From: Atul Gopinathan <atulgopinathan@gmail.com>
To: gregkh@linuxfoundation.org
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
stable@vger.kernel.org,
Atul Gopinathan <atulgopinathan@gmail.com>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH v2 1/2] staging: rtl8192e: Fix incorrect source in memcpy()
Date: Tue, 23 Mar 2021 17:04:12 +0530 [thread overview]
Message-ID: <20210323113413.29179-1-atulgopinathan@gmail.com> (raw)
The variable "info_element" is of the following type:
struct rtllib_info_element *info_element
defined in drivers/staging/rtl8192e/rtllib.h:
struct rtllib_info_element {
u8 id;
u8 len;
u8 data[];
} __packed;
The "len" field defines the size of the "data[]" array. The code is
supposed to check if "info_element->len" is greater than 4 and later
equal to 6. If this is satisfied then, the last two bytes (the 4th and
5th element of u8 "data[]" array) are copied into "network->CcxRmState".
Right now the code uses "memcpy()" with the source as "&info_element[4]"
which would copy in wrong and unintended information. The struct
"rtllib_info_element" has a size of 2 bytes for "id" and "len",
therefore indexing will be done in interval of 2 bytes. So,
"info_element[4]" would point to data which is beyond the memory
allocated for this pointer (that is, at x+8, while "info_element" has
been allocated only from x to x+7 (2 + 6 => 8 bytes)).
This patch rectifies this error by using "&info_element->data[4]" which
correctly copies the last two bytes of "data[]".
NOTE: The faulty line of code came from the following commit:
commit ecdfa44610fa ("Staging: add Realtek 8192 PCI wireless driver")
The above commit created the file `rtl8192e/ieee80211/ieee80211_rx.c`
which had the faulty line of code. This file has been deleted (or
possibly renamed) with the contents copied in to a new file
`rtl8192e/rtllib_rx.c` along with additional code in the commit
94a799425eee (tagged in Fixes).
Fixes: 94a799425eee ("[PATCH 1/8] rtl8192e: Import new version of driver from realtek")
Cc: stable@vger.kernel.org
Signed-off-by: Atul Gopinathan <atulgopinathan@gmail.com>
---
drivers/staging/rtl8192e/rtllib_rx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/rtl8192e/rtllib_rx.c b/drivers/staging/rtl8192e/rtllib_rx.c
index 8415f26fd4c0..6e48b31a9afc 100644
--- a/drivers/staging/rtl8192e/rtllib_rx.c
+++ b/drivers/staging/rtl8192e/rtllib_rx.c
@@ -1965,15 +1965,15 @@ static void rtllib_parse_mife_generic(struct rtllib_device *ieee,
if (info_element->len > 4 &&
info_element->data[0] == 0x00 &&
info_element->data[1] == 0x40 &&
info_element->data[2] == 0x96 &&
info_element->data[3] == 0x01) {
if (info_element->len == 6) {
- memcpy(network->CcxRmState, &info_element[4], 2);
+ memcpy(network->CcxRmState, &info_element->data[4], 2);
if (network->CcxRmState[0] != 0)
network->bCcxRmEnable = true;
else
network->bCcxRmEnable = false;
network->MBssidMask = network->CcxRmState[1] & 0x07;
if (network->MBssidMask != 0) {
network->bMBssidValid = true;
--
2.25.1
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next reply other threads:[~2021-03-23 11:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 11:34 Atul Gopinathan [this message]
2021-03-23 11:34 ` [PATCH v2 2/2] staging: rtl8192e: Change state information from u16 to u8 Atul Gopinathan
2021-03-23 14:08 ` Dan Carpenter
2021-03-23 13:58 ` [PATCH v2 1/2] staging: rtl8192e: Fix incorrect source in memcpy() Dan Carpenter
2021-03-23 17:29 ` Atul Gopinathan
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