Since the openat2(2) syscall uses a struct open_how pointer to communicate its parameters they are not usefully recorded by the audit SYSCALL record's four existing arguments. Add a new audit record type OPENAT2 that reports the parameters in its third argument, struct open_how with fields oflag, mode and resolve. The new record in the context of an event would look like: time->Wed Mar 17 16:28:53 2021 type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432 type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0 type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0 type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests" type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO" Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@xxxxxxxxxx --- fs/open.c | 2 ++ include/linux/audit.h | 10 ++++++++++ include/uapi/linux/audit.h | 1 + kernel/audit.h | 2 ++ kernel/auditsc.c | 18 +++++++++++++++++- 5 files changed, 32 insertions(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index e53af13b5835..2a15bec0cf6d 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1235,6 +1235,8 @@ SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename, if (err) return err; + audit_openat2_how(&tmp); + /* O_LARGEFILE is only allowed for non-O_PATH. */ if (!(tmp.flags & O_PATH) && force_o_largefile()) tmp.flags |= O_LARGEFILE; diff --git a/include/linux/audit.h b/include/linux/audit.h index 283bc91a6932..580a52caf16f 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -399,6 +399,7 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm, const struct cred *old); 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(unsigned int response); extern void __audit_tk_injoffset(struct timespec64 offset); @@ -495,6 +496,12 @@ static inline void audit_mmap_fd(int fd, int flags) __audit_mmap_fd(fd, flags); } +static inline void audit_openat2_how(struct open_how *how) +{ + if (unlikely(!audit_dummy_context())) + __audit_openat2_how(how); +} + static inline void audit_log_kern_module(char *name) { if (!audit_dummy_context()) @@ -646,6 +653,9 @@ static inline void audit_log_capset(const struct cred *new, static inline void audit_mmap_fd(int fd, int flags) { } +static inline void audit_openat2_how(struct open_how *how) +{ } + static inline void audit_log_kern_module(char *name) { } diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index cd2d8279a5e4..67aea2370c6d 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -118,6 +118,7 @@ #define AUDIT_TIME_ADJNTPVAL 1333 /* NTP value adjustment */ #define AUDIT_BPF 1334 /* BPF subsystem */ #define AUDIT_EVENT_LISTENER 1335 /* Task joined multicast read socket */ +#define AUDIT_OPENAT2 1336 /* Record showing openat2 how args */ #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ diff --git a/kernel/audit.h b/kernel/audit.h index 1522e100fd17..c5af17905976 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -11,6 +11,7 @@ #include <linux/skbuff.h> #include <uapi/linux/mqueue.h> #include <linux/tty.h> +#include <uapi/linux/openat2.h> // struct open_how /* AUDIT_NAMES is the number of slots we reserve in the audit_context * for saving names from getname(). If we get more names we will allocate @@ -185,6 +186,7 @@ struct audit_context { int fd; int flags; } mmap; + struct open_how openat2; struct { int argc; } execve; diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3f59ab209dfd..faf2485323a9 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -76,7 +76,7 @@ #include <linux/fsnotify_backend.h> #include <uapi/linux/limits.h> #include <uapi/linux/netfilter/nf_tables.h> -#include <uapi/linux/openat2.h> +#include <uapi/linux/openat2.h> // struct open_how #include "audit.h" @@ -1319,6 +1319,12 @@ static void show_special(struct audit_context *context, int *call_panic) audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd, context->mmap.flags); break; + case AUDIT_OPENAT2: + audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx", + context->openat2.flags, + context->openat2.mode, + context->openat2.resolve); + break; case AUDIT_EXECVE: audit_log_execve_info(context, &ab); break; @@ -2549,6 +2555,16 @@ void __audit_mmap_fd(int fd, int flags) context->type = AUDIT_MMAP; } +void __audit_openat2_how(struct open_how *how) +{ + struct audit_context *context = audit_context(); + + context->openat2.flags = how->flags; + context->openat2.mode = how->mode; + context->openat2.resolve = how->resolve; + context->type = AUDIT_OPENAT2; +} + void __audit_log_kern_module(char *name) { struct audit_context *context = audit_context(); -- 2.27.0
