[PATCH] hfsplus: fix uninit-value in hfsplus_listxattr

[Edward Adam Davis]

[syzbot reported]
BUG: KMSAN: uninit-value in strncmp+0x11e/0x180 lib/string.c:291
 strncmp+0x11e/0x180 lib/string.c:291
 hfsplus_listxattr+0x97d/0x1a60
 vfs_listxattr fs/xattr.c:493 [inline]
 listxattr+0x1f3/0x6b0 fs/xattr.c:840
 path_listxattr fs/xattr.c:864 [inline]
 __do_sys_listxattr fs/xattr.c:876 [inline]
 __se_sys_listxattr fs/xattr.c:873 [inline]
 __x64_sys_listxattr+0x16b/0x2f0 fs/xattr.c:873
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3804 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmalloc_trace+0x578/0xba0 mm/slub.c:3992
 kmalloc include/linux/slab.h:628 [inline]
 hfsplus_listxattr+0x4cc/0x1a60 fs/hfsplus/xattr.c:701
 vfs_listxattr fs/xattr.c:493 [inline]
 listxattr+0x1f3/0x6b0 fs/xattr.c:840
 path_listxattr fs/xattr.c:864 [inline]
 __do_sys_listxattr fs/xattr.c:876 [inline]
 __se_sys_listxattr fs/xattr.c:873 [inline]
 __x64_sys_listxattr+0x16b/0x2f0 fs/xattr.c:873
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a
[Fix]
When allocating memory to strbuf, initialize memory to 0.

Reported-and-tested-by: syzbot+01ade747b16e9c8030e0@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 fs/hfsplus/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 9c9ff6b8c6f7..858029b1c173 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -698,7 +698,7 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
 		return err;
 	}
 
-	strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
+	strbuf = kzalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
 			XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
 	if (!strbuf) {
 		res = -ENOMEM;
-- 
2.43.0