57 lines
2.2 KiB
Diff
57 lines
2.2 KiB
Diff
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From 423a5d56274a1d343e0d2107dfc4fbf0df2dcca5 Mon Sep 17 00:00:00 2001
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From: Tobias Brunner <tobias@strongswan.org>
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Date: Tue, 28 Sep 2021 17:52:08 +0200
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Subject: [PATCH] Reject RSASSA-PSS params with negative salt length
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The `salt_len` member in the struct is of type `ssize_t` because we use
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negative values for special automatic salt lengths when generating
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signatures.
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Not checking this could lead to an integer overflow. The value is assigned
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to the `len` field of a chunk (`size_t`), which is further used in
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calculations to check the padding structure and (if that is passed by a
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matching crafted signature value) eventually a memcpy() that will result
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in a segmentation fault.
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Fixes: a22316520b91 ("signature-params: Add functions to parse/build ASN.1 RSASSA-PSS params")
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Fixes: 7d6b81648b2d ("gmp: Add support for RSASSA-PSS signature verification")
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Fixes: CVE-2021-41990
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---
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src/libstrongswan/credentials/keys/signature_params.c | 6 +++++-
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src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c | 2 +-
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2 files changed, 6 insertions(+), 2 deletions(-)
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diff --git a/src/libstrongswan/credentials/keys/signature_params.c b/src/libstrongswan/credentials/keys/signature_params.c
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index d89bd2c96bb5..837de8443d43 100644
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--- a/src/libstrongswan/credentials/keys/signature_params.c
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+++ b/src/libstrongswan/credentials/keys/signature_params.c
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@@ -322,7 +322,11 @@ bool rsa_pss_params_parse(chunk_t asn1, int level0, rsa_pss_params_t *params)
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case RSASSA_PSS_PARAMS_SALT_LEN:
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if (object.len)
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{
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- params->salt_len = (size_t)asn1_parse_integer_uint64(object);
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+ params->salt_len = (ssize_t)asn1_parse_integer_uint64(object);
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+ if (params->salt_len < 0)
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+ {
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+ goto end;
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+ }
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}
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break;
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case RSASSA_PSS_PARAMS_TRAILER:
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diff --git a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
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index f9bd1d314dec..3a775090883e 100644
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--- a/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
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+++ b/src/libstrongswan/plugins/gmp/gmp_rsa_public_key.c
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@@ -168,7 +168,7 @@ static bool verify_emsa_pss_signature(private_gmp_rsa_public_key_t *this,
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int i;
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bool success = FALSE;
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- if (!params)
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+ if (!params || params->salt_len < 0)
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{
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return FALSE;
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}
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--
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2.25.1
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