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    SubjectRe: [AppArmor 37/41] AppArmor: Main Part
    > + * aa_taskattr_access
    > + * @name: name of the file to check
    > + *
    > + * Check if name matches /proc/self/attr/current, with self resolved
    > + * to the current pid. This file is the usermode iterface for
    > + * changing one's hat.
    > + */
    > +static inline int aa_taskattr_access(const char *name)
    > +{
    > + unsigned long pid;
    > + char *end;
    > +
    > + if (strncmp(name, "/proc/", 6) != 0)
    > + return 0;

    The proc file system may not be mounted at /proc. There are environments
    where this is done for good reason (eg not wanting the /proc info exposed
    to a low trust environment). Another is when FUSE is providing an
    arbitrated proc either by merging across clusters or by removing stuff.

    > +static int aa_file_denied(struct aa_profile *profile, const char *name,
    > + int mask)
    > +{
    > + int perms;
    > +
    > + /* Always allow write access to /proc/self/attr/current. */
    > + if (mask == MAY_WRITE && aa_taskattr_access(name))
    > + return 0;

    Why can't this be done in the profile itself to avoid kernel special case
    uglies and inflexibility ?

    > + if (PTR_ERR(sa->name) == -ENOENT && (check & AA_CHECK_FD))
    > + denied_mask = 0;

    Now there is an interesting question. Is PTR_ERR() safe for kernel
    pointers on all platforms or just for user ones ?


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