From patchwork Tue Jul 7 18:51:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 240890 List-Id: U-Boot discussion From: marex at denx.de (Marek Vasut) Date: Tue, 7 Jul 2020 20:51:38 +0200 Subject: [PATCH V2 6/7] env: Add option to only ever append environment In-Reply-To: <20200707185139.2225-1-marex@denx.de> References: <20200707185139.2225-1-marex@denx.de> Message-ID: <20200707185139.2225-6-marex@denx.de> Add configuration option which prevents the environment hash table to be ever cleared and reloaded with different content. This is useful in case the first environment loaded into the hash table contains e.g. sensitive content which must not be dropped or reloaded. Signed-off-by: Marek Vasut Reviewed-by: Tom Rini --- V2: No change --- env/Kconfig | 9 +++++++++ env/env.c | 2 ++ lib/hashtable.c | 4 ++++ 3 files changed, 15 insertions(+) diff --git a/env/Kconfig b/env/Kconfig index 38e7fadbb9..9f7eff4f69 100644 --- a/env/Kconfig +++ b/env/Kconfig @@ -604,6 +604,15 @@ config DELAY_ENVIRONMENT later by U-Boot code. With CONFIG_OF_CONTROL this is instead controlled by the value of /config/load-environment. +config ENV_APPEND + bool "Always append the environment with new data" + default n + help + If defined, the environment hash table is only ever appended with new + data, but the existing hash table can never be dropped and reloaded + with newly imported data. This may be used in combination with static + flags to e.g. to protect variables which must not be modified. + config ENV_ACCESS_IGNORE_FORCE bool "Block forced environment operations" default n diff --git a/env/env.c b/env/env.c index 024d36fdbe..967a9d36d7 100644 --- a/env/env.c +++ b/env/env.c @@ -204,7 +204,9 @@ int env_load(void) ret = drv->load(); if (!ret) { printf("OK\n"); +#if !CONFIG_IS_ENABLED(ENV_APPEND) return 0; +#endif } else if (ret == -ENOMSG) { /* Handle "bad CRC" case */ if (best_prio == -1) diff --git a/lib/hashtable.c b/lib/hashtable.c index 7b6781bc35..ef834badc5 100644 --- a/lib/hashtable.c +++ b/lib/hashtable.c @@ -826,6 +826,10 @@ int himport_r(struct hsearch_data *htab, if (nvars) memcpy(localvars, vars, sizeof(vars[0]) * nvars); +#if CONFIG_IS_ENABLED(ENV_APPEND) + flag |= H_NOCLEAR; +#endif + if ((flag & H_NOCLEAR) == 0 && !nvars) { /* Destroy old hash table if one exists */ debug("Destroy Hash Table: %p table = %p\n", htab,