Hello,
Sorry to take so long. Holidays and kernel build problems. However, I have
built a kernel with these patches. I only have 2 comments. When I use an
application that expected the old API, meaning it simply does:
response.fd = metadata->fd;
response.response = reply;
close(metadata->fd);
write(fd, &response, sizeof(struct fanotify_response));
I get access denials. Every time. If the program is using the new API and
sets FAN_INFO, then it works as expected. I'll do some more testing but I
think there is something wrong in the compatibility path.
On Monday, December 12, 2022 9:06:11 AM EST Richard Guy Briggs wrote:
> This patch passes the full response so that the audit function can use all
> of it. The audit function was updated to log the additional information in
> the AUDIT_FANOTIFY record.
What I'm seeing is:
type=FANOTIFY msg=audit(01/09/2023 18:43:16.306:366) : resp=deny fan_type=1
fan_info=313300000000000000000000 subj_trust=0 obj_trust=0
Where fan_info was supposed to be 13 decimal. More below...
> Currently the only type of fanotify info that is defined is an audit
> rule number, but convert it to hex encoding to future-proof the field.
> Hex encoding suggested by Paul Moore <paul@xxxxxxxxxxxxxx>.
>
> Sample records:
> type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1
> fan_info=3137 subj_trust=3 obj_trust=5 type=FANOTIFY
> msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=3F subj_trust=2
> obj_trust=2
>
> Suggested-by: Steve Grubb <sgrubb@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify.c | 3 ++-
> include/linux/audit.h | 9 +++++----
> kernel/auditsc.c | 25 ++++++++++++++++++++++---
> 3 files changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 24ec1d66d5a8..29bdd99b29fa 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -273,7 +273,8 @@ static int fanotify_get_response(struct fsnotify_group
> *group,
>
> /* Check if the response should be audited */
> if (event->response & FAN_AUDIT)
> - audit_fanotify(event->response & ~FAN_AUDIT);
> + audit_fanotify(event->response & ~FAN_AUDIT,
> + &event->audit_rule);
>
> pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__,
> group, event, ret);
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index d6b7d0c7ce43..31086a72e32a 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -14,6 +14,7 @@
> #include <linux/audit_arch.h>
> #include <uapi/linux/audit.h>
> #include <uapi/linux/netfilter/nf_tables.h>
> +#include <uapi/linux/fanotify.h>
>
> #define AUDIT_INO_UNSET ((unsigned long)-1)
> #define AUDIT_DEV_UNSET ((dev_t)-1)
> @@ -416,7 +417,7 @@ extern void __audit_log_capset(const struct cred *new,
> const struct cred *old); extern void __audit_mmap_fd(int fd, int flags);
> extern void __audit_openat2_how(struct open_how *how);
> extern void __audit_log_kern_module(char *name);
> -extern void __audit_fanotify(u32 response);
> +extern void __audit_fanotify(u32 response, struct
> fanotify_response_info_audit_rule *friar); extern void
> __audit_tk_injoffset(struct timespec64 offset);
> extern void __audit_ntp_log(const struct audit_ntp_data *ad);
> extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int
> nentries, @@ -523,10 +524,10 @@ static inline void
> audit_log_kern_module(char *name) __audit_log_kern_module(name);
> }
>
> -static inline void audit_fanotify(u32 response)
> +static inline void audit_fanotify(u32 response, struct
> fanotify_response_info_audit_rule *friar) {
> if (!audit_dummy_context())
> - __audit_fanotify(response);
> + __audit_fanotify(response, friar);
> }
>
> static inline void audit_tk_injoffset(struct timespec64 offset)
> @@ -679,7 +680,7 @@ static inline void audit_log_kern_module(char *name)
> {
> }
>
> -static inline void audit_fanotify(u32 response)
> +static inline void audit_fanotify(u32 response, struct
> fanotify_response_info_audit_rule *friar) { }
>
> static inline void audit_tk_injoffset(struct timespec64 offset)
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d1fb821de104..8d523066d81f 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -64,6 +64,7 @@
> #include <uapi/linux/limits.h>
> #include <uapi/linux/netfilter/nf_tables.h>
> #include <uapi/linux/openat2.h> // struct open_how
> +#include <uapi/linux/fanotify.h>
>
> #include "audit.h"
>
> @@ -2877,10 +2878,28 @@ void __audit_log_kern_module(char *name)
> context->type = AUDIT_KERN_MODULE;
> }
>
> -void __audit_fanotify(u32 response)
> +void __audit_fanotify(u32 response, struct
> fanotify_response_info_audit_rule *friar) {
> - audit_log(audit_context(), GFP_KERNEL,
> - AUDIT_FANOTIFY, "resp=%u", response);
> + struct audit_context *ctx = audit_context();
> + struct audit_buffer *ab;
> + char numbuf[12];
> +
> + if (friar->hdr.type == FAN_RESPONSE_INFO_NONE) {
> + audit_log(audit_context(), GFP_KERNEL, AUDIT_FANOTIFY,
> + "resp=%u fan_type=%u fan_info=3F subj_trust=2
obj_trust=2",
> + response, FAN_RESPONSE_INFO_NONE);
> + return;
> + }
> + ab = audit_log_start(ctx, GFP_KERNEL, AUDIT_FANOTIFY);
> + if (ab) {
> + audit_log_format(ab, "resp=%u fan_type=%u fan_info=",
> + response, friar->hdr.type);
> + snprintf(numbuf, sizeof(numbuf), "%u", friar->rule_number);
> + audit_log_n_hex(ab, numbuf, sizeof(numbuf));
I don't think it needs to be converted to ascii and then hexencoded. As Paul
said, probably %X is all we need here.
-Steve
> + audit_log_format(ab, " subj_trust=%u obj_trust=%u",
> + friar->subj_trust, friar->obj_trust);
> + audit_log_end(ab);
> + }
> }
>
> void __audit_tk_injoffset(struct timespec64 offset)
