From: Markus Stockhausen Date: Sun, 25 Aug 2024 17:22:28 +0000 (-0400) Subject: realtek: 6.6: harden fw_init_cmdline() X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=dc9fca1fd19a31af4a0e3f1e3c93306ce4bca8b0;p=openwrt%2Fstaging%2Fxback.git realtek: 6.6: harden fw_init_cmdline() Some devices (e.g. HP JG924A) hand over other than expected kernel boot arguments. Looking at these one can see: fw_init_cmdline: fw_arg0=00020000 fw_init_cmdline: fw_arg1=00060000 fw_init_cmdline: fw_arg2=fffdffff fw_init_cmdline: fw_arg3=0000416c Especially fw_arg2 should be the pointer to the environment and it looks very suspicous. It is not aligned and the address is outside KSEG0 and KSEG1. Booting the device will result in a hang. Do better at verifying the address. Signed-off-by: Markus Stockhausen Suggested-by: Bjørn Mork --- diff --git a/target/linux/realtek/patches-6.6/320-harden-fw_init_cmdline.patch b/target/linux/realtek/patches-6.6/320-harden-fw_init_cmdline.patch new file mode 100644 index 0000000000..d45932b977 --- /dev/null +++ b/target/linux/realtek/patches-6.6/320-harden-fw_init_cmdline.patch @@ -0,0 +1,38 @@ +From e813f48461b8011244b3e7dfe118cf94fd595f0d Mon Sep 17 00:00:00 2001 +From: Markus Stockhausen +Date: Sun, 25 Aug 2024 13:09:48 -0400 +Subject: [PATCH] realtek: harden fw_init_cmdline() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Some devices (e.g. HP JG924A) hand over other than expected kernel boot +arguments. Looking at these one can see: + +fw_init_cmdline: fw_arg0=00020000 +fw_init_cmdline: fw_arg1=00060000 +fw_init_cmdline: fw_arg2=fffdffff +fw_init_cmdline: fw_arg3=0000416c + +Especially fw_arg2 should be the pointer to the environment and it looks +very suspicous. It is not aligned and the address is outside KSEG0 and +KSEG1. Booting the device will result in a hang. Do better at verifying +the address. + +Signed-off-by: Bjørn Mork +Signed-off-by: Markus Stockhausen +--- + arch/mips/fw/lib/cmdline.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/arch/mips/fw/lib/cmdline.c ++++ b/arch/mips/fw/lib/cmdline.c +@@ -31,7 +31,7 @@ void __init fw_init_cmdline(void) + } + + /* Validate environment pointer. */ +- if (fw_arg2 < CKSEG0) ++ if (fw_arg2 < CKSEG0 || fw_arg2 >= CKSEG2) + _fw_envp = NULL; + else + _fw_envp = (int *)fw_arg2;