Sometimes the input from user may cause an unexpected result.
for example, echo "1-3," > /proc/irq/<xxx>/smp_affinity_list.
The correct result should be 1-3, however we got 0-4.
To avoid this issue, we check if there is a ready digit.
If no valid digit is set, we just continue to the next parse.
Signed-off-by: Pan Xinhui <[email protected]>
---
lib/bitmap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 64c0926..3c489c1 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -561,6 +561,8 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
return -EINVAL;
if (b >= nmaskbits)
return -ERANGE;
+ if (unlikely(exp_digit))
+ continue;
while (a <= b) {
set_bit(a, maskp);
a++;
--
1.9.1
On Sat, 27 Jun 2015 14:36:18 +0800 Pan Xinhui <[email protected]> wrote:
> Sometimes the input from user may cause an unexpected result.
>
> for example, echo "1-3," > /proc/irq/<xxx>/smp_affinity_list.
> The correct result should be 1-3, however we got 0-4.
>
> To avoid this issue, we check if there is a ready digit.
> If no valid digit is set, we just continue to the next parse.
>
> Signed-off-by: Pan Xinhui <[email protected]>
> ---
> lib/bitmap.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 64c0926..3c489c1 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -561,6 +561,8 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
> return -EINVAL;
> if (b >= nmaskbits)
> return -ERANGE;
> + if (unlikely(exp_digit))
> + continue;
> while (a <= b) {
> set_bit(a, maskp);
> a++;
This bug might have been fixed by 2528a8b8f457d7 ("__bitmap_parselist:
fix bug in empty string handling"), below. Please check?
commit 2528a8b8f457d7432552d0e2b6f0f4046bb702f4
Author: Chris Metcalf <[email protected]>
AuthorDate: Thu Jun 25 15:02:08 2015 -0700
Commit: Linus Torvalds <[email protected]>
CommitDate: Thu Jun 25 17:00:40 2015 -0700
__bitmap_parselist: fix bug in empty string handling
bitmap_parselist("", &mask, nmaskbits) will erroneously set bit zero in
the mask. The same bug is visible in cpumask_parselist() since it is
layered on top of the bitmask code, e.g. if you boot with "isolcpus=",
you will actually end up with cpu zero isolated.
The bug was introduced in commit 4b060420a596 ("bitmap, irq: add
smp_affinity_list interface to /proc/irq") when bitmap_parselist() was
generalized to support userspace as well as kernelspace.
Fixes: 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq")
Signed-off-by: Chris Metcalf <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 64c0926..40162f8 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -506,12 +506,12 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
unsigned a, b;
int c, old_c, totaldigits;
const char __user __force *ubuf = (const char __user __force *)buf;
- int exp_digit, in_range;
+ int at_start, in_range;
totaldigits = c = 0;
bitmap_zero(maskp, nmaskbits);
do {
- exp_digit = 1;
+ at_start = 1;
in_range = 0;
a = b = 0;
@@ -540,11 +540,10 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
break;
if (c == '-') {
- if (exp_digit || in_range)
+ if (at_start || in_range)
return -EINVAL;
b = 0;
in_range = 1;
- exp_digit = 1;
continue;
}
@@ -554,16 +553,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
b = b * 10 + (c - '0');
if (!in_range)
a = b;
- exp_digit = 0;
+ at_start = 0;
totaldigits++;
}
if (!(a <= b))
return -EINVAL;
if (b >= nmaskbits)
return -ERANGE;
- while (a <= b) {
- set_bit(a, maskp);
- a++;
+ if (!at_start) {
+ while (a <= b) {
+ set_bit(a, maskp);
+ a++;
+ }
}
} while (buflen && c == ',');
return 0;
hi, Andrew
thanks for you kind reply :)
On 2015年07月10日 06:57, Andrew Morton wrote:
> On Sat, 27 Jun 2015 14:36:18 +0800 Pan Xinhui <[email protected]> wrote:
>
>> Sometimes the input from user may cause an unexpected result.
>>
>> for example, echo "1-3," > /proc/irq/<xxx>/smp_affinity_list.
>> The correct result should be 1-3, however we got 0-4.
>>
>> To avoid this issue, we check if there is a ready digit.
>> If no valid digit is set, we just continue to the next parse.
>>
>> Signed-off-by: Pan Xinhui <[email protected]>
>> ---
>> lib/bitmap.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/lib/bitmap.c b/lib/bitmap.c
>> index 64c0926..3c489c1 100644
>> --- a/lib/bitmap.c
>> +++ b/lib/bitmap.c
>> @@ -561,6 +561,8 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
>> return -EINVAL;
>> if (b >= nmaskbits)
>> return -ERANGE;
>> + if (unlikely(exp_digit))
>> + continue;
>> while (a <= b) {
>> set_bit(a, maskp);
>> a++;
>
> This bug might have been fixed by 2528a8b8f457d7 ("__bitmap_parselist:
> fix bug in empty string handling"), below. Please check?
>
>
Yes, I noticed it after I sent this patch out. Sorry for not syncing the upstream codes.
I am very happy that you reviewed my patch :)
I send out other three patches to make current codes stronger :)
they are
[PATCH 1/3] lib/bitmap.c: correct a code style and do some optimization in __bitmap_parse
[PATCH 2/3] lib/bitmap.c: fix a special string handling bug in __bitmap_parselist
[PATCH 3/3] lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or tail
Of course I have verified/test them :)
They have minor codes change.
thanks
xinhui
> commit 2528a8b8f457d7432552d0e2b6f0f4046bb702f4
> Author: Chris Metcalf <[email protected]>
> AuthorDate: Thu Jun 25 15:02:08 2015 -0700
> Commit: Linus Torvalds <[email protected]>
> CommitDate: Thu Jun 25 17:00:40 2015 -0700
>
> __bitmap_parselist: fix bug in empty string handling
>
> bitmap_parselist("", &mask, nmaskbits) will erroneously set bit zero in
> the mask. The same bug is visible in cpumask_parselist() since it is
> layered on top of the bitmask code, e.g. if you boot with "isolcpus=",
> you will actually end up with cpu zero isolated.
>
> The bug was introduced in commit 4b060420a596 ("bitmap, irq: add
> smp_affinity_list interface to /proc/irq") when bitmap_parselist() was
> generalized to support userspace as well as kernelspace.
>
> Fixes: 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq")
> Signed-off-by: Chris Metcalf <[email protected]>
> Cc: Rasmus Villemoes <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> Signed-off-by: Linus Torvalds <[email protected]>
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 64c0926..40162f8 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -506,12 +506,12 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
> unsigned a, b;
> int c, old_c, totaldigits;
> const char __user __force *ubuf = (const char __user __force *)buf;
> - int exp_digit, in_range;
> + int at_start, in_range;
>
> totaldigits = c = 0;
> bitmap_zero(maskp, nmaskbits);
> do {
> - exp_digit = 1;
> + at_start = 1;
> in_range = 0;
> a = b = 0;
>
> @@ -540,11 +540,10 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
> break;
>
> if (c == '-') {
> - if (exp_digit || in_range)
> + if (at_start || in_range)
> return -EINVAL;
> b = 0;
> in_range = 1;
> - exp_digit = 1;
> continue;
> }
>
> @@ -554,16 +553,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
> b = b * 10 + (c - '0');
> if (!in_range)
> a = b;
> - exp_digit = 0;
> + at_start = 0;
> totaldigits++;
> }
> if (!(a <= b))
> return -EINVAL;
> if (b >= nmaskbits)
> return -ERANGE;
> - while (a <= b) {
> - set_bit(a, maskp);
> - a++;
> + if (!at_start) {
> + while (a <= b) {
> + set_bit(a, maskp);
> + a++;
> + }
> }
> } while (buflen && c == ',');
> return 0;
>