The fanotify interface allows user space daemons to make access control decisions. Under common criteria requirements, we need to optionally record decisions based on policy. This patch adds a bit mask, FAN_AUDIT, that a user space daemon can 'or' into the response decision which will tell the kernel that it made a decision and record it. It would be used something like this in user space code: response.response = FAN_DENY | FAN_AUDIT; write(fd, &response, sizeof(struct fanotify_response)); When the syscall ends, the audit system will record the decision as a AUDIT_FANOTIFY auxiliary record to denote that the reason this event occurred is the result of an access control decision from fanotify rather than DAC or MAC policy. A sample event looks like this: type=PATH msg=audit(1504310584.332:290): item=0 name="./evil-ls" inode=1319561 dev=fc:03 mode=0100755 ouid=1000 ogid=1000 rdev=00:00 obj=unconfined_u:object_r:user_home_t:s0 nametype=NORMAL type=CWD msg=audit(1504310584.332:290): cwd="/home/sgrubb" type=SYSCALL msg=audit(1504310584.332:290): arch=c000003e syscall=2 success=no exit=-1 a0=32cb3fca90 a1=0 a2=43 a3=8 items=1 ppid=901 pid=959 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="bash" exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t: s0-s0:c0.c1023 key=(null) type=FANOTIFY msg=audit(1504310584.332:290): resp=2 Prior to using the audit flag, the developer needs to call fanotify_init or'ing in FAN_ENABLE_AUDIT to ensure that the kernel supports auditing. The calling process must also have the CAP_AUDIT_WRITE capability.
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| @@ -112,6 +112,7 @@ · 111 unmodified lines | |||
| 112 | #define AUDIT_FEATURE_CHANGE 1328 /* audit log listing feature changes */ | 112 | #define AUDIT_FEATURE_CHANGE 1328 /* audit log listing feature changes */ |
| 113 | #define AUDIT_REPLACE 1329 /* Replace auditd if this packet unanswerd */ | 113 | #define AUDIT_REPLACE 1329 /* Replace auditd if this packet unanswerd */ |
| 114 | #define AUDIT_KERN_MODULE 1330 /* Kernel Module events */ | 114 | #define AUDIT_KERN_MODULE 1330 /* Kernel Module events */ |
| 115 | #define AUDIT_FANOTIFY 1331 /* Fanotify access decision */ | ||
| 115 | 116 | ||
| 116 | #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ | 117 | #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ |
| 117 | #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ | 118 | #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ |
| @@ -35,6 +35,7 @@ · 34 unmodified lines | |||
| 35 | 35 | ||
| 36 | #define FAN_UNLIMITED_QUEUE 0x00000010 | 36 | #define FAN_UNLIMITED_QUEUE 0x00000010 |
| 37 | #define FAN_UNLIMITED_MARKS 0x00000020 | 37 | #define FAN_UNLIMITED_MARKS 0x00000020 |
| 38 | #define FAN_ENABLE_AUDIT 0x00000040 | ||
| 38 | 39 | ||
| 39 | #define FAN_ALL_INIT_FLAGS (FAN_CLOEXEC | FAN_NONBLOCK | \ | 40 | #define FAN_ALL_INIT_FLAGS (FAN_CLOEXEC | FAN_NONBLOCK | \ |
| 40 | FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\ | 41 | FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\ |
| @@ -99,6 +100,8 @@ struct fanotify_response { · 58 unmodified lines | |||
| 99 | /* Legit userspace responses to a _PERM event */ | 100 | /* Legit userspace responses to a _PERM event */ |
| 100 | #define FAN_ALLOW 0x01 | 101 | #define FAN_ALLOW 0x01 |
| 101 | #define FAN_DENY 0x02 | 102 | #define FAN_DENY 0x02 |
| 103 | #define FAN_AUDIT 0x10 /* Bit mask to create audit record for result */ | ||
| 104 | |||
| 102 | /* No fd set in event */ | 105 | /* No fd set in event */ |
| 103 | #define FAN_NOFD -1 | 106 | #define FAN_NOFD -1 |
| 104 | 107 | ||