2023-01-27 20:12:47

by Rae Moar

Subject: [PATCH v1] apparmor: fix use of strcpy in policy_unpack_test

Replace the use of strcpy() in build_aa_ext_struct() in
policy_unpack_test.c with strscpy().

strscpy() is the safer method to use to ensure the buffer does not
overflow. This was found by kernel test robot:
https://lore.kernel.org/all/[email protected]/.

Reported-by: kernel test robot <[email protected]>

Signed-off-by: Rae Moar <[email protected]>
---

Note: This patch is based on the apparmor-next branch. However, the
patch should also apply cleanly to the kselftest/kunit branch.

security/apparmor/policy_unpack_test.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/security/apparmor/policy_unpack_test.c b/security/apparmor/policy_unpack_test.c
index e1bfdab524b7..5c9bde25e56d 100644
--- a/security/apparmor/policy_unpack_test.c
+++ b/security/apparmor/policy_unpack_test.c
@@ -69,31 +69,30 @@ static struct aa_ext *build_aa_ext_struct(struct policy_unpack_fixture *puf,

*buf = AA_NAME;
*(buf + 1) = strlen(TEST_STRING_NAME) + 1;
- strcpy(buf + 3, TEST_STRING_NAME);
+ strscpy(buf + 3, TEST_STRING_NAME, e->end - (void *)(buf + 3));

buf = e->start + TEST_STRING_BUF_OFFSET;
*buf = AA_STRING;
*(buf + 1) = strlen(TEST_STRING_DATA) + 1;
- strcpy(buf + 3, TEST_STRING_DATA);
-
+ strscpy(buf + 3, TEST_STRING_DATA, e->end - (void *)(buf + 3));
buf = e->start + TEST_NAMED_U32_BUF_OFFSET;
*buf = AA_NAME;
*(buf + 1) = strlen(TEST_U32_NAME) + 1;
- strcpy(buf + 3, TEST_U32_NAME);
+ strscpy(buf + 3, TEST_U32_NAME, e->end - (void *)(buf + 3));
*(buf + 3 + strlen(TEST_U32_NAME) + 1) = AA_U32;
*((u32 *)(buf + 3 + strlen(TEST_U32_NAME) + 2)) = TEST_U32_DATA;

buf = e->start + TEST_NAMED_U64_BUF_OFFSET;
*buf = AA_NAME;
*(buf + 1) = strlen(TEST_U64_NAME) + 1;
- strcpy(buf + 3, TEST_U64_NAME);
+ strscpy(buf + 3, TEST_U64_NAME, e->end - (void *)(buf + 3));
*(buf + 3 + strlen(TEST_U64_NAME) + 1) = AA_U64;
*((u64 *)(buf + 3 + strlen(TEST_U64_NAME) + 2)) = TEST_U64_DATA;

buf = e->start + TEST_NAMED_BLOB_BUF_OFFSET;
*buf = AA_NAME;
*(buf + 1) = strlen(TEST_BLOB_NAME) + 1;
- strcpy(buf + 3, TEST_BLOB_NAME);
+ strscpy(buf + 3, TEST_BLOB_NAME, e->end - (void *)(buf + 3));
*(buf + 3 + strlen(TEST_BLOB_NAME) + 1) = AA_BLOB;
*(buf + 3 + strlen(TEST_BLOB_NAME) + 2) = TEST_BLOB_DATA_SIZE;
memcpy(buf + 3 + strlen(TEST_BLOB_NAME) + 6,
@@ -102,7 +101,7 @@ static struct aa_ext *build_aa_ext_struct(struct policy_unpack_fixture *puf,
buf = e->start + TEST_NAMED_ARRAY_BUF_OFFSET;
*buf = AA_NAME;
*(buf + 1) = strlen(TEST_ARRAY_NAME) + 1;
- strcpy(buf + 3, TEST_ARRAY_NAME);
+ strscpy(buf + 3, TEST_ARRAY_NAME, e->end - (void *)(buf + 3));
*(buf + 3 + strlen(TEST_ARRAY_NAME) + 1) = AA_ARRAY;
*((u16 *)(buf + 3 + strlen(TEST_ARRAY_NAME) + 2)) = TEST_ARRAY_SIZE;


base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2
--
2.39.1.456.gfc5497dd1b-goog

2023-01-30 20:48:19

by John Johansen

Subject: Re: [PATCH v1] apparmor: fix use of strcpy in policy_unpack_test

On 1/27/23 12:12, Rae Moar wrote:
> Replace the use of strcpy() in build_aa_ext_struct() in
> policy_unpack_test.c with strscpy().
>
> strscpy() is the safer method to use to ensure the buffer does not
> overflow. This was found by kernel test robot:
> https://lore.kernel.org/all/[email protected]/.
>
> Reported-by: kernel test robot <[email protected]>
>
> Signed-off-by: Rae Moar <[email protected]>

lgtm

I have pulled this into apparmor-next

> ---
>
> Note: This patch is based on the apparmor-next branch. However, the
> patch should also apply cleanly to the kselftest/kunit branch.
>
> security/apparmor/policy_unpack_test.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/security/apparmor/policy_unpack_test.c b/security/apparmor/policy_unpack_test.c
> index e1bfdab524b7..5c9bde25e56d 100644
> --- a/security/apparmor/policy_unpack_test.c
> +++ b/security/apparmor/policy_unpack_test.c
> @@ -69,31 +69,30 @@ static struct aa_ext *build_aa_ext_struct(struct policy_unpack_fixture *puf,
>
> *buf = AA_NAME;
> *(buf + 1) = strlen(TEST_STRING_NAME) + 1;
> - strcpy(buf + 3, TEST_STRING_NAME);
> + strscpy(buf + 3, TEST_STRING_NAME, e->end - (void *)(buf + 3));
>
> buf = e->start + TEST_STRING_BUF_OFFSET;
> *buf = AA_STRING;
> *(buf + 1) = strlen(TEST_STRING_DATA) + 1;
> - strcpy(buf + 3, TEST_STRING_DATA);
> -
> + strscpy(buf + 3, TEST_STRING_DATA, e->end - (void *)(buf + 3));
> buf = e->start + TEST_NAMED_U32_BUF_OFFSET;
> *buf = AA_NAME;
> *(buf + 1) = strlen(TEST_U32_NAME) + 1;
> - strcpy(buf + 3, TEST_U32_NAME);
> + strscpy(buf + 3, TEST_U32_NAME, e->end - (void *)(buf + 3));
> *(buf + 3 + strlen(TEST_U32_NAME) + 1) = AA_U32;
> *((u32 *)(buf + 3 + strlen(TEST_U32_NAME) + 2)) = TEST_U32_DATA;
>
> buf = e->start + TEST_NAMED_U64_BUF_OFFSET;
> *buf = AA_NAME;
> *(buf + 1) = strlen(TEST_U64_NAME) + 1;
> - strcpy(buf + 3, TEST_U64_NAME);
> + strscpy(buf + 3, TEST_U64_NAME, e->end - (void *)(buf + 3));
> *(buf + 3 + strlen(TEST_U64_NAME) + 1) = AA_U64;
> *((u64 *)(buf + 3 + strlen(TEST_U64_NAME) + 2)) = TEST_U64_DATA;
>
> buf = e->start + TEST_NAMED_BLOB_BUF_OFFSET;
> *buf = AA_NAME;
> *(buf + 1) = strlen(TEST_BLOB_NAME) + 1;
> - strcpy(buf + 3, TEST_BLOB_NAME);
> + strscpy(buf + 3, TEST_BLOB_NAME, e->end - (void *)(buf + 3));
> *(buf + 3 + strlen(TEST_BLOB_NAME) + 1) = AA_BLOB;
> *(buf + 3 + strlen(TEST_BLOB_NAME) + 2) = TEST_BLOB_DATA_SIZE;
> memcpy(buf + 3 + strlen(TEST_BLOB_NAME) + 6,
> @@ -102,7 +101,7 @@ static struct aa_ext *build_aa_ext_struct(struct policy_unpack_fixture *puf,
> buf = e->start + TEST_NAMED_ARRAY_BUF_OFFSET;
> *buf = AA_NAME;
> *(buf + 1) = strlen(TEST_ARRAY_NAME) + 1;
> - strcpy(buf + 3, TEST_ARRAY_NAME);
> + strscpy(buf + 3, TEST_ARRAY_NAME, e->end - (void *)(buf + 3));
> *(buf + 3 + strlen(TEST_ARRAY_NAME) + 1) = AA_ARRAY;
> *((u16 *)(buf + 3 + strlen(TEST_ARRAY_NAME) + 2)) = TEST_ARRAY_SIZE;
>
>
> base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2