From: Nikita Zhandarovich n.zhandarovich@fintech.ru
stable inclusion from stable-v4.19.279 commit ffdf8d81c48822a329af9f31dc239090f4a60761 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6TIG1 CVE: NA
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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 Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- 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 4cbaacbe889a..0fadc69d2621 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -563,7 +563,8 @@ 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;