1 files changed, 59 insertions, 25 deletions

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 9b77dca0b786..37b458a9af3a 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -109,22 +109,49 @@ static ssize_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
 	return ret;
 }
 
+/*
+ * The convention with strings in xattrs is that they should not be NULL
+ * terminated, since we're returning the length with them. snprintf always
+ * NULL terminates however, so call it on a temporary buffer and then memcpy
+ * the result into place.
+ */
+static int ceph_fmt_xattr(char *val, size_t size, const char *fmt, ...)
+{
+	int ret;
+	va_list args;
+	char buf[96]; /* NB: reevaluate size if new vxattrs are added */
+
+	va_start(args, fmt);
+	ret = vsnprintf(buf, size ? sizeof(buf) : 0, fmt, args);
+	va_end(args);
+
+	/* Sanity check */
+	if (size && ret + 1 > sizeof(buf)) {
+		WARN_ONCE(true, "Returned length too big (%d)", ret);
+		return -E2BIG;
+	}
+
+	if (ret <= size)
+		memcpy(val, buf, ret);
+	return ret;
+}
+
 static ssize_t ceph_vxattrcb_layout_stripe_unit(struct ceph_inode_info *ci,
 						char *val, size_t size)
 {
-	return snprintf(val, size, "%u", ci->i_layout.stripe_unit);
+	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.stripe_unit);
 }
 
 static ssize_t ceph_vxattrcb_layout_stripe_count(struct ceph_inode_info *ci,
 						 char *val, size_t size)
 {
-	return snprintf(val, size, "%u", ci->i_layout.stripe_count);
+	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.stripe_count);
 }
 
 static ssize_t ceph_vxattrcb_layout_object_size(struct ceph_inode_info *ci,
 						char *val, size_t size)
 {
-	return snprintf(val, size, "%u", ci->i_layout.object_size);
+	return ceph_fmt_xattr(val, size, "%u", ci->i_layout.object_size);
 }
 
 static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
@@ -138,10 +165,13 @@ static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
 
 	down_read(&osdc->lock);
 	pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
-	if (pool_name)
-		ret = snprintf(val, size, "%s", pool_name);
-	else
-		ret = snprintf(val, size, "%lld", pool);
+	if (pool_name) {
+		ret = strlen(pool_name);
+		if (ret <= size)
+			memcpy(val, pool_name, ret);
+	} else {
+		ret = ceph_fmt_xattr(val, size, "%lld", pool);
+	}
 	up_read(&osdc->lock);
 	return ret;
 }
@@ -149,10 +179,13 @@ static ssize_t ceph_vxattrcb_layout_pool(struct ceph_inode_info *ci,
 static ssize_t ceph_vxattrcb_layout_pool_namespace(struct ceph_inode_info *ci,
 						   char *val, size_t size)
 {
-	int ret = 0;
+	ssize_t ret = 0;
 	struct ceph_string *ns = ceph_try_get_string(ci->i_layout.pool_ns);
+
 	if (ns) {
-		ret = snprintf(val, size, "%.*s", ns->len, ns->str);
+		ret = ns->len;
+		if (ret <= size)
+			memcpy(val, ns->str, ret);
 		ceph_put_string(ns);
 	}
 	return ret;
@@ -163,50 +196,51 @@ static ssize_t ceph_vxattrcb_layout_pool_namespace(struct ceph_inode_info *ci,
 static ssize_t ceph_vxattrcb_dir_entries(struct ceph_inode_info *ci, char *val,
 					 size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_files + ci->i_subdirs);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_files + ci->i_subdirs);
 }
 
 static ssize_t ceph_vxattrcb_dir_files(struct ceph_inode_info *ci, char *val,
 				       size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_files);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_files);
 }
 
 static ssize_t ceph_vxattrcb_dir_subdirs(struct ceph_inode_info *ci, char *val,
 					 size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_subdirs);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_subdirs);
 }
 
 static ssize_t ceph_vxattrcb_dir_rentries(struct ceph_inode_info *ci, char *val,
 					  size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_rfiles + ci->i_rsubdirs);
+	return ceph_fmt_xattr(val, size, "%lld",
+				ci->i_rfiles + ci->i_rsubdirs);
 }
 
 static ssize_t ceph_vxattrcb_dir_rfiles(struct ceph_inode_info *ci, char *val,
 					size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_rfiles);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_rfiles);
 }
 
 static ssize_t ceph_vxattrcb_dir_rsubdirs(struct ceph_inode_info *ci, char *val,
 					  size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_rsubdirs);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_rsubdirs);
 }
 
 static ssize_t ceph_vxattrcb_dir_rbytes(struct ceph_inode_info *ci, char *val,
 					size_t size)
 {
-	return snprintf(val, size, "%lld", ci->i_rbytes);
+	return ceph_fmt_xattr(val, size, "%lld", ci->i_rbytes);
 }
 
 static ssize_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
 					size_t size)
 {
-	return snprintf(val, size, "%lld.%09ld", ci->i_rctime.tv_sec,
-			ci->i_rctime.tv_nsec);
+	return ceph_fmt_xattr(val, size, "%lld.%09ld", ci->i_rctime.tv_sec,
+				ci->i_rctime.tv_nsec);
 }
 
 /* dir pin */
@@ -218,7 +252,7 @@ static bool ceph_vxattrcb_dir_pin_exists(struct ceph_inode_info *ci)
 static ssize_t ceph_vxattrcb_dir_pin(struct ceph_inode_info *ci, char *val,
 				     size_t size)
 {
-	return snprintf(val, size, "%d", (int)ci->i_dir_pin);
+	return ceph_fmt_xattr(val, size, "%d", (int)ci->i_dir_pin);
 }
 
 /* quotas */
@@ -238,20 +272,20 @@ static bool ceph_vxattrcb_quota_exists(struct ceph_inode_info *ci)
 static ssize_t ceph_vxattrcb_quota(struct ceph_inode_info *ci, char *val,
 				   size_t size)
 {
-	return snprintf(val, size, "max_bytes=%llu max_files=%llu",
-			ci->i_max_bytes, ci->i_max_files);
+	return ceph_fmt_xattr(val, size, "max_bytes=%llu max_files=%llu",
+				ci->i_max_bytes, ci->i_max_files);
 }
 
 static ssize_t ceph_vxattrcb_quota_max_bytes(struct ceph_inode_info *ci,
 					     char *val, size_t size)
 {
-	return snprintf(val, size, "%llu", ci->i_max_bytes);
+	return ceph_fmt_xattr(val, size, "%llu", ci->i_max_bytes);
 }
 
 static ssize_t ceph_vxattrcb_quota_max_files(struct ceph_inode_info *ci,
 					     char *val, size_t size)
 {
-	return snprintf(val, size, "%llu", ci->i_max_files);
+	return ceph_fmt_xattr(val, size, "%llu", ci->i_max_files);
 }
 
 /* snapshots */
@@ -263,8 +297,8 @@ static bool ceph_vxattrcb_snap_btime_exists(struct ceph_inode_info *ci)
 static ssize_t ceph_vxattrcb_snap_btime(struct ceph_inode_info *ci, char *val,
 					size_t size)
 {
-	return snprintf(val, size, "%lld.%09ld", ci->i_snap_btime.tv_sec,
-			ci->i_snap_btime.tv_nsec);
+	return ceph_fmt_xattr(val, size, "%lld.%09ld", ci->i_snap_btime.tv_sec,
+				ci->i_snap_btime.tv_nsec);
 }
 
 #define CEPH_XATTR_NAME(_type, _name)	XATTR_CEPH_PREFIX #_type "." #_name