[PATCH] audit: restore AUDIT_LOGINUID unset ABI
Richard Guy Briggs
rgb at redhat.com
Wed Sep 24 14:20:07 UTC 2014
On 14/09/24, Richard Guy Briggs wrote:
> A regression was caused by commit 780a7654cee8:
> audit: Make testing for a valid loginuid explicit.
> (which in turn attempted to fix a regression caused by e1760bd)
Eric (Paris), does tagging this field in the type member with a high
bit work for you? It only has to be filtered out for
audit_filter_user_rules() and audit_filter_rules() to avoid changing the
normal semantics of that field. I'd rather do this than add a new
member to the field struct.
> When audit_krule_to_data() fills in the rules to get a listing, there was a
> missing clause to convert back from AUDIT_LOGINUID_SET to AUDIT_LOGINUID.
>
> This broke userspace by not returning the same information that was sent and
> expected.
>
> The rule:
> auditctl -a exit,never -F auid=-1
> gives:
> auditctl -l
> LIST_RULES: exit,never f24=0 syscall=all
> when it should give:
> LIST_RULES: exit,never auid=-1 (0xffffffff) syscall=all
>
> Tag it so that it is reported the same way it was set.
>
> Note: move the field validation call ahead of the mutation code to have it work
> on the original field set.
>
I intend to add a Cc: stable 3.10-rc1 here.
> Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
> ---
> include/uapi/linux/audit.h | 3 +++
> kernel/auditfilter.c | 19 +++++++++++++------
> kernel/auditsc.c | 2 +-
> 3 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index 4d100c8..860df86 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -274,6 +274,9 @@
>
> #define AUDIT_FILTERKEY 210
>
> +/* Flag to indicate legacy AUDIT_LOGINUID unset usage */
> +#define AUDIT_LOGINUID_LEGACY 0x80000000
> +
> #define AUDIT_NEGATE 0x80000000
>
> /* These are the supported operators.
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index 40ed981..39ce3e6 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -438,9 +438,13 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
> f->type = data->fields[i];
> f->val = data->values[i];
>
> + err = audit_field_valid(entry, f);
> + if (err)
> + goto exit_free;
> +
> /* Support legacy tests for a valid loginuid */
> if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) {
> - f->type = AUDIT_LOGINUID_SET;
> + f->type = AUDIT_LOGINUID_SET | AUDIT_LOGINUID_LEGACY;
> f->val = 0;
> }
>
> @@ -457,10 +461,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
> rcu_read_unlock();
> }
>
> - err = audit_field_valid(entry, f);
> - if (err)
> - goto exit_free;
> -
> err = -EINVAL;
> switch (f->type) {
> case AUDIT_LOGINUID:
> @@ -630,6 +630,13 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
> data->buflen += data->values[i] =
> audit_pack_string(&bufp, krule->filterkey);
> break;
> + case AUDIT_LOGINUID_SET | AUDIT_LOGINUID_LEGACY:
> + if (!f->val) {
> + data->fields[i] = AUDIT_LOGINUID;
> + data->values[i] = AUDIT_UID_UNSET;
> + break;
> + }
> + /* fallthrough if set */
> default:
> data->values[i] = f->val;
> }
> @@ -1270,7 +1277,7 @@ static int audit_filter_user_rules(struct audit_krule *rule, int type,
> int result = 0;
> u32 sid;
>
> - switch (f->type) {
> + switch (f->type & ~AUDIT_LOGINUID_LEGACY) {
> case AUDIT_PID:
> pid = task_pid_nr(current);
> result = audit_comparator(pid, f->op, f->val);
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 8933572..ef25cbc 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -452,7 +452,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> int result = 0;
> pid_t pid;
>
> - switch (f->type) {
> + switch (f->type & ~AUDIT_LOGINUID_LEGACY) {
> case AUDIT_PID:
> pid = task_pid_nr(tsk);
> result = audit_comparator(pid, f->op, f->val);
> --
> 1.7.1
>
- RGB
--
Richard Guy Briggs <rbriggs at redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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