Re: [PATCH v4 2/3] audit: add support for the openat2 syscall

Hi Richard - On 5/19/21 16:00, Richard Guy Briggs wrote: > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9 > ("open: introduce openat2(2) syscall") > > Add the openat2(2) syscall to the audit syscall classifier. > > Link: https://github.com/linux-audit/audit-kernel/issues/67 > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.162136... > --- [...] > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index d775ea16505b..3f59ab209dfd 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -76,6 +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 "audit.h" > > @@ -196,6 +197,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask) > return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND); > case AUDITSC_EXECVE: > return mask & AUDIT_PERM_EXEC; > + case AUDITSC_OPENAT2: > + return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags); > default: > return 0; > } ctx->argv[2] holds a userspace pointer and can't be dereferenced like this. I'm getting oopses, like so: BUG: unable to handle page fault for address: 00007fff961bbe70