From: Nikita Zhandarovich n.zhandarovich@fintech.ru
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 n.zhandarovich@fintech.ru Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Acked-by: Tom Lendacky thomas.lendacky@amd.com Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230306160656.14844-1-n.zhandarovich@fintech.ru Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/mm/mem_encrypt_identity.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -579,7 +579,8 @@ void __init sme_enable(struct boot_param 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;