linux-kernel - [PATCH v3 1/4] kernfs: kvmalloc xattr value instead of kmalloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200312200317.31736-2-dxu@dxuuu.xyz>
Date:   Thu, 12 Mar 2020 13:03:14 -0700
From:   Daniel Xu <dxu@...uu.xyz>
To:     cgroups@...r.kernel.org, tj@...nel.org, lizefan@...wei.com,
        hannes@...xchg.org, viro@...iv.linux.org.uk
Cc:     Daniel Xu <dxu@...uu.xyz>, shakeelb@...gle.com,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        gregkh@...uxfoundation.org, kernel-team@...com
Subject: [PATCH v3 1/4] kernfs: kvmalloc xattr value instead of kmalloc

xattr values have a 64k maximum size. This can result in an order 4
kmalloc request which can be difficult to fulfill. Since xattrs do not
need physically contiguous memory, we can switch to kvmalloc and not
have to worry about higher order allocations failing.

Signed-off-by: Daniel Xu <dxu@...uu.xyz>
---
 fs/xattr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 90dd78f0eb27..0d3c9b4d1914 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -817,7 +817,7 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
 	if (len < sizeof(*new_xattr))
 		return NULL;
 
-	new_xattr = kmalloc(len, GFP_KERNEL);
+	new_xattr = kvmalloc(len, GFP_KERNEL);
 	if (!new_xattr)
 		return NULL;
 
@@ -882,7 +882,7 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 
 		new_xattr->name = kstrdup(name, GFP_KERNEL);
 		if (!new_xattr->name) {
-			kfree(new_xattr);
+			kvfree(new_xattr);
 			return -ENOMEM;
 		}
 	}
@@ -912,7 +912,7 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
 	spin_unlock(&xattrs->lock);
 	if (xattr) {
 		kfree(xattr->name);
-		kfree(xattr);
+		kvfree(xattr);
 	}
 	return err;
 
-- 
2.21.1