* [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings
@ 2020-02-24 6:51 pannengyuan
2020-03-03 10:14 ` Laurent Vivier
2020-03-03 10:47 ` Paolo Bonzini
0 siblings, 2 replies; 4+ messages in thread
From: pannengyuan @ 2020-02-24 6:51 UTC (permalink / raw)
To: pbonzini, rth, ehabkost
Cc: qemu-trivial, euler.robot, Pan Nengyuan, qemu-devel, zhang.zhanghailiang
From: Pan Nengyuan <pannengyuan@huawei.com>
Fix compile warnings:
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:56: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 3 [-Werror=format-truncation=]
snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
^~~~
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:41: note: directive argument in the range [-2147483648, 64]
snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
^~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:873,
from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99,
from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14:
/usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 17 and 26 bytes into a destination of size 17
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __va_arg_pack ());
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c: In function ‘hax_vcpu_devfs_string’:
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:55: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 10 [-Werror=format-truncation=]
snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
^~~~
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64]
snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
^~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64]
In file included from /usr/include/stdio.h:873,
from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99,
from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14:
/usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 21 and 39 bytes into a destination of size 21
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __va_arg_pack ());
We know that we have checked the vm_id and vcpu_id in the first(less than 0x40), it will never be truncated in snprintf().
Thus, this patch add an assertion to clear this false-positive warning.
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
---
target/i386/hax-posix.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c
index a5426a6dac..197d5bc0f9 100644
--- a/target/i386/hax-posix.c
+++ b/target/i386/hax-posix.c
@@ -121,7 +121,8 @@ static char *hax_vm_devfs_string(int vm_id)
return NULL;
}
- snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
+ int len = snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
+ assert(len < sizeof HAX_VM_DEVFS);
return name;
}
@@ -140,8 +141,9 @@ static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
return NULL;
}
- snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
- vm_id, vcpu_id);
+ int len = snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
+ vm_id, vcpu_id);
+ assert(len < sizeof HAX_VCPU_DEVFS);
return name;
}
--
2.18.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings
2020-02-24 6:51 [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings pannengyuan
@ 2020-03-03 10:14 ` Laurent Vivier
2020-03-03 10:47 ` Paolo Bonzini
1 sibling, 0 replies; 4+ messages in thread
From: Laurent Vivier @ 2020-03-03 10:14 UTC (permalink / raw)
To: pannengyuan, pbonzini, rth, ehabkost
Cc: qemu-trivial, zhang.zhanghailiang, qemu-devel, euler.robot
Le 24/02/2020 à 07:51, pannengyuan@huawei.com a écrit :
> From: Pan Nengyuan <pannengyuan@huawei.com>
>
> Fix compile warnings:
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:56: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 3 [-Werror=format-truncation=]
> snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> ^~~~
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:124:41: note: directive argument in the range [-2147483648, 64]
> snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> ^~~~~~~~~~~~~~~~~~~~
> In file included from /usr/include/stdio.h:873,
> from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99,
> from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14:
> /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 17 and 26 bytes into a destination of size 17
> return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> __bos (__s), __fmt, __va_arg_pack ());
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c: In function ‘hax_vcpu_devfs_string’:
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:55: error: ‘%02d’ directive output may be truncated writing between 2 and 11 bytes into a region of size 10 [-Werror=format-truncation=]
> snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> ^~~~
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64]
> snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> ^~~~~~~~~~~~~~~~~~~~~~~~~~
> /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:143:43: note: directive argument in the range [-2147483648, 64]
> In file included from /usr/include/stdio.h:873,
> from /mnt/sdb/qemu-new/qemu_test/qemu/include/qemu/osdep.h:99,
> from /mnt/sdb/qemu-new/qemu_test/qemu/target/i386/hax-posix.c:14:
> /usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output between 21 and 39 bytes into a destination of size 21
> return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> __bos (__s), __fmt, __va_arg_pack ());
>
> We know that we have checked the vm_id and vcpu_id in the first(less than 0x40), it will never be truncated in snprintf().
> Thus, this patch add an assertion to clear this false-positive warning.
>
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> ---
> target/i386/hax-posix.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c
> index a5426a6dac..197d5bc0f9 100644
> --- a/target/i386/hax-posix.c
> +++ b/target/i386/hax-posix.c
> @@ -121,7 +121,8 @@ static char *hax_vm_devfs_string(int vm_id)
> return NULL;
> }
>
> - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> + int len = snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> + assert(len < sizeof HAX_VM_DEVFS);
> return name;
> }
>
> @@ -140,8 +141,9 @@ static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
> return NULL;
> }
>
> - snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> - vm_id, vcpu_id);
> + int len = snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> + vm_id, vcpu_id);
> + assert(len < sizeof HAX_VCPU_DEVFS);
> return name;
> }
>
>
You should check instead that vm_id and vcpu_id are >= 0 where they are
checked to be <= MAX_VM_ID and MAX_VCPU_ID, this will avoid the overflow
of "%02d" and should remove the compile warning.
Thanks,
Laurent
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings
2020-02-24 6:51 [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings pannengyuan
2020-03-03 10:14 ` Laurent Vivier
@ 2020-03-03 10:47 ` Paolo Bonzini
2020-03-03 10:58 ` Pan Nengyuan
1 sibling, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2020-03-03 10:47 UTC (permalink / raw)
To: pannengyuan, rth, ehabkost
Cc: qemu-trivial, euler.robot, qemu-devel, zhang.zhanghailiang
On 24/02/20 07:51, pannengyuan@huawei.com wrote:
> diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c
> index a5426a6dac..197d5bc0f9 100644
> --- a/target/i386/hax-posix.c
> +++ b/target/i386/hax-posix.c
> @@ -121,7 +121,8 @@ static char *hax_vm_devfs_string(int vm_id)
> return NULL;
> }
>
> - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> + int len = snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
> + assert(len < sizeof HAX_VM_DEVFS);
> return name;
> }
>
> @@ -140,8 +141,9 @@ static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
> return NULL;
> }
>
> - snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> - vm_id, vcpu_id);
> + int len = snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
> + vm_id, vcpu_id);
> + assert(len < sizeof HAX_VCPU_DEVFS);
> return name;
> }
>
>
Julio Faracco has posted a fix for the same bug. The best change is
actually to switch to g_strdup_printf.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings
2020-03-03 10:47 ` Paolo Bonzini
@ 2020-03-03 10:58 ` Pan Nengyuan
0 siblings, 0 replies; 4+ messages in thread
From: Pan Nengyuan @ 2020-03-03 10:58 UTC (permalink / raw)
To: Paolo Bonzini, rth, ehabkost
Cc: qemu-trivial, euler.robot, qemu-devel, zhang.zhanghailiang
On 3/3/2020 6:47 PM, Paolo Bonzini wrote:
> On 24/02/20 07:51, pannengyuan@huawei.com wrote:
>> diff --git a/target/i386/hax-posix.c b/target/i386/hax-posix.c
>> index a5426a6dac..197d5bc0f9 100644
>> --- a/target/i386/hax-posix.c
>> +++ b/target/i386/hax-posix.c
>> @@ -121,7 +121,8 @@ static char *hax_vm_devfs_string(int vm_id)
>> return NULL;
>> }
>>
>> - snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
>> + int len = snprintf(name, sizeof HAX_VM_DEVFS, "/dev/hax_vm/vm%02d", vm_id);
>> + assert(len < sizeof HAX_VM_DEVFS);
>> return name;
>> }
>>
>> @@ -140,8 +141,9 @@ static char *hax_vcpu_devfs_string(int vm_id, int vcpu_id)
>> return NULL;
>> }
>>
>> - snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
>> - vm_id, vcpu_id);
>> + int len = snprintf(name, sizeof HAX_VCPU_DEVFS, "/dev/hax_vm%02d/vcpu%02d",
>> + vm_id, vcpu_id);
>> + assert(len < sizeof HAX_VCPU_DEVFS);
>> return name;
>> }
>>
>>
>
> Julio Faracco has posted a fix for the same bug. The best change is
> actually to switch to g_strdup_printf.
Okay, Thanks.
>
> Paolo
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-02-24 6:51 [PATCH] target/i386/hax-posix: fix two 'format-truncation' compile warnings pannengyuan
2020-03-03 10:14 ` Laurent Vivier
2020-03-03 10:47 ` Paolo Bonzini
2020-03-03 10:58 ` Pan Nengyuan
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