| Message ID | 1444235714-24365-1-git-send-email-srinivas.kandagatla@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Wed, Oct 07, 2015 at 05:35:14PM +0100, Srinivas Kandagatla wrote: > As required by many providers like at24/at25/mxs-ocotp/qfprom, which would > want to allow root-only to read/write the nvmem content. > So making the defaults to be root-only access which can prevent normal > users from reading the nvmem data. > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > --- > drivers/nvmem/core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c > index 6fd4e5a..4d2e476 100644 > --- a/drivers/nvmem/core.c > +++ b/drivers/nvmem/core.c > @@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, > static struct bin_attribute bin_attr_rw_nvmem = { > .attr = { > .name = "nvmem", > - .mode = S_IWUSR | S_IRUGO, > + .mode = S_IWUSR | S_IRUSR, > }, > .read = bin_attr_nvmem_read, > .write = bin_attr_nvmem_write, > @@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { > static struct bin_attribute bin_attr_ro_nvmem = { > .attr = { > .name = "nvmem", > - .mode = S_IRUGO, > + .mode = S_IRUSR, > }, > .read = bin_attr_nvmem_read, > }; How about using BIN_ATTR_RO() and friends instead, that way I _know_ you got the permissions correct as it's impossible to get them wrong by using those macros. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 07/10/15 17:50, Greg KH wrote: > On Wed, Oct 07, 2015 at 05:35:14PM +0100, Srinivas Kandagatla wrote: >> As required by many providers like at24/at25/mxs-ocotp/qfprom, which would >> want to allow root-only to read/write the nvmem content. >> So making the defaults to be root-only access which can prevent normal >> users from reading the nvmem data. >> >> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >> --- >> drivers/nvmem/core.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c >> index 6fd4e5a..4d2e476 100644 >> --- a/drivers/nvmem/core.c >> +++ b/drivers/nvmem/core.c >> @@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, >> static struct bin_attribute bin_attr_rw_nvmem = { >> .attr = { >> .name = "nvmem", >> - .mode = S_IWUSR | S_IRUGO, >> + .mode = S_IWUSR | S_IRUSR, >> }, >> .read = bin_attr_nvmem_read, >> .write = bin_attr_nvmem_write, >> @@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { >> static struct bin_attribute bin_attr_ro_nvmem = { >> .attr = { >> .name = "nvmem", >> - .mode = S_IRUGO, >> + .mode = S_IRUSR, >> }, >> .read = bin_attr_nvmem_read, >> }; > > How about using BIN_ATTR_RO() and friends instead, that way I _know_ you > got the permissions correct as it's impossible to get them wrong by > using those macros. Yes, that sounds good, but there are no macros for just "S_IRUSR" or "(S_IWUSR | S_IRUSR)" in ./include/linux/sysfs.h --srini > > thanks, > > greg k-h > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Wed, Oct 07, 2015 at 06:01:03PM +0100, Srinivas Kandagatla wrote: > > > On 07/10/15 17:50, Greg KH wrote: > >On Wed, Oct 07, 2015 at 05:35:14PM +0100, Srinivas Kandagatla wrote: > >>As required by many providers like at24/at25/mxs-ocotp/qfprom, which would > >>want to allow root-only to read/write the nvmem content. > >>So making the defaults to be root-only access which can prevent normal > >>users from reading the nvmem data. > >> > >>Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > >>--- > >> drivers/nvmem/core.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >>diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c > >>index 6fd4e5a..4d2e476 100644 > >>--- a/drivers/nvmem/core.c > >>+++ b/drivers/nvmem/core.c > >>@@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, > >> static struct bin_attribute bin_attr_rw_nvmem = { > >> .attr = { > >> .name = "nvmem", > >>- .mode = S_IWUSR | S_IRUGO, > >>+ .mode = S_IWUSR | S_IRUSR, > >> }, > >> .read = bin_attr_nvmem_read, > >> .write = bin_attr_nvmem_write, > >>@@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { > >> static struct bin_attribute bin_attr_ro_nvmem = { > >> .attr = { > >> .name = "nvmem", > >>- .mode = S_IRUGO, > >>+ .mode = S_IRUSR, > >> }, > >> .read = bin_attr_nvmem_read, > >> }; > > > >How about using BIN_ATTR_RO() and friends instead, that way I _know_ you > >got the permissions correct as it's impossible to get them wrong by > >using those macros. > Yes, that sounds good, but there are no macros for just "S_IRUSR" or > "(S_IWUSR | S_IRUSR)" in ./include/linux/sysfs.h Then that means you are trying to do something "odd" and you shouldn't be doing that :) Use the standard attribute permissions (RO, RW), as those are the "safest" and what you really want to be using here, as you already are. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 07/10/15 18:12, Greg KH wrote: > On Wed, Oct 07, 2015 at 06:01:03PM +0100, Srinivas Kandagatla wrote: >> >> >> On 07/10/15 17:50, Greg KH wrote: >>> On Wed, Oct 07, 2015 at 05:35:14PM +0100, Srinivas Kandagatla wrote: >>>> As required by many providers like at24/at25/mxs-ocotp/qfprom, which would >>>> want to allow root-only to read/write the nvmem content. >>>> So making the defaults to be root-only access which can prevent normal >>>> users from reading the nvmem data. >>>> >>>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >>>> --- >>>> drivers/nvmem/core.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c >>>> index 6fd4e5a..4d2e476 100644 >>>> --- a/drivers/nvmem/core.c >>>> +++ b/drivers/nvmem/core.c >>>> @@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, >>>> static struct bin_attribute bin_attr_rw_nvmem = { >>>> .attr = { >>>> .name = "nvmem", >>>> - .mode = S_IWUSR | S_IRUGO, >>>> + .mode = S_IWUSR | S_IRUSR, >>>> }, >>>> .read = bin_attr_nvmem_read, >>>> .write = bin_attr_nvmem_write, >>>> @@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { >>>> static struct bin_attribute bin_attr_ro_nvmem = { >>>> .attr = { >>>> .name = "nvmem", >>>> - .mode = S_IRUGO, >>>> + .mode = S_IRUSR, >>>> }, >>>> .read = bin_attr_nvmem_read, >>>> }; >>> >>> How about using BIN_ATTR_RO() and friends instead, that way I _know_ you >>> got the permissions correct as it's impossible to get them wrong by >>> using those macros. >> Yes, that sounds good, but there are no macros for just "S_IRUSR" or >> "(S_IWUSR | S_IRUSR)" in ./include/linux/sysfs.h > > Then that means you are trying to do something "odd" and you shouldn't > be doing that :) > The requirement originally came from a discussion regarding file permissions set by at24 (drivers/mis/eeprom/at24.c) vs nvmem. at24 driver sets the permission of root-only read/write, which is different to what nvmem sets as default. So this patch was primarily make nvmem framework inline with what at24/at25 does. Other argument was regarding the content of the nvmem which could have things like keys and normal user should not be allowed read it. --srini > Use the standard attribute permissions (RO, RW), as those are the > "safest" and what you really want to be using here, as you already are. > > thanks, > > greg k-h > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Wed, Oct 07, 2015 at 06:26:02PM +0100, Srinivas Kandagatla wrote: > > > On 07/10/15 18:12, Greg KH wrote: > >On Wed, Oct 07, 2015 at 06:01:03PM +0100, Srinivas Kandagatla wrote: > >> > >> > >>On 07/10/15 17:50, Greg KH wrote: > >>>On Wed, Oct 07, 2015 at 05:35:14PM +0100, Srinivas Kandagatla wrote: > >>>>As required by many providers like at24/at25/mxs-ocotp/qfprom, which would > >>>>want to allow root-only to read/write the nvmem content. > >>>>So making the defaults to be root-only access which can prevent normal > >>>>users from reading the nvmem data. > >>>> > >>>>Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > >>>>--- > >>>> drivers/nvmem/core.c | 4 ++-- > >>>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>>> > >>>>diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c > >>>>index 6fd4e5a..4d2e476 100644 > >>>>--- a/drivers/nvmem/core.c > >>>>+++ b/drivers/nvmem/core.c > >>>>@@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, > >>>> static struct bin_attribute bin_attr_rw_nvmem = { > >>>> .attr = { > >>>> .name = "nvmem", > >>>>- .mode = S_IWUSR | S_IRUGO, > >>>>+ .mode = S_IWUSR | S_IRUSR, > >>>> }, > >>>> .read = bin_attr_nvmem_read, > >>>> .write = bin_attr_nvmem_write, > >>>>@@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { > >>>> static struct bin_attribute bin_attr_ro_nvmem = { > >>>> .attr = { > >>>> .name = "nvmem", > >>>>- .mode = S_IRUGO, > >>>>+ .mode = S_IRUSR, > >>>> }, > >>>> .read = bin_attr_nvmem_read, > >>>> }; > >>> > >>>How about using BIN_ATTR_RO() and friends instead, that way I _know_ you > >>>got the permissions correct as it's impossible to get them wrong by > >>>using those macros. > >>Yes, that sounds good, but there are no macros for just "S_IRUSR" or > >>"(S_IWUSR | S_IRUSR)" in ./include/linux/sysfs.h > > > >Then that means you are trying to do something "odd" and you shouldn't > >be doing that :) > > > The requirement originally came from a discussion regarding file permissions > set by at24 (drivers/mis/eeprom/at24.c) vs nvmem. > > at24 driver sets the permission of root-only read/write, which is different > to what nvmem sets as default. > > So this patch was primarily make nvmem framework inline with what at24/at25 > does. Doesn't sound like a good idea, take this time to fix that lapse in security :) greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 6fd4e5a..4d2e476 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -112,7 +112,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, static struct bin_attribute bin_attr_rw_nvmem = { .attr = { .name = "nvmem", - .mode = S_IWUSR | S_IRUGO, + .mode = S_IWUSR | S_IRUSR, }, .read = bin_attr_nvmem_read, .write = bin_attr_nvmem_write, @@ -136,7 +136,7 @@ static const struct attribute_group *nvmem_rw_dev_groups[] = { static struct bin_attribute bin_attr_ro_nvmem = { .attr = { .name = "nvmem", - .mode = S_IRUGO, + .mode = S_IRUSR, }, .read = bin_attr_nvmem_read, };
As required by many providers like at24/at25/mxs-ocotp/qfprom, which would want to allow root-only to read/write the nvmem content. So making the defaults to be root-only access which can prevent normal users from reading the nvmem data. Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> --- drivers/nvmem/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)