From 1b89954a71e14056a4aa9192b562f3f0e23ce326 Mon Sep 17 00:00:00 2001 From: Joseph Sutton Date: Wed, 12 Oct 2022 13:57:13 +1300 Subject: [PATCH] gsskrb5: CVE-2022-3437 Use constant-time memcmp() for arcfour unwrap Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=15134 Signed-off-by: Joseph Sutton Reviewed-by: Andrew Bartlett --- lib/gssapi/krb5/arcfour.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/lib/gssapi/krb5/arcfour.c b/lib/gssapi/krb5/arcfour.c index e6d1f2403191..e838d007a4e4 100644 --- a/lib/gssapi/krb5/arcfour.c +++ b/lib/gssapi/krb5/arcfour.c @@ -365,7 +365,7 @@ _gssapi_verify_mic_arcfour(OM_uint32 * minor_status, return GSS_S_FAILURE; } - cmp = ct_memcmp(cksum_data, p + 8, 8); + cmp = (ct_memcmp(cksum_data, p + 8, 8) == 0); if (cmp) { *minor_status = 0; return GSS_S_BAD_MIC; @@ -385,9 +385,9 @@ _gssapi_verify_mic_arcfour(OM_uint32 * minor_status, _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number); if (context_handle->more_flags & LOCAL) - cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4); + cmp = (ct_memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4) != 0); else - cmp = (memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4) != 0); + cmp = (ct_memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4) != 0); memset_s(SND_SEQ, sizeof(SND_SEQ), 0, sizeof(SND_SEQ)); if (cmp != 0) { @@ -656,9 +656,9 @@ OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status, _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number); if (context_handle->more_flags & LOCAL) - cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4); + cmp = (ct_memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4) != 0); else - cmp = (memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4) != 0); + cmp = (ct_memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4) != 0); if (cmp != 0) { *minor_status = 0; @@ -730,7 +730,7 @@ OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status, return GSS_S_FAILURE; } - cmp = ct_memcmp(cksum_data, p0 + 16, 8); /* SGN_CKSUM */ + cmp = (ct_memcmp(cksum_data, p0 + 16, 8) == 0); /* SGN_CKSUM */ if (cmp) { _gsskrb5_release_buffer(minor_status, output_message_buffer); *minor_status = 0; @@ -1272,9 +1272,9 @@ _gssapi_unwrap_iov_arcfour(OM_uint32 *minor_status, _gsskrb5_decode_be_om_uint32(snd_seq, &seq_number); if (ctx->more_flags & LOCAL) { - cmp = memcmp(&snd_seq[4], "\xff\xff\xff\xff", 4); + cmp = (ct_memcmp(&snd_seq[4], "\xff\xff\xff\xff", 4) != 0); } else { - cmp = (memcmp(&snd_seq[4], "\x00\x00\x00\x00", 4) != 0); + cmp = (ct_memcmp(&snd_seq[4], "\x00\x00\x00\x00", 4) != 0); } if (cmp != 0) { *minor_status = 0; -- 2.38.1