audit: call audit_bprm() only once to add AUDIT_EXECVE information

Move the audit_bprm() call from search_binary_handler() to exec_binprm().  This
allows us to get rid of the mm member of struct audit_aux_data_execve since
bprm->mm will equal current->mm.

This also mitigates the issue that ->argc could be modified by the
load_binary() call in search_binary_handler().

audit_bprm() was being called to add an AUDIT_EXECVE record to the audit
context every time search_binary_handler() was recursively called.  Only one
reference is necessary.

Reported-by: Oleg Nesterov <onestero@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
---
This patch is against 3.11, but was developed on Oleg's post-3.11 patches that
introduce exec_binprm().

2 files changed, 0 insertions, 5 deletions

diff --git a/kernel/audit.h b/kernel/audit.h
index e7b94ab66c49..b779642b29af 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -199,7 +199,6 @@ struct audit_context {
                 } mmap;
                 struct {
                         int                     argc;
-                        struct mm_struct        *mm;
                 } execve;
         };
         int fds[2];
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 425a8939be1a..dfc5d6745ee5 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1145,9 +1145,6 @@ static void audit_log_execve_info(struct audit_context *context,
         const char __user *p;
         char *buf;
 
-        if (context->execve.mm != current->mm)
-                return; /* execve failed, no additional info */
-
         p = (const char __user *)current->mm->arg_start;
 
         audit_log_format(*ab, "argc=%d", context->execve.argc);
@@ -2144,7 +2141,6 @@ void __audit_bprm(struct linux_binprm *bprm)
 
         context->type = AUDIT_EXECVE;
         context->execve.argc = bprm->argc;
-        context->execve.mm = bprm->mm;
 }