From: Giel van Schijndel Subject: [PATCH] Use memzero_explicit to clear local buffers Date: Sun, 4 Jan 2015 19:05:40 +0100 Message-ID: <1420394744-20268-1-git-send-email-me@mortis.eu> Cc: Giel van Schijndel , Herbert Xu , "David S. Miller" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org (maintainer:X86 ARCHITECTURE...), Greg Kroah-Hartman , Steve French , Rahul Bedarkar , Thomas Pugliese , Randy Dunlap , Julia Lawall , linux-crypto@vger.kernel.org (open list:CRYPTO API), linux-usb@vger.kernel.org (open list:CERTIFIED WIRELES...), linux-cifs@vger.kernel.org (open list:COMMON INTERNET F...), samba-technical@lists.samba.org (moderated list:COMMON INTERNET F...) To: linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org When leaving a function use memzero_explicit instead of memset(0) to clear locally allocated/owned buffers. memset(0) may be optimized away. All of the affected buffers contain sensitive data, key material or derivatives of one of those two. --- arch/x86/crypto/sha256_ssse3_glue.c | 2 +- drivers/usb/wusbcore/security.c | 2 +- fs/cifs/smbencrypt.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/crypto/sha256_ssse3_glue.c b/arch/x86/crypto/sha256_ssse3_glue.c index 8fad72f..b616e63 100644 --- a/arch/x86/crypto/sha256_ssse3_glue.c +++ b/arch/x86/crypto/sha256_ssse3_glue.c @@ -164,7 +164,7 @@ static int sha256_ssse3_final(struct shash_desc *desc, u8 *out) dst[i] = cpu_to_be32(sctx->state[i]); /* Wipe context */ - memset(sctx, 0, sizeof(*sctx)); + memzero_explicit(sctx, sizeof(*sctx)); return 0; } diff --git a/drivers/usb/wusbcore/security.c b/drivers/usb/wusbcore/security.c index b66faaf..a25f4fe 100644 --- a/drivers/usb/wusbcore/security.c +++ b/drivers/usb/wusbcore/security.c @@ -521,7 +521,7 @@ error_wusbhc_set_ptk: error_hs3: error_hs2: error_hs1: - memset(hs, 0, 3*sizeof(hs[0])); + memzero_explicit(hs, 3*sizeof(hs[0])); memzero_explicit(&keydvt_out, sizeof(keydvt_out)); memzero_explicit(&keydvt_in, sizeof(keydvt_in)); memzero_explicit(&ccm_n, sizeof(ccm_n)); diff --git a/fs/cifs/smbencrypt.c b/fs/cifs/smbencrypt.c index 6c15663..a4232ec 100644 --- a/fs/cifs/smbencrypt.c +++ b/fs/cifs/smbencrypt.c @@ -221,7 +221,7 @@ E_md4hash(const unsigned char *passwd, unsigned char *p16, } rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16)); - memset(wpwd, 0, 129 * sizeof(__le16)); + memzero_explicit(wpwd, sizeof(wpwd)); return rc; } -- 2.1.4