On Tue, 2014-01-28 at 13:17 +0100, Geert Uytterhoeven wrote:
> On Tue, Jan 28, 2014 at 1:04 PM, Ingo Molnar <mi...@kernel.org> wrote:
> > * Geert Uytterhoeven <ge...@linux-m68k.org> wrote:
> >> On Sun, Jan 26, 2014 at 9:25 PM, Ingo Molnar <mi...@kernel.org> wrote:
> >> > * Ingo Molnar <mi...@kernel.org> wrote:
> >> >> * Linus Torvalds <torva...@linux-foundation.org> wrote:
> >> >> > On Sun, Jan 26, 2014 at 4:27 AM, David Howells <dhowe...@redhat.com>
> >> >> > wrote:
> >> >> > > - p = proc_create("cells", 0, proc_afs, &afs_proc_cells_fops);
> >> >> > > + p = proc_create("cells", S_IFREG | S_IRUGO | S_IWUSR,
> >> >> > > proc_afs, &afs_proc_cells_fops);
> >> >> > > - p = proc_create("rootcell", 0, proc_afs,
> >> >> > > &afs_proc_rootcell_fops);
> >> >> > > + p = proc_create("rootcell", S_IFREG | S_IRUGO | S_IWUSR,
> >> >> > > proc_afs, &afs_proc_rootcell_fops);
> >> >> >
> >> >> > So the S_IFREG isn't necessary.
> >> >> >
> >> >> > And quite frankly, I personally think S_IRUGO | S_IWUSR is _less_
> >> >> > readable than 0644. It's damn hard to parse those random letter
> >> >> > combinations, and at least I have to really think about it, in a way
> >> >> > that the octal representation does *not* make me go "I have to think
> >> >> > about that".
> >> >> >
> >> >> > So my personal preference would be to just see that simple 0644 in
> >> >> > proc_create. Hmm?
I don't have an issue with octal uses here either.
I think just as clear if not clearer than defines like
#define {whatever_}rwxrwxrwx 0777
#define {whatever_}rw_r__r__ 0644
#define {whatever_}r________ 0400
etc...
> >> Only a limited number of combinations is in active use, right?
> > Correct - and in fact that kind of limitation is also a security
> > feature: using patterns _outside_ of the typical, already defined
> > group of permission patterns would in itself be a 'is that really
> > justified?' red flag during review.
>
> Then Joe (CCed :-) can write a checkpatch rule to flag all new users of the
> I_S[RWX}* flags..,
Flagging all "odd" uses of octal too?
Perhaps a checkpatch rule might look something like:
---
scripts/checkpatch.pl | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0ea2a1e..bf278e0 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -328,6 +328,12 @@ our $typeTypedefs = qr{(?x:
atomic_t
)};
+our $permissions = qr{(?x:
+ S_I[RWX](?:USR|GRP|OTH)|
+ S_IRWX[UGO]|
+ S_I(?:RWX|ALL|R|W|X)UGO
+)};
+
our $logFunctions = qr{(?x:
printk(?:_ratelimited|_once|)|
(?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
@@ -4457,6 +4463,15 @@ sub process {
WARN("EXPORTED_WORLD_WRITABLE",
"Exporting world writable files is usually an
error. Consider more restrictive permissions.\n" . $herecurr);
}
+
+# check for uses of permissions S_I<FOO> defines
+ if ($line =~ /\b($permissions)\b/) {
+ my $perm = $1;
+ my $msg_type = \&WARN;
+ $msg_type = \&CHK if ($file);
+ &{$msg_type}("PERMISSIONS",
+ "Use of $perm is not preferred.\n" .
$herecurr);
+ }
}
# If we have no input at all, then there is nothing to report on
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