From: John L. Hammond <john.hammond@intel.com>
Date: Wed, 13 Jan 2016 17:16:28 +0000 (-0600)
Subject: LU-7661 mgs: restrict MGS_SET_INFO to stripe parameters
X-Git-Tag: 2.7.66~31
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=ff577af11b3eb96fbdb2de7af0cdf78ad6c8ec56

LU-7661 mgs: restrict MGS_SET_INFO to stripe parameters

The MGS_SET_INFO RPC is only needed for setting the default striping
on a filesystem, so in mgs_set_info() reject attempts to set a
parameter that is not of the form *.lov.stripe{count,size,offset}=*.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I5ac693f886fd035ab639e03628849e791e1e2e9a
Reviewed-on: http://review.whamcloud.com/17982
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Jeremy Filizetti <jeremy.filizetti@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/mgs/mgs_handler.c b/lustre/mgs/mgs_handler.c
index 17cb290..316d963 100644
--- a/lustre/mgs/mgs_handler.c
+++ b/lustre/mgs/mgs_handler.c
@@ -94,11 +94,18 @@ static int mgs_exception(struct tgt_session_info *tsi)
 	RETURN(0);
 }
 
+static inline bool str_starts_with(const char *str, const char *prefix)
+{
+	return strncmp(str, prefix, strlen(prefix)) == 0;
+}
+
 static int mgs_set_info(struct tgt_session_info *tsi)
 {
 	struct mgs_thread_info	*mgi;
 	struct mgs_send_param	*msp, *rep_msp;
 	struct lustre_cfg	*lcfg;
+	size_t			 param_len;
+	char			*s;
 	int			 rc;
 
 	ENTRY;
@@ -111,6 +118,20 @@ static int mgs_set_info(struct tgt_session_info *tsi)
 	if (msp == NULL)
 		RETURN(err_serious(-EFAULT));
 
+	param_len = strnlen(msp->mgs_param, sizeof(msp->mgs_param));
+	if (param_len == 0 || param_len == sizeof(msp->mgs_param))
+		RETURN(-EINVAL);
+
+	/* We only allow '*.lov.stripe{size,count,offset}=*' from an RPC. */
+	s = strchr(msp->mgs_param, '.');
+	if (s == NULL)
+		RETURN(-EINVAL);
+
+	if (!str_starts_with(s + 1, "lov.stripesize=") &&
+	    !str_starts_with(s + 1, "lov.stripecount=") &&
+	    !str_starts_with(s + 1, "lov.stripeoffset="))
+		RETURN(-EINVAL);
+
 	/* Construct lustre_cfg structure to pass to function mgs_setparam */
 	lustre_cfg_bufs_reset(&mgi->mgi_bufs, NULL);
 	lustre_cfg_bufs_set_string(&mgi->mgi_bufs, 1, msp->mgs_param);