On 2018-04-27 14:44, Andreas J. Reichel wrote:
> From: Andreas Reichel <[email protected]>
>
> If a non-existing user variable is requested and a NULL-buffer is
> provided, the getter maps an invalid memory area to retrieve the needed
> buffer size.
> Fix this by checking if the data pointer is valid first before mapping
> anything and furthermore don't call the mapper if the variable is not
> found.
>
> Signed-off-by: Andreas Reichel <[email protected]>
> ---
> env/env_api_fat.c | 3 +++
> env/uservars.c | 16 +++++++++++++---
> include/uservars.h | 6 +++---
> 3 files changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/env/env_api_fat.c b/env/env_api_fat.c
> index 1705cb9..a86c05d 100644
> --- a/env/env_api_fat.c
> +++ b/env/env_api_fat.c
> @@ -287,6 +287,9 @@ int bgenv_get(BGENV *env, char *key, uint64_t *type, void
> *data,
> uint8_t *u;
> uint32_t size;
> u = bgenv_find_uservar(env->data->userdata, key);
> + if (!u) {
> + return -EINVAL;
> + }
> bgenv_map_uservar(u, NULL, NULL, NULL, NULL, &size);
Here, you do not check the new return code. OK, u can't be NULL anymore,
but then it has to be clear (comment) that we do not expect
bgenv_map_uservar to fail otherwise.
> return size;
> }
> diff --git a/env/uservars.c b/env/uservars.c
> index eff1cf8..3ad95c3 100644
> --- a/env/uservars.c
> +++ b/env/uservars.c
> @@ -14,8 +14,8 @@
> #include "env_api.h"
> #include "uservars.h"
>
> -void bgenv_map_uservar(uint8_t *udata, char **key, uint64_t *type, uint8_t
> **val,
> - uint32_t *record_size, uint32_t *data_size)
> +int bgenv_map_uservar(uint8_t *udata, char **key, uint64_t *type, uint8_t
> **val,
> + uint32_t *record_size, uint32_t *data_size)
> {
> /* Each user variable is encoded as follows:
> * |------------|--------------|---------------|----------------|
> @@ -38,6 +38,10 @@ void bgenv_map_uservar(uint8_t *udata, char **key,
> uint64_t *type, uint8_t **val
> uint64_t *var_type;
> uint8_t *data;
>
> + if (!udata) {
> + return -EINVAL;
> + }
> +
In the case above, this check is not needed. Why can't we make that
consistent: either do the NULL check on caller side in all cases of let
bgenv_map_uservar do it and evaluate its error in all cases?
> /* Get the key */
> var_key = (char *)udata;
> if (key) {
> @@ -68,6 +72,8 @@ void bgenv_map_uservar(uint8_t *udata, char **key, uint64_t
> *type, uint8_t **val
> if (val) {
> *val = data;
> }
> +
> + return 0;
> }
>
> void bgenv_serialize_uservar(uint8_t *p, char *key, uint64_t type, void
> *data,
> @@ -100,6 +106,7 @@ int bgenv_get_uservar(uint8_t *udata, char *key, uint64_t
> *type, void *data,
> char *lkey;
> uint32_t dsize;
> uint64_t ltype;
> + int res;
>
> uservar = bgenv_find_uservar(udata, key);
>
> @@ -107,7 +114,10 @@ int bgenv_get_uservar(uint8_t *udata, char *key,
> uint64_t *type, void *data,
> return -EINVAL;
> }
>
> - bgenv_map_uservar(uservar, &lkey, <ype, &value, NULL, &dsize);
> + res = bgenv_map_uservar(uservar, &lkey, <ype, &value, NULL, &dsize);
> + if (res) {
> + return res;
> + }
>
> if (dsize > maxlen) {
> dsize = maxlen;
> diff --git a/include/uservars.h b/include/uservars.h
> index b1d1d7c..012240c 100644
> --- a/include/uservars.h
> +++ b/include/uservars.h
> @@ -15,9 +15,9 @@
>
> #include <stdint.h>
>
> -void bgenv_map_uservar(uint8_t *udata, char **key, uint64_t *type,
> - uint8_t **val, uint32_t *record_size,
> - uint32_t *data_size);
> +int bgenv_map_uservar(uint8_t *udata, char **key, uint64_t *type,
> + uint8_t **val, uint32_t *record_size,
> + uint32_t *data_size);
> void bgenv_serialize_uservar(uint8_t *p, char *key, uint64_t type, void
> *data,
> uint32_t record_size);
>
>
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
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