On 2022/5/26 9:06, Jarkko Sakkinen wrote:
On Wed, 2022-05-25 at 09:26 +0800, GUO Zihua wrote:
Use struct_size helper for calculating size of flexible struct, following
the best practice.
Note: HASH_SIZE here is a SHA256_DIGEST_SIZE whoes value is 32, so
~~~~~
adding 1 should be fine here.
Where? '1' is without a context. I don't really know how to interpret
this sentence.
Hi Jarkko,
The original code computes the size for kzalloc with open-coded
HASH_SIZE + 1. Although the best practice for size computation suggest
that we should be using size_add(). I figure it's a bit redundant here
as the purpose of size_add() is to avoid size overflow and adding 32
with 1 will not trigger a size overflow.
Maybe I should just use size_add() anyway? Please lemme know and I'll
update the patch or the commit message.
Link: https://lore.kernel.org/all/CAHk-=wiGWjxs7EVUpccZEi6esvjpHJdgHQ=vtUeJ5crL62hx9A@xxxxxxxxxxxxxx/
Signed-off-by: GUO Zihua <guozihua@xxxxxxxxxx>
---
v3:
Update commit message format according to Jarkko's feedback.
v2:
Update the commit message, removing the part about "potential issue"
following Jarkko's suggestion.
---
security/keys/encrypted-keys/encrypted.c | 7 +++++--
security/keys/user_defined.c | 2 +-
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index e05cfc2e49ae..37349580e855 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -613,6 +613,7 @@ static struct encrypted_key_payload *encrypted_key_alloc(struct key *key,
long dlen;
int i;
int ret;
+ size_t epayload_datalen = 0;
ret = kstrtol(datalen, 10, &dlen);
if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE)
@@ -667,8 +668,10 @@ static struct encrypted_key_payload *encrypted_key_alloc(struct key *key,
if (ret < 0)
return ERR_PTR(ret);
- epayload = kzalloc(sizeof(*epayload) + payload_datalen +
- datablob_len + HASH_SIZE + 1, GFP_KERNEL);
+ epayload_datalen = size_add(payload_datalen, datablob_len);
+ epayload_datalen = size_add(epayload_datalen, HASH_SIZE + 1);
BTW, the "here" is here.
+ epayload = kzalloc(struct_size(epayload, payload_data,
+ epayload_datalen), GFP_KERNEL);
if (!epayload)
return ERR_PTR(-ENOMEM);
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 749e2a4dcb13..334fed36e9f3 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -64,7 +64,7 @@ int user_preparse(struct key_preparsed_payload *prep)
if (datalen <= 0 || datalen > 32767 || !prep->data)
return -EINVAL;
- upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+ upayload = kmalloc(struct_size(upayload, data, datalen), GFP_KERNEL);
if (!upayload)
return -ENOMEM;
BR, Jarkko
--
Best
GUO Zihua
