From b50eba7e2d534762a19a7207dda012f09302a8d2 Mon Sep 17 00:00:00 2001 From: Richard Guy Briggs Date: Mon, 16 Sep 2013 18:20:42 -0400 Subject: [PATCH] audit: format user messages to size of MAX_AUDIT_MESSAGE_LENGTH Messages of type AUDIT_USER_TTY were being formatted to 1024 octets, truncating messages approaching MAX_AUDIT_MESSAGE_LENGTH (8970 octets). Set the formatting to 8560 characters, given maximum estimates for prefix and suffix budgets. See the problem discussion: https://www.redhat.com/archives/linux-audit/2009-January/msg00030.html And the new size rationale: https://www.redhat.com/archives/linux-audit/2013-September/msg00016.html Test ~8k messages with: auditctl -m "$(for i in $(seq -w 001 820);do echo -n "${i}0______";done)" Reported-by: LC Bruzenak Reported-by: Justin Stephenson Signed-off-by: Richard Guy Briggs Signed-off-by: Eric Paris --- include/uapi/linux/audit.h | 6 ++++++ kernel/audit.c | 3 ++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 75cef3fd97add2..5dfcd85037e2c6 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -358,6 +358,12 @@ enum { #define AUDIT_PERM_READ 4 #define AUDIT_PERM_ATTR 8 +/* MAX_AUDIT_MESSAGE_LENGTH is set in audit:lib/libaudit.h as: + * 8970 // PATH_MAX*2+CONTEXT_SIZE*2+11+256+1 + * max header+body+tailer: 44 + 29 + 32 + 262 + 7 + pad + */ +#define AUDIT_MESSAGE_TEXT_MAX 8560 + struct audit_status { __u32 mask; /* Bit mask for valid entries */ __u32 enabled; /* 1 = enabled, 0 = disabled */ diff --git a/kernel/audit.c b/kernel/audit.c index 91e53d04b6a9e8..dd63d2f978d5c3 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -715,7 +715,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) } audit_log_common_recv_msg(&ab, msg_type); if (msg_type != AUDIT_USER_TTY) - audit_log_format(ab, " msg='%.1024s'", + audit_log_format(ab, " msg='%.*s'", + AUDIT_MESSAGE_TEXT_MAX, (char *)data); else { int size;