On 2026-07-13 14:00, Ricardo Robaina wrote: > Modern mount tools (util-linux >= 2.39.1) use the new mount API > (fsopen, fsconfig, fsmount, move_mount) instead of the legacy mount(2) > syscall. The generic SYSCALL audit record logs the move_mount syscall > but does not capture the flags argument, creating an audit gap for > mount relocation operations. > > Add a MOVE_MOUNT auxiliary record that logs the flags argument passed > to move_mount(2). Pathnames and file descriptors are captured through > existing PATH records and SYSCALL record arguments. > > ---- > type=PATH : item=0 name=/mnt/test_src inode=1 dev=00:41 ... > type=SYSCALL : arch=x86_64 syscall=move_mount ... > type=MOVE_MOUNT : fs_flags=0x4 > ---- > type=PATH : item=0 name=/mnt/test_dst inode=27460862 dev=fc:00 ... > type=SYSCALL : arch=x86_64 syscall=move_mount ... > type=MOVE_MOUNT : fs_flags=0x4 > > Link: https://github.com/linux-audit/audit-kernel/issues/152 > Link: https://github.com/linux-audit/audit-kernel/issues/153 > Signed-off-by: Ricardo Robaina <[email protected]>
Reviewed-by: Richard Guy Briggs <[email protected]> > --- > fs/namespace.c | 3 +++ > include/linux/audit.h | 10 ++++++++++ > include/uapi/linux/audit.h | 1 + > kernel/auditsc.c | 13 +++++++++++++ > 4 files changed, 27 insertions(+) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 3d5cd5bf3b05..a6b0286744d9 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -34,6 +34,7 @@ > #include <linux/mnt_idmapping.h> > #include <linux/pidfs.h> > #include <linux/nstree.h> > +#include <linux/audit.h> > > #include "pnode.h" > #include "internal.h" > @@ -4625,6 +4626,8 @@ SYSCALL_DEFINE5(move_mount, > if (flags & MOVE_MOUNT_F_EMPTY_PATH) > uflags = AT_EMPTY_PATH; > > + audit_log_move_mount(flags); > + > CLASS(filename_maybe_null,from_name)(from_pathname, uflags); > if (!from_name && from_dfd >= 0) { > CLASS(fd_raw, f_from)(from_dfd); > diff --git a/include/linux/audit.h b/include/linux/audit.h > index 45abb3722d30..d1dc4035cb3c 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -449,6 +449,7 @@ 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, > enum audit_nfcfgop op, gfp_t gfp); > +extern void __audit_log_move_mount(unsigned int flags); > > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) > { > @@ -598,6 +599,12 @@ static inline void audit_log_nfcfg(const char *name, u8 > af, > __audit_log_nfcfg(name, af, nentries, op, gfp); > } > > +static inline void audit_log_move_mount(unsigned int flags) > +{ > + if (!audit_dummy_context()) > + __audit_log_move_mount(flags); > +} > + > extern int audit_n_rules; > extern int audit_signals; > #else /* CONFIG_AUDITSYSCALL */ > @@ -730,6 +737,9 @@ static inline void audit_log_nfcfg(const char *name, u8 > af, > enum audit_nfcfgop op, gfp_t gfp) > { } > > +static inline void audit_log_move_mount(unsigned int flags) > +{ } > + > #define audit_n_rules 0 > #define audit_signals 0 > #endif /* CONFIG_AUDITSYSCALL */ > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > index e8f5ce677df7..40abf3dfd307 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -122,6 +122,7 @@ > #define AUDIT_OPENAT2 1337 /* Record showing openat2 how > args */ > #define AUDIT_DM_CTRL 1338 /* Device Mapper target control > */ > #define AUDIT_DM_EVENT 1339 /* Device Mapper events */ > +#define AUDIT_MOVE_MOUNT 1342 /* Record showing move_mount flags */ > > #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ > #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 6610e667c728..4aca04d33d00 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -2882,6 +2882,19 @@ void __audit_log_nfcfg(const char *name, u8 af, > unsigned int nentries, > } > EXPORT_SYMBOL_GPL(__audit_log_nfcfg); > > +void __audit_log_move_mount(unsigned int flags) > +{ > + struct audit_buffer *ab; > + > + ab = audit_log_start(audit_context(), GFP_KERNEL, > + AUDIT_MOVE_MOUNT); > + if (!ab) > + return; > + > + audit_log_format(ab, "fs_flags=0x%x", flags); > + audit_log_end(ab); > +} > + > static void audit_log_task(struct audit_buffer *ab) > { > kuid_t auid, uid; > -- > 2.53.0 - RGB -- Richard Guy Briggs <[email protected]> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada Upstream IRC: SunRaycer Voice: +1.613.860 2354 SMS: +1.613.518.6570
