audit: rework execve audit
The purpose of audit_bprm() is to log the argv array to a userspace daemon at
the end of the execve system call. Since user-space hasn't had time to run,
this array is still in pristine state on the process' stack; so no need to
copy it, we can just grab it from there.
In order to minimize the damage to audit_log_*() copy each string into a
temporary kernel buffer first.
Currently the audit code requires that the full argument vector fits in a
single packet. So currently it does clip the argv size to a (sysctl) limit,
but only when execve auditing is enabled.
If the audit protocol gets extended to allow for multiple packets this check
can be removed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ollie Wild <aaw@google.com>
Cc: <linux-audit@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index ebffdff..72e247ef 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1065,6 +1065,13 @@
resume it if we have a value of 3 or more percent; consider information about
the amount of free space valid for 30 seconds
+audit_argv_kb
+-------------
+
+The file contains a single value denoting the limit on the argv array size
+for execve (in KiB). This limit is only applied when system call auditing for
+execve is enabled, otherwise the value is ignored.
+
ctrl-alt-del
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