Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
On Thu, Jan 15, 2015 at 5:02 PM, Masami Hiramatsu
wrote:
> (2015/01/16 0:22), Andy Lutomirski wrote:
>> On Jan 15, 2015 4:37 AM, "Masami Hiramatsu"
>> wrote:
>>>
>>> (2015/01/14 6:49), Andy Lutomirski wrote:
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
>>>
>>> Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
>>
>> I don't want to do that for 3.19. It's kind of late.
>>
>>>
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
instruction decoder
Signed-off-by: Andy Lutomirski
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
x86_64)
{
+ /*
+ * Instructions longer than 15 bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len > 15)
+ buf_len = 15;
+
>>>
>>> Without changing the MAX_INSN_SIZE, this looks very odd, since all other
>>> code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
>>> except here.
>>
>> I thought this was your suggestion. Did I misunderstand?
>
> Yes, what I meant about "15" was the the "15" in the comment.
> So
>
> + /*
> + * Instructions longer than MAX_INSN_SIZE bytes are invalid even if the
> + * input buffer is long enough to hold them.
> + */
> + if (buf_len > MAX_INSN_SIZE)
> + buf_len = MAX_INSN_SIZE;
>
> is acceptable.
>
>> If you think the current code is okay for 3.19, I can fold the two
>> patches together and send for 3.20.
>
> If it does really cause a bug or a real problem, it must fix asap.
> If not, I'd like to fix this issue with changing MAX_INSN_SIZE to 15.
>
Since this has waited for quite a while and there's no known urgent
problem, I'll just send a combined patch.
--Andy
> Thank you,
>
> --
> Masami HIRAMATSU
> Software Platform Research Dept. Linux Technology Research Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu...@hitachi.com
>
>
--
Andy Lutomirski
AMA Capital Management, LLC
--
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Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
On Thu, Jan 15, 2015 at 5:02 PM, Masami Hiramatsu
masami.hiramatsu...@hitachi.com wrote:
(2015/01/16 0:22), Andy Lutomirski wrote:
On Jan 15, 2015 4:37 AM, Masami Hiramatsu
masami.hiramatsu...@hitachi.com wrote:
(2015/01/14 6:49), Andy Lutomirski wrote:
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
I don't want to do that for 3.19. It's kind of late.
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
instruction decoder
Signed-off-by: Andy Lutomirski l...@amacapital.net
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
x86_64)
{
+ /*
+ * Instructions longer than 15 bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len 15)
+ buf_len = 15;
+
Without changing the MAX_INSN_SIZE, this looks very odd, since all other
code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
except here.
I thought this was your suggestion. Did I misunderstand?
Yes, what I meant about 15 was the the 15 in the comment.
So
+ /*
+ * Instructions longer than MAX_INSN_SIZE bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len MAX_INSN_SIZE)
+ buf_len = MAX_INSN_SIZE;
is acceptable.
If you think the current code is okay for 3.19, I can fold the two
patches together and send for 3.20.
If it does really cause a bug or a real problem, it must fix asap.
If not, I'd like to fix this issue with changing MAX_INSN_SIZE to 15.
Since this has waited for quite a while and there's no known urgent
problem, I'll just send a combined patch.
--Andy
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
Andy Lutomirski
AMA Capital Management, LLC
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
(2015/01/16 0:22), Andy Lutomirski wrote:
> On Jan 15, 2015 4:37 AM, "Masami Hiramatsu"
> wrote:
>>
>> (2015/01/14 6:49), Andy Lutomirski wrote:
>>> x86 instructions cannot exceed 15 bytes, and the instruction decoder
>>> should enforce that. Prior to 6ba48ff46f76, the instruction length
>>> limit was implicitly set to 16, which was an approximation of 15,
>>> but there is currently no limit at all.
>>>
>>> Fix the decoder to reject instructions that exceed 15 bytes.
>>> A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
>>
>> Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
>
> I don't want to do that for 3.19. It's kind of late.
>
>>
>>> Other than potentially confusing some of the decoder sanity checks,
>>> I'm not aware of any actual problems that omitting this check would
>>> cause.
>>>
>>> Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
>>> instruction decoder
>>> Signed-off-by: Andy Lutomirski
>>> ---
>>> arch/x86/lib/insn.c | 7 +++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
>>> index 2480978b31cc..7b80745d2c5a 100644
>>> --- a/arch/x86/lib/insn.c
>>> +++ b/arch/x86/lib/insn.c
>>> @@ -52,6 +52,13 @@
>>> */
>>> void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
>>> x86_64)
>>> {
>>> + /*
>>> + * Instructions longer than 15 bytes are invalid even if the
>>> + * input buffer is long enough to hold them.
>>> + */
>>> + if (buf_len > 15)
>>> + buf_len = 15;
>>> +
>>
>> Without changing the MAX_INSN_SIZE, this looks very odd, since all other
>> code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
>> except here.
>
> I thought this was your suggestion. Did I misunderstand?
Yes, what I meant about "15" was the the "15" in the comment.
So
+ /*
+ * Instructions longer than MAX_INSN_SIZE bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len > MAX_INSN_SIZE)
+ buf_len = MAX_INSN_SIZE;
is acceptable.
> If you think the current code is okay for 3.19, I can fold the two
> patches together and send for 3.20.
If it does really cause a bug or a real problem, it must fix asap.
If not, I'd like to fix this issue with changing MAX_INSN_SIZE to 15.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
On Jan 15, 2015 4:37 AM, "Masami Hiramatsu"
wrote:
>
> (2015/01/14 6:49), Andy Lutomirski wrote:
> > x86 instructions cannot exceed 15 bytes, and the instruction decoder
> > should enforce that. Prior to 6ba48ff46f76, the instruction length
> > limit was implicitly set to 16, which was an approximation of 15,
> > but there is currently no limit at all.
> >
> > Fix the decoder to reject instructions that exceed 15 bytes.
> > A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
>
> Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
I don't want to do that for 3.19. It's kind of late.
>
> > Other than potentially confusing some of the decoder sanity checks,
> > I'm not aware of any actual problems that omitting this check would
> > cause.
> >
> > Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
> > instruction decoder
> > Signed-off-by: Andy Lutomirski
> > ---
> > arch/x86/lib/insn.c | 7 +++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
> > index 2480978b31cc..7b80745d2c5a 100644
> > --- a/arch/x86/lib/insn.c
> > +++ b/arch/x86/lib/insn.c
> > @@ -52,6 +52,13 @@
> > */
> > void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
> > x86_64)
> > {
> > + /*
> > + * Instructions longer than 15 bytes are invalid even if the
> > + * input buffer is long enough to hold them.
> > + */
> > + if (buf_len > 15)
> > + buf_len = 15;
> > +
>
> Without changing the MAX_INSN_SIZE, this looks very odd, since all other
> code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
> except here.
I thought this was your suggestion. Did I misunderstand?
If you think the current code is okay for 3.19, I can fold the two
patches together and send for 3.20.
--Andy
>
> Thank you,
>
> > memset(insn, 0, sizeof(*insn));
> > insn->kaddr = kaddr;
> > insn->end_kaddr = kaddr + buf_len;
> >
>
>
> --
> Masami HIRAMATSU
> Software Platform Research Dept. Linux Technology Research Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu...@hitachi.com
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
(2015/01/14 6:49), Andy Lutomirski wrote:
> x86 instructions cannot exceed 15 bytes, and the instruction decoder
> should enforce that. Prior to 6ba48ff46f76, the instruction length
> limit was implicitly set to 16, which was an approximation of 15,
> but there is currently no limit at all.
>
> Fix the decoder to reject instructions that exceed 15 bytes.
> A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
> Other than potentially confusing some of the decoder sanity checks,
> I'm not aware of any actual problems that omitting this check would
> cause.
>
> Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
> instruction decoder
> Signed-off-by: Andy Lutomirski
> ---
> arch/x86/lib/insn.c | 7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
> index 2480978b31cc..7b80745d2c5a 100644
> --- a/arch/x86/lib/insn.c
> +++ b/arch/x86/lib/insn.c
> @@ -52,6 +52,13 @@
> */
> void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64)
> {
> + /*
> + * Instructions longer than 15 bytes are invalid even if the
> + * input buffer is long enough to hold them.
> + */
> + if (buf_len > 15)
> + buf_len = 15;
> +
Without changing the MAX_INSN_SIZE, this looks very odd, since all other
code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
except here.
Thank you,
> memset(insn, 0, sizeof(*insn));
> insn->kaddr = kaddr;
> insn->end_kaddr = kaddr + buf_len;
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
On Jan 15, 2015 4:37 AM, Masami Hiramatsu
masami.hiramatsu...@hitachi.com wrote:
(2015/01/14 6:49), Andy Lutomirski wrote:
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
I don't want to do that for 3.19. It's kind of late.
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
instruction decoder
Signed-off-by: Andy Lutomirski l...@amacapital.net
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
x86_64)
{
+ /*
+ * Instructions longer than 15 bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len 15)
+ buf_len = 15;
+
Without changing the MAX_INSN_SIZE, this looks very odd, since all other
code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
except here.
I thought this was your suggestion. Did I misunderstand?
If you think the current code is okay for 3.19, I can fold the two
patches together and send for 3.20.
--Andy
Thank you,
memset(insn, 0, sizeof(*insn));
insn-kaddr = kaddr;
insn-end_kaddr = kaddr + buf_len;
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
(2015/01/14 6:49), Andy Lutomirski wrote:
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
instruction decoder
Signed-off-by: Andy Lutomirski l...@amacapital.net
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64)
{
+ /*
+ * Instructions longer than 15 bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len 15)
+ buf_len = 15;
+
Without changing the MAX_INSN_SIZE, this looks very odd, since all other
code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
except here.
Thank you,
memset(insn, 0, sizeof(*insn));
insn-kaddr = kaddr;
insn-end_kaddr = kaddr + buf_len;
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
(2015/01/16 0:22), Andy Lutomirski wrote:
On Jan 15, 2015 4:37 AM, Masami Hiramatsu
masami.hiramatsu...@hitachi.com wrote:
(2015/01/14 6:49), Andy Lutomirski wrote:
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Hmm, is there any problem to just change MAX_INSN_SIZE to 15?
I don't want to do that for 3.19. It's kind of late.
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in
instruction decoder
Signed-off-by: Andy Lutomirski l...@amacapital.net
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int
x86_64)
{
+ /*
+ * Instructions longer than 15 bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len 15)
+ buf_len = 15;
+
Without changing the MAX_INSN_SIZE, this looks very odd, since all other
code suppose that the max length of an instruction is 16 (MAX_INSN_SIZE)
except here.
I thought this was your suggestion. Did I misunderstand?
Yes, what I meant about 15 was the the 15 in the comment.
So
+ /*
+ * Instructions longer than MAX_INSN_SIZE bytes are invalid even if the
+ * input buffer is long enough to hold them.
+ */
+ if (buf_len MAX_INSN_SIZE)
+ buf_len = MAX_INSN_SIZE;
is acceptable.
If you think the current code is okay for 3.19, I can fold the two
patches together and send for 3.20.
If it does really cause a bug or a real problem, it must fix asap.
If not, I'd like to fix this issue with changing MAX_INSN_SIZE to 15.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in instruction
decoder
Signed-off-by: Andy Lutomirski
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64)
{
+ /*
+* Instructions longer than 15 bytes are invalid even if the
+* input buffer is long enough to hold them.
+*/
+ if (buf_len > 15)
+ buf_len = 15;
+
memset(insn, 0, sizeof(*insn));
insn->kaddr = kaddr;
insn->end_kaddr = kaddr + buf_len;
--
2.1.0
--
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More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.19 v4 2/2] x86: Enforce maximum instruction size in the instruction decoder
x86 instructions cannot exceed 15 bytes, and the instruction decoder
should enforce that. Prior to 6ba48ff46f76, the instruction length
limit was implicitly set to 16, which was an approximation of 15,
but there is currently no limit at all.
Fix the decoder to reject instructions that exceed 15 bytes.
A subsequent patch (targetted for 3.20) will fix MAX_INSN_SIZE.
Other than potentially confusing some of the decoder sanity checks,
I'm not aware of any actual problems that omitting this check would
cause.
Fixes: 6ba48ff46f76 x86: Remove arbitrary instruction size limit in instruction
decoder
Signed-off-by: Andy Lutomirski l...@amacapital.net
---
arch/x86/lib/insn.c | 7 +++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 2480978b31cc..7b80745d2c5a 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -52,6 +52,13 @@
*/
void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64)
{
+ /*
+* Instructions longer than 15 bytes are invalid even if the
+* input buffer is long enough to hold them.
+*/
+ if (buf_len 15)
+ buf_len = 15;
+
memset(insn, 0, sizeof(*insn));
insn-kaddr = kaddr;
insn-end_kaddr = kaddr + buf_len;
--
2.1.0
--
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