| Message ID | 1477413715-22894-9-git-send-email-kieran@bingham.xyz |
|---|---|
| State | Superseded |
| Headers | show |
On Tue, 25 Oct 2016, Kieran Bingham wrote: > If a user provides a shortened string to match a device to the sysfs i2c > interface it will match on the first string that contains that string > prefix. > > for example: > echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device > > will match as3711, as3722, and ak8975 incorrectly. > > Signed-off-by: Kieran Bingham <kieran@bingham.xyz> Acked-by: Lee Jones <lee.jones@linaro.org> > --- > drivers/i2c/i2c-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 01bce56f733a..50c9cfdb87b7 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, > else > name++; > > - if (!strncasecmp(client->name, name, strlen(client->name))) > + if (!strncasecmp(client->name, name, strlen(name))) > return matches; > } >
On 2016-10-26 10:53, Lee Jones wrote: > On Tue, 25 Oct 2016, Kieran Bingham wrote: > >> If a user provides a shortened string to match a device to the sysfs i2c >> interface it will match on the first string that contains that string >> prefix. >> >> for example: >> echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device >> >> will match as3711, as3722, and ak8975 incorrectly. >> >> Signed-off-by: Kieran Bingham <kieran@bingham.xyz> > > Acked-by: Lee Jones <lee.jones@linaro.org> > >> --- >> drivers/i2c/i2c-core.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >> index 01bce56f733a..50c9cfdb87b7 100644 >> --- a/drivers/i2c/i2c-core.c >> +++ b/drivers/i2c/i2c-core.c >> @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, >> else >> name++; >> >> - if (!strncasecmp(client->name, name, strlen(client->name))) >> + if (!strncasecmp(client->name, name, strlen(name))) >> return matches; >> } >> > Is that really so much better? With this patch echo as3711CRAP 0x68 > /sys/... will match as3711. What if there is some as37112 driver that is the real target? Cheers, Peter -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Peter, Thanks for your review On 31/10/16 13:55, Peter Rosin wrote: > On 2016-10-26 10:53, Lee Jones wrote: >> On Tue, 25 Oct 2016, Kieran Bingham wrote: >> >>> If a user provides a shortened string to match a device to the sysfs i2c >>> interface it will match on the first string that contains that string >>> prefix. >>> >>> for example: >>> echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device >>> >>> will match as3711, as3722, and ak8975 incorrectly. >>> >>> Signed-off-by: Kieran Bingham <kieran@bingham.xyz> >> >> Acked-by: Lee Jones <lee.jones@linaro.org> >> >>> --- >>> drivers/i2c/i2c-core.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >>> index 01bce56f733a..50c9cfdb87b7 100644 >>> --- a/drivers/i2c/i2c-core.c >>> +++ b/drivers/i2c/i2c-core.c >>> @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, >>> else >>> name++; >>> >>> - if (!strncasecmp(client->name, name, strlen(client->name))) >>> + if (!strncasecmp(client->name, name, strlen(name))) >>> return matches; >>> } >>> >> > > Is that really so much better? My original thought was that it verifies 'more' of the userspace input. but... > With this patch > echo as3711CRAP 0x68 > /sys/... > will match as3711. > > What if there is some as37112 driver that is the real target? You're right - It looks like the only way to do this correctly is to match the strncasecmp and the strlen of both strings. So really we should be using sysfs_streq(). The only limitation there is that this original code was performing a case-insensitive compare. Lee - Where did the requirement for case insensitive matching come from in your original code. Is it expected to be case-insensitive from the I2C sysfs interface? or are dt-nodes expected to be case-sensitive? Does anyone see reason that this shouldn't be using sysfs_streq()? or do we need a sysfs_strcaseeq()... > Cheers, > Peter >
On Mon, 31 Oct 2016, Kieran Bingham wrote: > On 31/10/16 13:55, Peter Rosin wrote: > > On 2016-10-26 10:53, Lee Jones wrote: > >> On Tue, 25 Oct 2016, Kieran Bingham wrote: > >> > >>> If a user provides a shortened string to match a device to the sysfs i2c > >>> interface it will match on the first string that contains that string > >>> prefix. > >>> > >>> for example: > >>> echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device > >>> > >>> will match as3711, as3722, and ak8975 incorrectly. > >>> > >>> Signed-off-by: Kieran Bingham <kieran@bingham.xyz> > >> > >> Acked-by: Lee Jones <lee.jones@linaro.org> > >> > >>> --- > >>> drivers/i2c/i2c-core.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > >>> index 01bce56f733a..50c9cfdb87b7 100644 > >>> --- a/drivers/i2c/i2c-core.c > >>> +++ b/drivers/i2c/i2c-core.c > >>> @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, > >>> else > >>> name++; > >>> > >>> - if (!strncasecmp(client->name, name, strlen(client->name))) > >>> + if (!strncasecmp(client->name, name, strlen(name))) > >>> return matches; > >>> } > >>> > >> > > > > Is that really so much better? > > My original thought was that it verifies 'more' of the userspace input. > but... > > > With this patch > > echo as3711CRAP 0x68 > /sys/... > > will match as3711. > > > > What if there is some as37112 driver that is the real target? > > You're right - It looks like the only way to do this correctly is to > match the strncasecmp and the strlen of both strings. > > So really we should be using sysfs_streq(). The only limitation there is > that this original code was performing a case-insensitive compare. > > Lee - Where did the requirement for case insensitive matching come from > in your original code. Is it expected to be case-insensitive from the > I2C sysfs interface? or are dt-nodes expected to be case-sensitive? Compatible strings are always lower-case. > Does anyone see reason that this shouldn't be using sysfs_streq()? or do > we need a sysfs_strcaseeq()... ... but I don't see an issue with not being case sensitive. Certainly if it makes the logic easier/more consistent.
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 01bce56f733a..50c9cfdb87b7 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, else name++; - if (!strncasecmp(client->name, name, strlen(client->name))) + if (!strncasecmp(client->name, name, strlen(name))) return matches; }
If a user provides a shortened string to match a device to the sysfs i2c interface it will match on the first string that contains that string prefix. for example: echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device will match as3711, as3722, and ak8975 incorrectly. Signed-off-by: Kieran Bingham <kieran@bingham.xyz> --- drivers/i2c/i2c-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)