From 15a0b58ca43ccbae26d1a1e7718d7d8bd2c2add2 Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Sun, 8 Nov 2020 21:45:40 -0500 Subject: [PATCH 3/5] swtpm: Do not follow symlinks when opening lockfile (CVE-2020-28407) This patch addresses CVE-2020-28407. Prevent us from following symliks when we open the lockfile for writing. Signed-off-by: Stefan Berger --- src/swtpm/swtpm_nvfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/swtpm/swtpm_nvfile.c b/src/swtpm/swtpm_nvfile.c index 3b928d0..8a6621b 100644 --- a/src/swtpm/swtpm_nvfile.c +++ b/src/swtpm/swtpm_nvfile.c @@ -210,7 +210,7 @@ static TPM_RESULT SWTPM_NVRAM_Lock_Lockfile(const char *directory, return TPM_FAIL; } - *fd = open(lockfile, O_WRONLY|O_CREAT|O_TRUNC, 0660); + *fd = open(lockfile, O_WRONLY|O_CREAT|O_TRUNC|O_NOFOLLOW, 0660); if (*fd < 0) { logprintf(STDERR_FILENO, "SWTPM_NVRAM_Lock_Lockfile: Could not open lockfile: %s\n", -- 2.27.0