994d077316c157168c710696f8805 Mon Sep 17 00:00:00 2001
From: Ravi Aravamudhan <aravamud@codeaurora.org>
Date: Tue, 4 Jun 2013 10:10:11 -0700
Subject: diag: dci: Check for request pkt length being lesser than minimum
 length

Added checks for DCI request packets to be greater than the minimum
packet length. We would drop the request and print an error otherwise.

CRs-Fixed: 483310
Change-Id: I0d89ded58ee97a08ebe6b06b411ac17d2fcb11df
Signed-off-by: Ravi Aravamudhan <aravamud@codeaurora.org>
---
 drivers/char/diag/diag_dci.c | 114 ++++++++++++++++++++++++++++++++++---------
 drivers/char/diag/diag_dci.h |   3 ++
 2 files changed, 93 insertions(+), 24 deletions(-)

diff --git a/drivers/char/diag/diag_dci.c b/drivers/char/diag/diag_dci.c
index 9b404c6..fa0e9d7 100644
--- a/drivers/char/diag/diag_dci.c
+++ b/drivers/char/diag/diag_dci.c
@@ -375,16 +375,23 @@ void diag_dci_notify_client(int peripheral_mask, int data)
 int diag_send_dci_pkt(struct diag_master_table entry, unsigned char *buf,
 					 int len, int index)
 {
-	int i;
-	int status = 0;
+	int i, status = 0;
+	unsigned int read_len = 0;
 
-	/* remove UID from user space pkt before sending to peripheral */
-	buf = buf + 4;
+	/* The first 4 bytes is the uid tag and the next four bytes is
+	   the minmum packet length of a request packet */
+	if (len < DCI_PKT_REQ_MIN_LEN) {
+		pr_err("diag: dci: Invalid pkt len %d in %s\n", len, __func__);
+		return -EIO;
+	}
 	if (len > APPS_BUF_SIZE - 10) {
-		pr_err("diag: dci: buffer overwrite possible since payload bigger than buf size\n");
+		pr_err("diag: dci: Invalid payload length in %s\n", __func__);
 		return -EIO;
 	}
-	len = len - 4;
+	/* remove UID from user space pkt before sending to peripheral*/
+	buf = buf + sizeof(int);
+	read_len += sizeof(int);
+	len = len - sizeof(int);
 	mutex_lock(&driver->dci_mutex);
 	/* prepare DCI packet */
 	driver->apps_dci_buf[0] = CONTROL_CHAR; /* start */
@@ -395,7 +402,13 @@ int diag_send_dci_pkt(struct diag_master_table entry, unsigned char *buf,
 		driver->req_tracking_tbl[index].tag;
 	for (i = 0; i < len; i++)
 		driver->apps_dci_buf[i+9] = *(buf+i);
+	read_len += len;
 	driver->apps_dci_buf[9+len] = CONTROL_CHAR; /* end */
+	if ((read_len + 9) >= USER_SPACE_DATA) {
+		pr_err("diag: dci: Invalid length while forming dci pkt in %s",
+								__func__);
+		return -EIO;
+	}
 
 	for (i = 0; i < NUM_SMD_DCI_CHANNELS; i++) {
 		struct diag_smd_info *smd_info = driver->separate_cmdrsp[i] ?
@@ -449,10 +462,10 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 {
 	unsigned char *temp = buf;
 	uint16_t subsys_cmd_code, log_code, item_num;
-	int subsys_id, cmd_code, ret = -1, index = -1, found = 0, read_len = 0;
+	int subsys_id, cmd_code, ret = -1, index = -1, found = 0;
 	struct diag_master_table entry;
 	int count, set_mask, num_codes, bit_index, event_id, offset = 0, i;
-	unsigned int byte_index;
+	unsigned int byte_index, read_len = 0;
 	uint8_t equip_id, *log_mask_ptr, *head_log_mask_ptr, byte_mask;
 	uint8_t *event_mask_ptr;
 
@@ -462,15 +475,24 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 		return DIAG_DCI_SEND_DATA_FAIL;
 	}
 
+	if (!temp) {
+		pr_err("diag: Invalid buffer in %s\n", __func__);
+	}
+
 	/* This is Pkt request/response transaction */
 	if (*(int *)temp > 0) {
+		if (len < DCI_PKT_REQ_MIN_LEN || len > USER_SPACE_DATA) {
+			pr_err("diag: dci: Invalid length %d len in %s", len,
+								__func__);
+			return -EIO;
+		}
 		/* enter this UID into kernel table and return index */
 		index = diag_register_dci_transaction(*(int *)temp);
 		if (index < 0) {
 			pr_alert("diag: registering new DCI transaction failed\n");
 			return DIAG_DCI_NO_REG;
 		}
-		temp += 4;
+		temp += sizeof(int);
 		/*
 		 * Check for registered peripheral and fwd pkt to
 		 * appropriate proc
@@ -480,7 +502,12 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 		subsys_id = (int)(*(char *)temp);
 		temp++;
 		subsys_cmd_code = *(uint16_t *)temp;
-		temp += 2;
+		temp += sizeof(uint16_t);
+		read_len += sizeof(int) + 2 + sizeof(uint16_t);
+		if (read_len >= USER_SPACE_DATA) {
+			pr_err("diag: dci: Invalid length in %s\n", __func__);
+			return -EIO;
+		}
 		pr_debug("diag: %d %d %d", cmd_code, subsys_id,
 			subsys_cmd_code);
 		for (i = 0; i < diag_max_reg; i++) {
@@ -514,6 +541,12 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 			}
 		}
 	} else if (*(int *)temp == DCI_LOG_TYPE) {
+		/* Minimum length of a log mask config is 12 + 2 bytes for
+		   atleast one log code to be set or reset */
+		if (len < DCI_LOG_CON_MIN_LEN || len > USER_SPACE_DATA) {
+			pr_err("diag: dci: Invalid length in %s\n", __func__);
+			return -EIO;
+		}
 		/* find client id and table */
 		i = diag_dci_find_client_index(current->tgid);
 		if (i == DCI_CLIENT_INDEX_INVALID) {
@@ -521,21 +554,33 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 			return ret;
 		}
 		/* Extract each log code and put in client table */
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
 		set_mask = *(int *)temp;
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
 		num_codes = *(int *)temp;
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
+
+		if (num_codes == 0 || (num_codes >= (USER_SPACE_DATA - 8)/2)) {
+			pr_err("diag: dci: Invalid number of log codes %d\n",
+								num_codes);
+			return -EIO;
+		}
 
 		head_log_mask_ptr = driver->dci_client_tbl[i].dci_log_mask;
+		if (!head_log_mask_ptr) {
+			pr_err("diag: dci: Invalid Log mask pointer in %s\n",
+								__func__);
+			return -ENOMEM;
+		}
 		pr_debug("diag: head of dci log mask %p\n", head_log_mask_ptr);
 		count = 0; /* iterator for extracting log codes */
 		while (count < num_codes) {
 			if (read_len >= USER_SPACE_DATA) {
-				pr_err("diag: dci: Log type, possible buffer overflow\n");
+				pr_err("diag: dci: Invalid length for log type in %s",
+								__func__);
 				return -EIO;
 			}
 			log_code = *(uint16_t *)temp;
@@ -589,6 +634,12 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 		/* send updated mask to peripherals */
 		ret = diag_send_dci_log_mask(driver->smd_cntl[MODEM_DATA].ch);
 	} else if (*(int *)temp == DCI_EVENT_TYPE) {
+		/* Minimum length of a event mask config is 12 + 4 bytes for
+		  atleast one event id to be set or reset. */
+		if (len < DCI_EVENT_CON_MIN_LEN || len > USER_SPACE_DATA) {
+			pr_err("diag: dci: Invalid length in %s\n", __func__);
+			return -EIO;
+		}
 		/* find client id and table */
 		i = diag_dci_find_client_index(current->tgid);
 		if (i == DCI_CLIENT_INDEX_INVALID) {
@@ -596,21 +647,36 @@ int diag_process_dci_transaction(unsigned char *buf, int len)
 			return ret;
 		}
 		/* Extract each log code and put in client table */
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
 		set_mask = *(int *)temp;
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
 		num_codes = *(int *)temp;
-		temp += 4;
-		read_len += 4;
+		temp += sizeof(int);
+		read_len += sizeof(int);
+
+		/* Check for positive number of event ids. Also, the number of
+		   event ids should fit in the buffer along with set_mask and
+		   num_codes which are 4 bytes each */
+		if (num_codes == 0 || (num_codes >= (USER_SPACE_DATA - 8)/2)) {
+			pr_err("diag: dci: Invalid number of event ids %d\n",
+								num_codes);
+			return -EIO;
+		}
 
 		event_mask_ptr = driver->dci_client_tbl[i].dci_event_mask;
+		if (!event_mask_ptr) {
+			pr_err("diag: dci: Invalid event mask pointer in %s\n",
+								__func__);
+			return -ENOMEM;
+		}
 		pr_debug("diag: head of dci event mask %p\n", event_mask_ptr);
 		count = 0; /* iterator for extracting log codes */
 		while (count < num_codes) {
 			if (read_len >= USER_SPACE_DATA) {
-				pr_err("diag: dci: Event type, possible buffer overflow\n");
+				pr_err("diag: dci: Invalid length for event type in %s",
+								__func__);
 				return -EIO;
 			}
 			event_id = *(int *)temp;
diff --git a/drivers/char/diag/diag_dci.h b/drivers/char/diag/diag_dci.h
index 4dc1bfc..d530de9 100644
--- a/drivers/char/diag/diag_dci.h
+++ b/drivers/char/diag/diag_dci.h
@@ -24,6 +24,9 @@
 #define DISABLE_LOG_MASK	0
 #define MAX_EVENT_SIZE		512
 #define DCI_CLIENT_INDEX_INVALID -1
+#define DCI_PKT_REQ_MIN_LEN		8
+#define DCI_LOG_CON_MIN_LEN		14
+#define DCI_EVENT_CON_MIN_LEN		16
 
 
 /* 16 log code categories, each has:
-- 
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