From 0186f76569400a708a7ea638260f24f901e14029 Mon Sep 17 00:00:00 2001 From: Nikita Zhandarovich Date: Mon, 6 Mar 2023 08:06:56 -0800 Subject: [PATCH] x86/mm: Fix use of uninitialized buffer in sme_enable() commit cbebd68f59f03633469f3ecf9bea99cd6cce3854 upstream. cmdline_find_option() may fail before doing any initialization of the buffer array. This may lead to unpredictable results when the same buffer is used later in calls to strncmp() function. Fix the issue by returning early if cmdline_find_option() returns an error. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE. Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption") Signed-off-by: Nikita Zhandarovich Signed-off-by: Borislav Petkov (AMD) Acked-by: Tom Lendacky Cc: Link: https://lore.kernel.org/r/20230306160656.14844-1-n.zhandarovich@fintech.ru Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/mem_encrypt_identity.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index 700ce8fdea87c..c7e9fb1d830d2 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -585,7 +585,8 @@ void __init sme_enable(struct boot_params *bp) cmdline_ptr = (const char *)((u64)bp->hdr.cmd_line_ptr | ((u64)bp->ext_cmd_line_ptr << 32)); - cmdline_find_option(cmdline_ptr, cmdline_arg, buffer, sizeof(buffer)); + if (cmdline_find_option(cmdline_ptr, cmdline_arg, buffer, sizeof(buffer)) < 0) + return; if (!strncmp(buffer, cmdline_on, sizeof(buffer))) sme_me_mask = me_mask; -- 2.30.2