Re: [PATCH] i2c: fix stack buffer overflow vulnerability in i2c md command
On Fri, Jun 10, 2022 at 02:50:25PM +, nicolas.iooss.led...@proton.me wrote: > From: Nicolas Iooss > > When running "i2c md 0 0 8100", the function do_i2c_md parses the > length into an unsigned int variable named length. The value is then > moved to a signed variable: > > int nbytes = length; > #define DISP_LINE_LEN 16 > int linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes; > ret = dm_i2c_read(dev, addr, linebuf, linebytes); > > On systems where integers are 32 bits wide, 0x8100 is a negative > value to "nbytes > DISP_LINE_LEN" is false and linebytes gets assigned > 0x8100 instead of 16. > > The consequence is that the function which reads from the i2c device > (dm_i2c_read or i2c_read) is called with a 16-byte stack buffer to fill > but with a size parameter which is too large. In some cases, this could > trigger a crash. But with some i2c drivers, such as drivers/i2c/nx_i2c.c > (used with "nexell,s5pxx18-i2c" bus), the size is actually truncated to > a 16-bit integer. This is because function i2c_transfer expects an > unsigned short length. In such a case, an attacker who can control the > response of an i2c device can overwrite the return address of a function > and execute arbitrary code through Return-Oriented Programming. > > Fix this issue by using unsigned integers types in do_i2c_md. While at > it, make also alen unsigned, as signed sizes can cause vulnerabilities > when people forgot to check that they can be negative. > > Signed-off-by: Nicolas Iooss > Reviewed-by: Heiko Schocher Applied to u-boot/master, thanks! -- Tom signature.asc Description: PGP signature
Re: [PATCH] i2c: fix stack buffer overflow vulnerability in i2c md command
On Mon, Jun 27, 2022 at 06:33:01AM +0200, Heiko Schocher wrote: > Hello Nicolas, > > On 21.06.22 16:04, Nicolas IOOSS wrote: > > Hello, > > > > I sent some days ago the vulnerability fix below. I have not received any > > reply yet. Could a maintainer take a look at it, please? > > Sorry for that, but I was on the road (embedded world in nuremberg). > > > Best regards, > > Nicolas > > > > --- Original Message --- > > Le vendredi 10 juin 2022 à 4:50 PM, a > > écrit : > > > > > >> From: Nicolas Iooss nicolas.iooss+ub...@ledger.fr > >> > >> > >> When running "i2c md 0 0 8100", the function do_i2c_md parses the > >> length into an unsigned int variable named length. The value is then > >> moved to a signed variable: > >> > >> int nbytes = length; > >> #define DISP_LINE_LEN 16 > >> int linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes; > >> > >> ret = dm_i2c_read(dev, addr, linebuf, linebytes); > >> > >> On systems where integers are 32 bits wide, 0x8100 is a negative > >> value to "nbytes > DISP_LINE_LEN" is false and linebytes gets assigned > >> > >> 0x8100 instead of 16. > >> > >> The consequence is that the function which reads from the i2c device > >> (dm_i2c_read or i2c_read) is called with a 16-byte stack buffer to fill > >> but with a size parameter which is too large. In some cases, this could > >> trigger a crash. But with some i2c drivers, such as drivers/i2c/nx_i2c.c > >> (used with "nexell,s5pxx18-i2c" bus), the size is actually truncated to > >> a 16-bit integer. This is because function i2c_transfer expects an > >> unsigned short length. In such a case, an attacker who can control the > >> response of an i2c device can overwrite the return address of a function > >> and execute arbitrary code through Return-Oriented Programming. > >> > >> Fix this issue by using unsigned integers types in do_i2c_md. While at > >> it, make also alen unsigned, as signed sizes can cause vulnerabilities > >> when people forgot to check that they can be negative. > >> > >> Signed-off-by: Nicolas Iooss nicolas.iooss+ub...@ledger.fr > >> > >> --- > >> cmd/i2c.c | 24 > >> 1 file changed, 12 insertions(+), 12 deletions(-) > > Reviewed-by: Heiko Schocher > > @Tom: Should we add this to 2022.07? If so, feel free to pick it up, > thanks! I'll pick this up directly along with the squashfs fix in the next day or two, thanks. -- Tom signature.asc Description: PGP signature
Re: [PATCH] i2c: fix stack buffer overflow vulnerability in i2c md command
Hello Nicolas, On 21.06.22 16:04, Nicolas IOOSS wrote: > Hello, > > I sent some days ago the vulnerability fix below. I have not received any > reply yet. Could a maintainer take a look at it, please? Sorry for that, but I was on the road (embedded world in nuremberg). > Best regards, > Nicolas > > --- Original Message --- > Le vendredi 10 juin 2022 à 4:50 PM, a écrit : > > >> From: Nicolas Iooss nicolas.iooss+ub...@ledger.fr >> >> >> When running "i2c md 0 0 8100", the function do_i2c_md parses the >> length into an unsigned int variable named length. The value is then >> moved to a signed variable: >> >> int nbytes = length; >> #define DISP_LINE_LEN 16 >> int linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes; >> >> ret = dm_i2c_read(dev, addr, linebuf, linebytes); >> >> On systems where integers are 32 bits wide, 0x8100 is a negative >> value to "nbytes > DISP_LINE_LEN" is false and linebytes gets assigned >> >> 0x8100 instead of 16. >> >> The consequence is that the function which reads from the i2c device >> (dm_i2c_read or i2c_read) is called with a 16-byte stack buffer to fill >> but with a size parameter which is too large. In some cases, this could >> trigger a crash. But with some i2c drivers, such as drivers/i2c/nx_i2c.c >> (used with "nexell,s5pxx18-i2c" bus), the size is actually truncated to >> a 16-bit integer. This is because function i2c_transfer expects an >> unsigned short length. In such a case, an attacker who can control the >> response of an i2c device can overwrite the return address of a function >> and execute arbitrary code through Return-Oriented Programming. >> >> Fix this issue by using unsigned integers types in do_i2c_md. While at >> it, make also alen unsigned, as signed sizes can cause vulnerabilities >> when people forgot to check that they can be negative. >> >> Signed-off-by: Nicolas Iooss nicolas.iooss+ub...@ledger.fr >> >> --- >> cmd/i2c.c | 24 >> 1 file changed, 12 insertions(+), 12 deletions(-) Reviewed-by: Heiko Schocher @Tom: Should we add this to 2022.07? If so, feel free to pick it up, thanks! bye, Heiko -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-52 Fax: +49-8142-66989-80 Email: h...@denx.de
Re: [PATCH] i2c: fix stack buffer overflow vulnerability in i2c md command
Hello,
I sent some days ago the vulnerability fix below. I have not received any reply
yet. Could a maintainer take a look at it, please?
Best regards,
Nicolas
--- Original Message ---
Le vendredi 10 juin 2022 à 4:50 PM, a écrit :
> From: Nicolas Iooss nicolas.iooss+ub...@ledger.fr
>
>
> When running "i2c md 0 0 8100", the function do_i2c_md parses the
> length into an unsigned int variable named length. The value is then
> moved to a signed variable:
>
> int nbytes = length;
> #define DISP_LINE_LEN 16
> int linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes;
>
> ret = dm_i2c_read(dev, addr, linebuf, linebytes);
>
> On systems where integers are 32 bits wide, 0x8100 is a negative
> value to "nbytes > DISP_LINE_LEN" is false and linebytes gets assigned
>
> 0x8100 instead of 16.
>
> The consequence is that the function which reads from the i2c device
> (dm_i2c_read or i2c_read) is called with a 16-byte stack buffer to fill
> but with a size parameter which is too large. In some cases, this could
> trigger a crash. But with some i2c drivers, such as drivers/i2c/nx_i2c.c
> (used with "nexell,s5pxx18-i2c" bus), the size is actually truncated to
> a 16-bit integer. This is because function i2c_transfer expects an
> unsigned short length. In such a case, an attacker who can control the
> response of an i2c device can overwrite the return address of a function
> and execute arbitrary code through Return-Oriented Programming.
>
> Fix this issue by using unsigned integers types in do_i2c_md. While at
> it, make also alen unsigned, as signed sizes can cause vulnerabilities
> when people forgot to check that they can be negative.
>
> Signed-off-by: Nicolas Iooss nicolas.iooss+ub...@ledger.fr
>
> ---
> cmd/i2c.c | 24
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/cmd/i2c.c b/cmd/i2c.c
> index 9050b2b8d27a..bd04b14024be 100644
> --- a/cmd/i2c.c
> +++ b/cmd/i2c.c
> @@ -200,10 +200,10 @@ void i2c_init_board(void)
> *
> * Returns the address length.
> */
> -static uint get_alen(char *arg, int default_len)
> +static uint get_alen(char *arg, uint default_len)
> {
> - int j;
> - int alen;
> + uint j;
> + uint alen;
>
> alen = default_len;
> for (j = 0; j < 8; j++) {
> @@ -247,7 +247,7 @@ static int do_i2c_read(struct cmd_tbl *cmdtp, int flag,
> int argc,
> {
> uint chip;
> uint devaddr, length;
> - int alen;
> + uint alen;
> u_char *memaddr;
> int ret;
> #if CONFIG_IS_ENABLED(DM_I2C)
> @@ -301,7 +301,7 @@ static int do_i2c_write(struct cmd_tbl *cmdtp, int flag,
> int argc,
> {
> uint chip;
> uint devaddr, length;
> - int alen;
> + uint alen;
> u_char *memaddr;
> int ret;
> #if CONFIG_IS_ENABLED(DM_I2C)
> @@ -469,8 +469,8 @@ static int do_i2c_md(struct cmd_tbl *cmdtp, int flag, int
> argc,
> {
> uint chip;
> uint addr, length;
> - int alen;
> - int j, nbytes, linebytes;
> + uint alen;
> + uint j, nbytes, linebytes;
> int ret;
> #if CONFIG_IS_ENABLED(DM_I2C)
> struct udevice *dev;
> @@ -589,9 +589,9 @@ static int do_i2c_mw(struct cmd_tbl *cmdtp, int flag, int
> argc,
> {
> uint chip;
> ulong addr;
> - int alen;
> + uint alen;
> uchar byte;
> - int count;
> + uint count;
> int ret;
> #if CONFIG_IS_ENABLED(DM_I2C)
> struct udevice *dev;
> @@ -676,8 +676,8 @@ static int do_i2c_crc(struct cmd_tbl *cmdtp, int flag,
> int argc,
> {
> uint chip;
> ulong addr;
> - int alen;
> - int count;
> + uint alen;
> + uint count;
> uchar byte;
> ulong crc;
> ulong err;
> @@ -985,7 +985,7 @@ static int do_i2c_loop(struct cmd_tbl *cmdtp, int flag,
> int argc,
> char *const argv[])
> {
> uint chip;
> - int alen;
> + uint alen;
> uint addr;
> uint length;
> u_char bytes[16];
> --
> 2.32.0
[PATCH] i2c: fix stack buffer overflow vulnerability in i2c md command
From: Nicolas Iooss
When running "i2c md 0 0 8100", the function do_i2c_md parses the
length into an unsigned int variable named length. The value is then
moved to a signed variable:
int nbytes = length;
#define DISP_LINE_LEN 16
int linebytes = (nbytes > DISP_LINE_LEN) ? DISP_LINE_LEN : nbytes;
ret = dm_i2c_read(dev, addr, linebuf, linebytes);
On systems where integers are 32 bits wide, 0x8100 is a negative
value to "nbytes > DISP_LINE_LEN" is false and linebytes gets assigned
0x8100 instead of 16.
The consequence is that the function which reads from the i2c device
(dm_i2c_read or i2c_read) is called with a 16-byte stack buffer to fill
but with a size parameter which is too large. In some cases, this could
trigger a crash. But with some i2c drivers, such as drivers/i2c/nx_i2c.c
(used with "nexell,s5pxx18-i2c" bus), the size is actually truncated to
a 16-bit integer. This is because function i2c_transfer expects an
unsigned short length. In such a case, an attacker who can control the
response of an i2c device can overwrite the return address of a function
and execute arbitrary code through Return-Oriented Programming.
Fix this issue by using unsigned integers types in do_i2c_md. While at
it, make also alen unsigned, as signed sizes can cause vulnerabilities
when people forgot to check that they can be negative.
Signed-off-by: Nicolas Iooss
---
cmd/i2c.c | 24
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/cmd/i2c.c b/cmd/i2c.c
index 9050b2b8d27a..bd04b14024be 100644
--- a/cmd/i2c.c
+++ b/cmd/i2c.c
@@ -200,10 +200,10 @@ void i2c_init_board(void)
*
* Returns the address length.
*/
-static uint get_alen(char *arg, int default_len)
+static uint get_alen(char *arg, uint default_len)
{
- int j;
- int alen;
+ uintj;
+ uintalen;
alen = default_len;
for (j = 0; j < 8; j++) {
@@ -247,7 +247,7 @@ static int do_i2c_read(struct cmd_tbl *cmdtp, int flag, int
argc,
{
uintchip;
uintdevaddr, length;
- int alen;
+ uintalen;
u_char *memaddr;
int ret;
#if CONFIG_IS_ENABLED(DM_I2C)
@@ -301,7 +301,7 @@ static int do_i2c_write(struct cmd_tbl *cmdtp, int flag,
int argc,
{
uintchip;
uintdevaddr, length;
- int alen;
+ uintalen;
u_char *memaddr;
int ret;
#if CONFIG_IS_ENABLED(DM_I2C)
@@ -469,8 +469,8 @@ static int do_i2c_md(struct cmd_tbl *cmdtp, int flag, int
argc,
{
uintchip;
uintaddr, length;
- int alen;
- int j, nbytes, linebytes;
+ uintalen;
+ uintj, nbytes, linebytes;
int ret;
#if CONFIG_IS_ENABLED(DM_I2C)
struct udevice *dev;
@@ -589,9 +589,9 @@ static int do_i2c_mw(struct cmd_tbl *cmdtp, int flag, int
argc,
{
uintchip;
ulong addr;
- int alen;
+ uintalen;
uchar byte;
- int count;
+ uintcount;
int ret;
#if CONFIG_IS_ENABLED(DM_I2C)
struct udevice *dev;
@@ -676,8 +676,8 @@ static int do_i2c_crc(struct cmd_tbl *cmdtp, int flag, int
argc,
{
uintchip;
ulong addr;
- int alen;
- int count;
+ uintalen;
+ uintcount;
uchar byte;
ulong crc;
ulong err;
@@ -985,7 +985,7 @@ static int do_i2c_loop(struct cmd_tbl *cmdtp, int flag, int
argc,
char *const argv[])
{
uintchip;
- int alen;
+ uintalen;
uintaddr;
uintlength;
u_char bytes[16];
--
2.32.0
