* [PATCH] i2c: strncpy does not null terminate string
@ 2009-07-17 13:03 Roel Kluin
[not found] ` <4A60769C.9010707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 4+ messages in thread
From: Roel Kluin @ 2009-07-17 13:03 UTC (permalink / raw)
To: khali-PUYAD+kWke1g9hUCZPvPmw, ben-linux-elnMNo+KYs3YtjvyW6yDsg,
linux-i2c-u79uwXL29TY76Z2rM5mHXA, Andrew Morton
With `sizeof(string) - 1` strncpy() will null terminate the string.
Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
To test this:
#include <stdio.h>
#include <string.h>
char a[10];
char b[10];
int main()
{
const char* str = "0123456789012";
strncpy(a, str, sizeof(a));
strncpy(b, str, sizeof(b) - 1);
printf("String a was %s, b was %s\n", a, b);
return 0;
}
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index fdd8327..bede75d 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -879,7 +879,7 @@ omap_i2c_probe(struct platform_device *pdev)
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_HWMON;
- strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
+ strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name) - 1);
adap->algo = &omap_i2c_algo;
adap->dev.parent = &pdev->dev;
^ permalink raw reply related [flat|nested] 4+ messages in thread[parent not found: <4A60769C.9010707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]
* Re: [PATCH] i2c: strncpy does not null terminate string [not found] ` <4A60769C.9010707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> @ 2009-07-17 13:06 ` Jean Delvare [not found] ` <20090717150624.4a0636f7-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org> 2009-07-17 13:24 ` Roel Kluin 1 sibling, 1 reply; 4+ messages in thread From: Jean Delvare @ 2009-07-17 13:06 UTC (permalink / raw) To: Roel Kluin Cc: ben-linux-elnMNo+KYs3YtjvyW6yDsg, linux-i2c-u79uwXL29TY76Z2rM5mHXA, Andrew Morton On Fri, 17 Jul 2009 15:03:24 +0200, Roel Kluin wrote: > With `sizeof(string) - 1` strncpy() will null terminate the string. > > Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> > --- > To test this: > > #include <stdio.h> > #include <string.h> > > char a[10]; > char b[10]; > > int main() > { > const char* str = "0123456789012"; > strncpy(a, str, sizeof(a)); > strncpy(b, str, sizeof(b) - 1); > printf("String a was %s, b was %s\n", a, b); > > return 0; > } > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index fdd8327..bede75d 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -879,7 +879,7 @@ omap_i2c_probe(struct platform_device *pdev) > i2c_set_adapdata(adap, dev); > adap->owner = THIS_MODULE; > adap->class = I2C_CLASS_HWMON; > - strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); > + strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name) - 1); > adap->algo = &omap_i2c_algo; > adap->dev.parent = &pdev->dev; Nack, please just use strlcpy() instead. IMHO strncpy() should be banned from the kernel. -- Jean Delvare ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <20090717150624.4a0636f7-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>]
* Re: [PATCH] i2c: strncpy does not null terminate string [not found] ` <20090717150624.4a0636f7-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org> @ 2009-07-17 13:13 ` Jean Delvare 0 siblings, 0 replies; 4+ messages in thread From: Jean Delvare @ 2009-07-17 13:13 UTC (permalink / raw) To: Roel Kluin Cc: ben-linux-elnMNo+KYs3YtjvyW6yDsg, linux-i2c-u79uwXL29TY76Z2rM5mHXA, Andrew Morton Oh, BTW... On Fri, 17 Jul 2009 15:06:24 +0200, Jean Delvare wrote: > On Fri, 17 Jul 2009 15:03:24 +0200, Roel Kluin wrote: > > With `sizeof(string) - 1` strncpy() will null terminate the string. > > > > Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> > > --- > > To test this: > > > > #include <stdio.h> > > #include <string.h> > > > > char a[10]; > > char b[10]; > > > > int main() > > { > > const char* str = "0123456789012"; > > strncpy(a, str, sizeof(a)); > > strncpy(b, str, sizeof(b) - 1); > > printf("String a was %s, b was %s\n", a, b); > > > > return 0; > > } You can't compare user-space code and kernel code, as libc implementations can differ. For example, snprintf() in user-space may not NULL-terminate the string while the kernel implementation always does. > > > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > > index fdd8327..bede75d 100644 > > --- a/drivers/i2c/busses/i2c-omap.c > > +++ b/drivers/i2c/busses/i2c-omap.c > > @@ -879,7 +879,7 @@ omap_i2c_probe(struct platform_device *pdev) > > i2c_set_adapdata(adap, dev); > > adap->owner = THIS_MODULE; > > adap->class = I2C_CLASS_HWMON; > > - strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); > > + strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name) - 1); > > adap->algo = &omap_i2c_algo; > > adap->dev.parent = &pdev->dev; > > Nack, please just use strlcpy() instead. > > IMHO strncpy() should be banned from the kernel. > -- Jean Delvare ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] i2c: strncpy does not null terminate string [not found] ` <4A60769C.9010707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2009-07-17 13:06 ` Jean Delvare @ 2009-07-17 13:24 ` Roel Kluin 1 sibling, 0 replies; 4+ messages in thread From: Roel Kluin @ 2009-07-17 13:24 UTC (permalink / raw) Cc: khali-PUYAD+kWke1g9hUCZPvPmw, ben-linux-elnMNo+KYs3YtjvyW6yDsg, linux-i2c-u79uwXL29TY76Z2rM5mHXA, Andrew Morton strlcpy() will always null terminate the string. Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> --- diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index fdd8327..f2b82ee 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -879,7 +879,7 @@ omap_i2c_probe(struct platform_device *pdev) i2c_set_adapdata(adap, dev); adap->owner = THIS_MODULE; adap->class = I2C_CLASS_HWMON; - strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); + strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); adap->algo = &omap_i2c_algo; adap->dev.parent = &pdev->dev; ^ permalink raw reply related [flat|nested] 4+ messages in thread
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2009-07-17 13:03 [PATCH] i2c: strncpy does not null terminate string Roel Kluin
[not found] ` <4A60769C.9010707-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2009-07-17 13:06 ` Jean Delvare
[not found] ` <20090717150624.4a0636f7-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>
2009-07-17 13:13 ` Jean Delvare
2009-07-17 13:24 ` Roel Kluin
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