commit 8aacfcf7abe5dbfa36841216fe4dd5e166bdada3
author Aditya Bavanari <abavanar@codeaurora.org> Fri Jun 21 15:56:39 2019 +0530
committer Aditya Bavanari <abavanar@codeaurora.org> Fri Jun 21 17:25:16 2019 +0530
tree 5b8127b8cba4ca51cb707814b2e381c971a73e5e
parent 45d02bcf0b2373346ac25e50168c95df9695027d

asoc: codecs: Fix out of bounds access in register show functions

In register show functions, when snprintf returns a negative value
out of bounds access occurs while copying the data to user.
Add return value check on snprintf before copy_to_user
to fix this.

Change-Id: I1eb793721c653bf6d1fbd10f4cea3436ffe6f519
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>

asoc/codecs/wsa881x.c

diff --git a/asoc/codecs/wsa881x.c b/asoc/codecs/wsa881x.c
index f98de2e..2871ad3 100644
--- a/asoc/codecs/wsa881x.c
+++ b/asoc/codecs/wsa881x.c
@@ -105,7 +105,7 @@
 
 #define SWR_SLV_MAX_REG_ADDR	0x390
 #define SWR_SLV_START_REG_ADDR	0x40
-#define SWR_SLV_MAX_BUF_LEN	20
+#define SWR_SLV_MAX_BUF_LEN	25
 #define BYTES_PER_LINE		12
 #define SWR_SLV_RD_BUF_LEN	8
 #define SWR_SLV_WR_BUF_LEN	32
@@ -393,6 +393,12 @@
 			i, &reg_val, 1);
 		len = snprintf(tmp_buf, 25, "0x%.3x: 0x%.2x\n", i,
 			       (reg_val & 0xFF));
+		if (len < 0) {
+			pr_err("%s: fail to fill the buffer\n", __func__);
+			total = -EFAULT;
+			goto copy_err;
+		}
+
 		if ((total + len) >= count - 1)
 			break;
 		if (copy_to_user((ubuf + total), tmp_buf, len)) {