* [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements
@ 2020-09-15 16:03 Colin King
2020-09-16 6:14 ` Hans de Goede
0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2020-09-15 16:03 UTC (permalink / raw)
To: Hans de Goede, Christoph Hellwig, Al Viro, linux-fsdevel
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The comparison of signed char constants with unsigned char array
elements leads to checks that are always false. Fix this by declaring
the VBSF_MOUNT_SIGNATURE_BYTE* macros as octal unsigned int constants
rather than as signed char constants. (Argueably the U is not necessarily
required, but add it to be really clear of intent).
Addresses-Coverity: ("Operands don't affect result")
Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
fs/vboxsf/super.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index 25aade344192..986efcb29cc2 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -21,10 +21,10 @@
#define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
-#define VBSF_MOUNT_SIGNATURE_BYTE_0 ('\000')
-#define VBSF_MOUNT_SIGNATURE_BYTE_1 ('\377')
-#define VBSF_MOUNT_SIGNATURE_BYTE_2 ('\376')
-#define VBSF_MOUNT_SIGNATURE_BYTE_3 ('\375')
+#define VBSF_MOUNT_SIGNATURE_BYTE_0 0000U
+#define VBSF_MOUNT_SIGNATURE_BYTE_1 0377U
+#define VBSF_MOUNT_SIGNATURE_BYTE_2 0376U
+#define VBSF_MOUNT_SIGNATURE_BYTE_3 0375U
static int follow_symlinks;
module_param(follow_symlinks, int, 0444);
--
2.27.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements
2020-09-15 16:03 [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements Colin King
@ 2020-09-16 6:14 ` Hans de Goede
2020-09-16 7:20 ` Sedat Dilek
0 siblings, 1 reply; 3+ messages in thread
From: Hans de Goede @ 2020-09-16 6:14 UTC (permalink / raw)
To: Colin King, Christoph Hellwig, Al Viro, linux-fsdevel
Cc: kernel-janitors, linux-kernel
Hi,
On 9/15/20 6:03 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The comparison of signed char constants with unsigned char array
> elements leads to checks that are always false. Fix this by declaring
> the VBSF_MOUNT_SIGNATURE_BYTE* macros as octal unsigned int constants
> rather than as signed char constants. (Argueably the U is not necessarily
> required, but add it to be really clear of intent).
>
> Addresses-Coverity: ("Operands don't affect result")
> Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
A fix for this has already been queued up:
https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/log/?h=fixes
Explicit nack for this one, since it will still apply, but combined
with the other fix, it will re-break things.
Regards,
Hans
> ---
> fs/vboxsf/super.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
> index 25aade344192..986efcb29cc2 100644
> --- a/fs/vboxsf/super.c
> +++ b/fs/vboxsf/super.c
> @@ -21,10 +21,10 @@
>
> #define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
>
> -#define VBSF_MOUNT_SIGNATURE_BYTE_0 ('\000')
> -#define VBSF_MOUNT_SIGNATURE_BYTE_1 ('\377')
> -#define VBSF_MOUNT_SIGNATURE_BYTE_2 ('\376')
> -#define VBSF_MOUNT_SIGNATURE_BYTE_3 ('\375')
> +#define VBSF_MOUNT_SIGNATURE_BYTE_0 0000U
> +#define VBSF_MOUNT_SIGNATURE_BYTE_1 0377U
> +#define VBSF_MOUNT_SIGNATURE_BYTE_2 0376U
> +#define VBSF_MOUNT_SIGNATURE_BYTE_3 0375U
>
> static int follow_symlinks;
> module_param(follow_symlinks, int, 0444);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements
2020-09-16 6:14 ` Hans de Goede
@ 2020-09-16 7:20 ` Sedat Dilek
0 siblings, 0 replies; 3+ messages in thread
From: Sedat Dilek @ 2020-09-16 7:20 UTC (permalink / raw)
To: Hans de Goede
Cc: Colin King, Christoph Hellwig, Al Viro, linux-fsdevel,
kernel-janitors, linux-kernel
On Wed, Sep 16, 2020 at 8:16 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi,
>
> On 9/15/20 6:03 PM, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > The comparison of signed char constants with unsigned char array
> > elements leads to checks that are always false. Fix this by declaring
> > the VBSF_MOUNT_SIGNATURE_BYTE* macros as octal unsigned int constants
> > rather than as signed char constants. (Argueably the U is not necessarily
> > required, but add it to be really clear of intent).
> >
> > Addresses-Coverity: ("Operands don't affect result")
> > Fixes: 0fd169576648 ("fs: Add VirtualBox guest shared folder (vboxsf) support")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
>
> A fix for this has already been queued up:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/log/?h=fixes
>
> Explicit nack for this one, since it will still apply, but combined
> with the other fix, it will re-break things.
>
Hans, your patch is from 2020-08-25 and in a "fixes" Git branch of vfs
- why wasn't it applied to Linux 5.9?
- Sedat -
> Regards,
>
> Hans
>
>
>
> > ---
> > fs/vboxsf/super.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
> > index 25aade344192..986efcb29cc2 100644
> > --- a/fs/vboxsf/super.c
> > +++ b/fs/vboxsf/super.c
> > @@ -21,10 +21,10 @@
> >
> > #define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
> >
> > -#define VBSF_MOUNT_SIGNATURE_BYTE_0 ('\000')
> > -#define VBSF_MOUNT_SIGNATURE_BYTE_1 ('\377')
> > -#define VBSF_MOUNT_SIGNATURE_BYTE_2 ('\376')
> > -#define VBSF_MOUNT_SIGNATURE_BYTE_3 ('\375')
> > +#define VBSF_MOUNT_SIGNATURE_BYTE_0 0000U
> > +#define VBSF_MOUNT_SIGNATURE_BYTE_1 0377U
> > +#define VBSF_MOUNT_SIGNATURE_BYTE_2 0376U
> > +#define VBSF_MOUNT_SIGNATURE_BYTE_3 0375U
> >
> > static int follow_symlinks;
> > module_param(follow_symlinks, int, 0444);
> >
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-09-15 16:03 [PATCH] vboxsf: fix comparison of signed char constant with unsigned char array elements Colin King
2020-09-16 6:14 ` Hans de Goede
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