x86/intel_rdt: Return error for incorrect resource names in schemata

4797b7df · Vikas Shivappa <[email protected]> · 2017-04-19 16:50:04 -07:00

When schemata parses the resource names it does not return an error if it
detects incorrect resource names and fails quietly.

This happens because for_each_enabled_rdt_resource(r) leaves "r" pointing
beyond the end of the rdt_resources_all[] array, and the check for !r->name
results in an out of bounds access.

Split the resource parsing part into a helper function to avoid the issue.

[ tglx: Made it readable by splitting the parser loop out into a function ]

Reported-by: Prakhya, Sai Praneeth <[email protected]>
Signed-off-by: Vikas Shivappa <[email protected]>
Tested-by: Prakhya, Sai Praneeth <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

Commit: 4797b7dfdfcf457075c36743d71e2b0feeaaa20f
Parents: 634b0e04

Changes

1 files changed · +15 −13

File	Status	Add	Del	Content
arch/x86/kernel/cpu/intel_rdt_schemata.c	modified	+15	−13	View file

arch/x86/kernel/cpu/intel_rdt_schemata.c

View file

diff --git a/arch/x86/kernel/cpu/intel_rdt_schemata.c b/arch/x86/kernel/cpu/intel_rdt_schemata.c
index e64b2cf..406d7a6 100644
--- a/arch/x86/kernel/cpu/intel_rdt_schemata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_schemata.c
@@ -188,6 +188,17 @@ done:
 	return 0;
 }
 
+static int rdtgroup_parse_resource(char *resname, char *tok, int closid)
+{
+	struct rdt_resource *r;
+
+	for_each_enabled_rdt_resource(r) {
+		if (!strcmp(resname, r->name) && closid < r->num_closid)
+			return parse_line(tok, r);
+	}
+	return -EINVAL;
+}
+
 ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
 				char *buf, size_t nbytes, loff_t off)
 {
@@ -210,9 +221,10 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
 
 	closid = rdtgrp->closid;
 
-	for_each_enabled_rdt_resource(r)
+	for_each_enabled_rdt_resource(r) {
 		list_for_each_entry(dom, &r->domains, list)
 			dom->have_new_ctrl = false;
+	}
 
 	while ((tok = strsep(&buf, "\n")) != NULL) {
 		resname = strim(strsep(&tok, ":"));
@@ -220,19 +232,9 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
 			ret = -EINVAL;
 			goto out;
 		}
-		for_each_enabled_rdt_resource(r) {
-			if (!strcmp(resname, r->name) &&
-			    closid < r->num_closid) {
-				ret = parse_line(tok, r);
-				if (ret)
-					goto out;
-				break;
-			}
-		}
-		if (!r->name) {
-			ret = -EINVAL;
+		ret = rdtgroup_parse_resource(resname, tok, closid);
+		if (ret)
 			goto out;
-		}
 	}
 
 	for_each_enabled_rdt_resource(r) {