[PATCH 27/32] KEYS: Use mem_to_flex_dup() with struct user_key_payload
From: Kees Cook <hidden>
Date: 2022-05-04 01:58:56
Also in:
keyrings, linux-arm-msm, linux-bluetooth, linux-devicetree, linux-hardening, linux-hyperv, linux-integrity, linux-rdma, linux-scsi, linux-security-module, linux-usb, linux-wireless, llvm, selinux, xen-devel
Subsystem:
keys/keyrings, security subsystem, the rest · Maintainers:
David Howells, Jarkko Sakkinen, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
As part of the work to perform bounds checking on all memcpy() uses, replace the open-coded a deserialization of bytes out of memory into a trailing flexible array by using a flex_array.h helper to perform the allocation, bounds checking, and copying. Cc: David Howells <dhowells@redhat.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Kees Cook <redacted> --- include/keys/user-type.h | 4 ++-- security/keys/user_defined.c | 7 ++----- 2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index 386c31432789..4e67ff902a32 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h@@ -26,8 +26,8 @@ */ struct user_key_payload { struct rcu_head rcu; /* RCU destructor */ - unsigned short datalen; /* length of this data */ - char data[] __aligned(__alignof__(u64)); /* actual data */ + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(unsigned short, datalen); + DECLARE_FLEX_ARRAY_ELEMENTS(char, data) __aligned(__alignof__(u64)); }; extern struct key_type key_type_user;
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 749e2a4dcb13..2fb84894cdaa 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c@@ -58,21 +58,18 @@ EXPORT_SYMBOL_GPL(key_type_logon); */ int user_preparse(struct key_preparsed_payload *prep) { - struct user_key_payload *upayload; + struct user_key_payload *upayload = NULL; size_t datalen = prep->datalen; if (datalen <= 0 || datalen > 32767 || !prep->data) return -EINVAL; - upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); - if (!upayload) + if (mem_to_flex_dup(&upayload, prep->data, datalen, GFP_KERNEL)) return -ENOMEM; /* attach the data */ prep->quotalen = datalen; prep->payload.data[0] = upayload; - upayload->datalen = datalen; - memcpy(upayload->data, prep->data, datalen); return 0; } EXPORT_SYMBOL_GPL(user_preparse);
--
2.32.0