On Wed, Jul 30, 2008 at 03:02:03PM +0200, Miklos Szeredi wrote:
> static int coda_ioctl_permission(struct inode *inode, int mask)
> {
> - return 0;
> + return check_execute(dentry->d_inode, mask);
> }
Er?
a) mismerge from dentry-based variant
b) I'd say return mask & MAY_EXEC ? -EACCES : 0 - it's *NOT* going to
be an executable file, TYVM.
> static int hfs_permission(struct inode *inode, int mask)
> {
> if (S_ISREG(inode->i_mode) && mask & MAY_EXEC)
> - return 0;
> + return check_execute(inode, mask);
> return generic_permission(inode, mask, NULL);
> }
WTF is going on in that one? I realize that you are not changing behaviour,
but...
> +int check_execute(struct inode *inode, int mask)
> +{
> + if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
> + !(inode->i_mode & S_IXUGO))
> + return -EACCES;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(check_execute);
Umm... I'm not sure. For one thing, I'd take check for MAY_EXEC to callers.
For another, quite a few of those might have enough information to make calling
that helper pointless.
> +++ linux-2.6/fs/proc/proc_sysctl.c 2008-07-30 14:39:31.000000000 +0200
> @@ -311,6 +311,9 @@ static int proc_sys_permission(struct in
> error = sysctl_perm(head->root, table, mask);
>
> sysctl_head_finish(head);
> + if (!error)
> + error = check_execute(inode, mask);
> +
> return error;
> }
No. If anything, we want non-directories fail MAY_EXEC here, no matter
what i_mode we might have. Executable files in /proc/sys/* are NOT going
to be allowed, no matter what...
> if (mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC))
> - error = -EACCES;
> - return error;
> + return -EACCES;
> +
> + return check_execute(inode, mask);
That's wrong. If mask contains MAY_EXEC and we got to calling check_execute(),
we know that ~mode & MAY_EXEC is 0. IOW, we know that inode->i_mode >> 6 has
bit 0 set. IOW, we know that inode->i_mode contain S_IXUSR. IOW, your
check_execute() here is an obfuscated way to spell 0.
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