The param_set_fn() function will get a parameter which is a NULL
pointer when insmod module via bare params as following method:
$insmod foo.ko foo
If the param_set_fn() function didn't check that parameter and used
it directly, it could caused an OOPS due to NULL pointer dereference.
The solution is simple:
Using "" to replace NULL parameter, thereby the param_set_fn()
function will never get a NULL pointer.
Signed-off-by: Dongdong Deng <[email protected]>
---
kernel/params.c | 30 ++++++------------------------
1 files changed, 6 insertions(+), 24 deletions(-)
diff --git a/kernel/params.c b/kernel/params.c
index cf1b691..548d680 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -101,7 +101,11 @@ static char *next_arg(char *args, char **param, char **val)
*param = args;
if (!equals)
- *val = NULL;
+ /*
+ * We used to hand NULL for bare params, but most code
+ * didn't handle it. Using "" to replace NULL here.
+ */
+ *val = "";
else {
args[equals] = '\0';
*val = args + equals + 1;
@@ -180,10 +184,7 @@ int parse_args(const char *name,
int param_set_##name(const char *val, struct kernel_param *kp) \
{ \
tmptype l; \
- int ret; \
- \
- if (!val) return -EINVAL; \
- ret = strtolfn(val, 0, &l); \
+ int ret = strtolfn(val, 0, &l); \
if (ret == -EINVAL || ((type)l != l)) \
return -EINVAL; \
*((type *)kp->arg) = l; \
@@ -204,12 +205,6 @@ STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
int param_set_charp(const char *val, struct kernel_param *kp)
{
- if (!val) {
- printk(KERN_ERR "%s: string parameter expected\n",
- kp->name);
- return -EINVAL;
- }
-
if (strlen(val) > 1024) {
printk(KERN_ERR "%s: string parameter too long\n",
kp->name);
@@ -238,9 +233,6 @@ int param_set_bool(const char *val, struct kernel_param *kp)
{
bool v;
- /* No equals means "set"... */
- if (!val) val = "1";
-
/* One of =[yYnN01] */
switch (val[0]) {
case 'y': case 'Y': case '1':
@@ -310,12 +302,6 @@ static int param_array(const char *name,
kp.arg = elem;
kp.flags = flags;
- /* No equals sign? */
- if (!val) {
- printk(KERN_ERR "%s: expects arguments\n", name);
- return -EINVAL;
- }
-
*num = 0;
/* We expect a comma-separated list of values. */
do {
@@ -382,10 +368,6 @@ int param_set_copystring(const char *val, struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
- if (!val) {
- printk(KERN_ERR "%s: missing param set value\n", kp->name);
- return -EINVAL;
- }
if (strlen(val)+1 > kps->maxlen) {
printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
kp->name, kps->maxlen-1);
--
1.6.0.4
On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
> The param_set_fn() function will get a parameter which is a NULL
> pointer when insmod module via bare params as following method:
>
> $insmod foo.ko foo
>
> If the param_set_fn() function didn't check that parameter and used
> it directly, it could caused an OOPS due to NULL pointer dereference.
>
> The solution is simple:
> Using "" to replace NULL parameter, thereby the param_set_fn()
> function will never get a NULL pointer.
This changes the value of booleans, and loses checking for int params, etc.
I liked Americo's approach; I've combined the two approaches below.
Since I'm going away, can Andrew take this?
Subject: params: don't hand NULL values to param.set callbacks.
An audit by Dongdong Deng revealed that most driver-author-written param
calls don't handle val == NULL (which happens when parameters are specified
with no =, eg "foo" instead of "foo=1").
The only real case to use this is boolean, so handle it specially for that
case and remove a source of bugs for everyone else as suggested by Americo.
Signed-off-by: Rusty Russell <[email protected]>
Cc: Dongdong Deng <[email protected]>
Cc: Am?rico Wang <[email protected]>
diff --git a/kernel/params.c b/kernel/params.c
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -59,6 +59,9 @@ static int parse_one(char *param,
/* Find parameter */
for (i = 0; i < num_params; i++) {
if (parameq(param, params[i].name)) {
+ /* Noone handled NULL, so do it here. */
+ if (!val && params[i].set != param_set_bool)
+ return -EINVAL;
DEBUGP("They are equal! Calling %p\n",
params[i].set);
return params[i].set(val, ¶ms[i]);
@@ -182,7 +185,6 @@ int parse_args(const char *name,
tmptype l; \
int ret; \
\
- if (!val) return -EINVAL; \
ret = strtolfn(val, 0, &l); \
if (ret == -EINVAL || ((type)l != l)) \
return -EINVAL; \
@@ -204,12 +206,6 @@ STANDARD_PARAM_DEF(ulong, unsigned long,
int param_set_charp(const char *val, struct kernel_param *kp)
{
- if (!val) {
- printk(KERN_ERR "%s: string parameter expected\n",
- kp->name);
- return -EINVAL;
- }
-
if (strlen(val) > 1024) {
printk(KERN_ERR "%s: string parameter too long\n",
kp->name);
@@ -310,12 +306,6 @@ static int param_array(const char *name,
kp.arg = elem;
kp.flags = flags;
- /* No equals sign? */
- if (!val) {
- printk(KERN_ERR "%s: expects arguments\n", name);
- return -EINVAL;
- }
-
*num = 0;
/* We expect a comma-separated list of values. */
do {
@@ -382,10 +372,6 @@ int param_set_copystring(const char *val
{
const struct kparam_string *kps = kp->str;
- if (!val) {
- printk(KERN_ERR "%s: missing param set value\n", kp->name);
- return -EINVAL;
- }
if (strlen(val)+1 > kps->maxlen) {
printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
kp->name, kps->maxlen-1);
--
Away travelling 25Feb-26Mar (6 .de + 1 .pl + 17 .lt + 2 .sg)
On Tue, Feb 23, 2010 at 11:56 AM, Rusty Russell <[email protected]> wrote:
> On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
>> The param_set_fn() function will get a parameter which is a NULL
>> pointer when insmod module via bare params as following method:
>>
>> $insmod foo.ko foo
>>
>> If the param_set_fn() function didn't check that parameter and used
>> it directly, it could caused an OOPS due to NULL pointer dereference.
>>
>> The solution is simple:
>> Using "" to replace NULL parameter, thereby the param_set_fn()
>> function will never get a NULL pointer.
>
> This changes the value of booleans, and loses checking for int params, etc.
>
> I liked Americo's approach; I've combined the two approaches below.
>
> Since I'm going away, can Andrew take this?
>
> Subject: params: don't hand NULL values to param.set callbacks.
>
> An audit by Dongdong Deng revealed that most driver-author-written param
> calls don't handle val == NULL (which happens when parameters are specified
> with no =, eg "foo" instead of "foo=1").
>
> The only real case to use this is boolean, so handle it specially for that
> case and remove a source of bugs for everyone else as suggested by Americo.
>
Yeah, thanks, this one looks better than mine.
Acked-by: WANG Cong <[email protected]>
Rusty Russell wrote:
> On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
>> The param_set_fn() function will get a parameter which is a NULL
>> pointer when insmod module via bare params as following method:
>>
>> $insmod foo.ko foo
>>
>> If the param_set_fn() function didn't check that parameter and used
>> it directly, it could caused an OOPS due to NULL pointer dereference.
>>
>> The solution is simple:
>> Using "" to replace NULL parameter, thereby the param_set_fn()
>> function will never get a NULL pointer.
>
> This changes the value of booleans, and loses checking for int params, etc.
>
> I liked Americo's approach; I've combined the two approaches below.
Thanks for your correcting.
Acked-by: Dongdong Deng <[email protected]>
>
> Since I'm going away, can Andrew take this?
>
> Subject: params: don't hand NULL values to param.set callbacks.
>
> An audit by Dongdong Deng revealed that most driver-author-written param
> calls don't handle val == NULL (which happens when parameters are specified
> with no =, eg "foo" instead of "foo=1").
>
> The only real case to use this is boolean, so handle it specially for that
> case and remove a source of bugs for everyone else as suggested by Americo.
>
> Signed-off-by: Rusty Russell <[email protected]>
> Cc: Dongdong Deng <[email protected]>
> Cc: Am?rico Wang <[email protected]>
>
> diff --git a/kernel/params.c b/kernel/params.c
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -59,6 +59,9 @@ static int parse_one(char *param,
> /* Find parameter */
> for (i = 0; i < num_params; i++) {
> if (parameq(param, params[i].name)) {
> + /* Noone handled NULL, so do it here. */
> + if (!val && params[i].set != param_set_bool)
> + return -EINVAL;
> DEBUGP("They are equal! Calling %p\n",
> params[i].set);
> return params[i].set(val, ¶ms[i]);
> @@ -182,7 +185,6 @@ int parse_args(const char *name,
> tmptype l; \
> int ret; \
> \
> - if (!val) return -EINVAL; \
> ret = strtolfn(val, 0, &l); \
> if (ret == -EINVAL || ((type)l != l)) \
> return -EINVAL; \
> @@ -204,12 +206,6 @@ STANDARD_PARAM_DEF(ulong, unsigned long,
>
> int param_set_charp(const char *val, struct kernel_param *kp)
> {
> - if (!val) {
> - printk(KERN_ERR "%s: string parameter expected\n",
> - kp->name);
> - return -EINVAL;
> - }
> -
> if (strlen(val) > 1024) {
> printk(KERN_ERR "%s: string parameter too long\n",
> kp->name);
> @@ -310,12 +306,6 @@ static int param_array(const char *name,
> kp.arg = elem;
> kp.flags = flags;
>
> - /* No equals sign? */
> - if (!val) {
> - printk(KERN_ERR "%s: expects arguments\n", name);
> - return -EINVAL;
> - }
> -
> *num = 0;
> /* We expect a comma-separated list of values. */
> do {
> @@ -382,10 +372,6 @@ int param_set_copystring(const char *val
> {
> const struct kparam_string *kps = kp->str;
>
> - if (!val) {
> - printk(KERN_ERR "%s: missing param set value\n", kp->name);
> - return -EINVAL;
> - }
> if (strlen(val)+1 > kps->maxlen) {
> printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
> kp->name, kps->maxlen-1);
>
On Tue, Feb 23, 2010 at 02:26:45PM +1030, Rusty Russell wrote:
>On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
>> The param_set_fn() function will get a parameter which is a NULL
>> pointer when insmod module via bare params as following method:
>>
>> $insmod foo.ko foo
>>
>> If the param_set_fn() function didn't check that parameter and used
>> it directly, it could caused an OOPS due to NULL pointer dereference.
>>
>> The solution is simple:
>> Using "" to replace NULL parameter, thereby the param_set_fn()
>> function will never get a NULL pointer.
>
>This changes the value of booleans, and loses checking for int params, etc.
>
>I liked Americo's approach; I've combined the two approaches below.
>
>Since I'm going away, can Andrew take this?
>
>Subject: params: don't hand NULL values to param.set callbacks.
>
>An audit by Dongdong Deng revealed that most driver-author-written param
>calls don't handle val == NULL (which happens when parameters are specified
>with no =, eg "foo" instead of "foo=1").
>
>The only real case to use this is boolean, so handle it specially for that
>case and remove a source of bugs for everyone else as suggested by Americo.
>
>Signed-off-by: Rusty Russell <[email protected]>
>Cc: Dongdong Deng <[email protected]>
>Cc: Américo Wang <[email protected]>
>
>diff --git a/kernel/params.c b/kernel/params.c
>--- a/kernel/params.c
>+++ b/kernel/params.c
>@@ -59,6 +59,9 @@ static int parse_one(char *param,
> /* Find parameter */
> for (i = 0; i < num_params; i++) {
> if (parameq(param, params[i].name)) {
>+ /* Noone handled NULL, so do it here. */
>+ if (!val && params[i].set != param_set_bool)
>+ return -EINVAL;
Sorry, after rethinking about this, I think it might be wrong.
With this patch, when I use non-standard bool functions, I will not
have a chance to use '!val' which should be valid for all bool
functions. Or am I missing something?
Thanks.
On Wed, 24 Feb 2010 02:15:19 am Américo Wang wrote:
> On Tue, Feb 23, 2010 at 02:26:45PM +1030, Rusty Russell wrote:
> >On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
> >> The param_set_fn() function will get a parameter which is a NULL
> >> pointer when insmod module via bare params as following method:
> >>
> >> $insmod foo.ko foo
> >>
> >> If the param_set_fn() function didn't check that parameter and used
> >> it directly, it could caused an OOPS due to NULL pointer dereference.
> >>
> >> The solution is simple:
> >> Using "" to replace NULL parameter, thereby the param_set_fn()
> >> function will never get a NULL pointer.
> >
> >This changes the value of booleans, and loses checking for int params, etc.
> >
> >I liked Americo's approach; I've combined the two approaches below.
> >
> >Since I'm going away, can Andrew take this?
> >
> >Subject: params: don't hand NULL values to param.set callbacks.
> >
> >An audit by Dongdong Deng revealed that most driver-author-written param
> >calls don't handle val == NULL (which happens when parameters are specified
> >with no =, eg "foo" instead of "foo=1").
> >
> >The only real case to use this is boolean, so handle it specially for that
> >case and remove a source of bugs for everyone else as suggested by Americo.
> >
> >Signed-off-by: Rusty Russell <[email protected]>
> >Cc: Dongdong Deng <[email protected]>
> >Cc: Américo Wang <[email protected]>
> >
> >diff --git a/kernel/params.c b/kernel/params.c
> >--- a/kernel/params.c
> >+++ b/kernel/params.c
> >@@ -59,6 +59,9 @@ static int parse_one(char *param,
> > /* Find parameter */
> > for (i = 0; i < num_params; i++) {
> > if (parameq(param, params[i].name)) {
> >+ /* Noone handled NULL, so do it here. */
> >+ if (!val && params[i].set != param_set_bool)
> >+ return -EINVAL;
>
> Sorry, after rethinking about this, I think it might be wrong.
>
> With this patch, when I use non-standard bool functions, I will not
> have a chance to use '!val' which should be valid for all bool
> functions. Or am I missing something?
Sure, at that point we'd need something more sophisticated. But to
fix this properly we want a flags word, and thus something like this
which I worked on earlier:
http://ozlabs.org/~rusty/kernel/rr-latest/param:param_ops.patch
Cheers,
Rusty.
--
Away travelling 25Feb-26Mar (6 .de + 1 .pl + 17 .lt + 2 .sg)
On Wed, Feb 24, 2010 at 9:01 AM, Rusty Russell <[email protected]> wrote:
> On Wed, 24 Feb 2010 02:15:19 am Américo Wang wrote:
>> On Tue, Feb 23, 2010 at 02:26:45PM +1030, Rusty Russell wrote:
>> >On Mon, 22 Feb 2010 09:10:51 pm Dongdong Deng wrote:
>> >> The param_set_fn() function will get a parameter which is a NULL
>> >> pointer when insmod module via bare params as following method:
>> >>
>> >> $insmod foo.ko foo
>> >>
>> >> If the param_set_fn() function didn't check that parameter and used
>> >> it directly, it could caused an OOPS due to NULL pointer dereference.
>> >>
>> >> The solution is simple:
>> >> Using "" to replace NULL parameter, thereby the param_set_fn()
>> >> function will never get a NULL pointer.
>> >
>> >This changes the value of booleans, and loses checking for int params, etc.
>> >
>> >I liked Americo's approach; I've combined the two approaches below.
>> >
>> >Since I'm going away, can Andrew take this?
>> >
>> >Subject: params: don't hand NULL values to param.set callbacks.
>> >
>> >An audit by Dongdong Deng revealed that most driver-author-written param
>> >calls don't handle val == NULL (which happens when parameters are specified
>> >with no =, eg "foo" instead of "foo=1").
>> >
>> >The only real case to use this is boolean, so handle it specially for that
>> >case and remove a source of bugs for everyone else as suggested by Americo.
>> >
>> >Signed-off-by: Rusty Russell <[email protected]>
>> >Cc: Dongdong Deng <[email protected]>
>> >Cc: Américo Wang <[email protected]>
>> >
>> >diff --git a/kernel/params.c b/kernel/params.c
>> >--- a/kernel/params.c
>> >+++ b/kernel/params.c
>> >@@ -59,6 +59,9 @@ static int parse_one(char *param,
>> > /* Find parameter */
>> > for (i = 0; i < num_params; i++) {
>> > if (parameq(param, params[i].name)) {
>> >+ /* Noone handled NULL, so do it here. */
>> >+ if (!val && params[i].set != param_set_bool)
>> >+ return -EINVAL;
>>
>> Sorry, after rethinking about this, I think it might be wrong.
>>
>> With this patch, when I use non-standard bool functions, I will not
>> have a chance to use '!val' which should be valid for all bool
>> functions. Or am I missing something?
>
> Sure, at that point we'd need something more sophisticated. But to
> fix this properly we want a flags word, and thus something like this
> which I worked on earlier:
>
> http://ozlabs.org/~rusty/kernel/rr-latest/param:param_ops.patch
>
Thanks, Rusty!
I love that patch, but since 2.6.33 is already out, can we try to get it
merged for 2.6.34?