Default env variables on Espressobin boards are broken since commit c4df0f6f315c
("arm: mvebu: Espressobin: Set default value for $fdtfile env variable") as well
as the 'env default -a' command.The algorithm to find free space in the default_environment[] array returns after the first env variable instead of the correct position of the last variable, where there is allocated free space. This causes that U-Boot board_late_init() function to overwrite a portion of the default environment with $ethXaddr and $fdtfile variables immediately after the first env variable and so it is overwriting other variables. This patch also adds an additional null byte to terminate the environment array. But U-Boot board_late_init() function do not fill this nul byte explicitly. And because of that, U-Boot is later trying to interpret remaining buffer as a continuation of variable list. Normally buffer should be empty but due to the above issue, it contains garbage from remaining env variables. For example 'env default -a' command results in damaging variable names. It was observed that scritaddr variable name was changed to criptaddr (without leading 's'). This bug was reported and discussed on the Armbian forum: https://forum.armbian.com/topic/19564-making-espressobin-v7-work-in-2022/?do=findComment&comment=138136 Fix these issues in two steps: 1) Change code which finds free space for dynamic env variables in default_environment[] array by jumping to the end of the variable list instead of jumping after the first defined variable. [By Derek] 2) Add code which appends terminating nul byte as indication of the end of the env list, after the last nul term env string. [By Pali] Fixes: c4df0f6f315c ("arm: mvebu: Espressobin: Set default value for $fdtfile env variable") Signed-off-by: Derek LaHousse <de...@seaofdirac.org> Signed-off-by: Pali Rohár <p...@kernel.org> --- Changes in v3: - End of line wrap fix Changes in v2: - Include Pali's end-of-array null - Better tags - More documentation of what is fixed diff --git a/board/Marvell/mvebu_armada-37xx/board.c b/board/Marvell/mvebu_armada-37xx/board.c index c6ecc323bb99..44c72344e8be 100644 --- a/board/Marvell/mvebu_armada-37xx/board.c +++ b/board/Marvell/mvebu_armada-37xx/board.c @@ -99,9 +99,16 @@ int board_late_init(void) if (!of_machine_is_compatible("globalscale,espressobin")) return 0; - /* Find free buffer in default_environment[] for new variables */ - while (*ptr != '\0' && *(ptr+1) != '\0') ptr++; - ptr += 2; + /* + * Find free space for new variables in default_environment[] array. + * Free space is after the last variable, each variable is termined + * by nul byte and after the last variable is additional nul byte. + * Move ptr to the position where new variable can be filled. + */ + while (*ptr != '\0') { + do { ptr++; } while (*ptr != '\0'); + ptr++; + } /* * Ensure that 'env default -a' does not erase permanent MAC addresses @@ -145,6 +152,13 @@ int board_late_init(void) strcpy(ptr, "fdtfile=marvell/armada-3720-espressobin- emmc.dtb"); else strcpy(ptr, "fdtfile=marvell/armada-3720-espressobin.dtb"); + ptr += strlen(ptr) + 1; + + /* + * After the last variable (which is nul term string) append another nul + * byte which terminates the list. So everything after ptr is ignored. + */ + *ptr = '\0'; return 0; }
