66 lines
1.6 KiB
Diff
66 lines
1.6 KiB
Diff
From 91fcfb5708f829ecff7d098ed4c0fc8f2da6d599 Mon Sep 17 00:00:00 2001
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From: Jan Friesse <jfriesse@redhat.com>
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Date: Wed, 21 Feb 2024 18:12:28 +0100
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Subject: [PATCH 2/4] auth: Check result of gcrypt gcry_md_get_algo_dlen
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When unknown hash is passed to gcry_md_get_algo_dlen 0 is returned. This
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value is then used for memcmp so wrong hmac might be accepted as
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correct.
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Signed-off-by: Jan Friesse <jfriesse@redhat.com>
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---
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src/auth.c | 16 +++++++++++++---
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1 file changed, 13 insertions(+), 3 deletions(-)
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diff --git a/src/auth.c b/src/auth.c
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index 8f86b9a..a3b3d20 100644
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--- a/src/auth.c
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+++ b/src/auth.c
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@@ -28,6 +28,11 @@ int calc_hmac(const void *data, size_t datalen,
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{
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static gcry_md_hd_t digest;
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gcry_error_t err;
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+ int hlen;
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+
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+ hlen = gcry_md_get_algo_dlen(hid);
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+ if (!hlen)
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+ return -1;
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if (!digest) {
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err = gcry_md_open(&digest, hid, GCRY_MD_FLAG_HMAC);
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@@ -42,7 +47,7 @@ int calc_hmac(const void *data, size_t datalen,
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}
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}
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gcry_md_write(digest, data, datalen);
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- memcpy(result, gcry_md_read(digest, 0), gcry_md_get_algo_dlen(hid));
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+ memcpy(result, gcry_md_read(digest, 0), hlen);
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gcry_md_reset(digest);
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return 0;
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}
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@@ -54,15 +59,20 @@ int verify_hmac(const void *data, size_t datalen,
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{
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unsigned char *our_hmac;
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int rc;
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+ int hlen;
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+
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+ hlen = gcry_md_get_algo_dlen(hid);
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+ if (!hlen)
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+ return -1;
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- our_hmac = malloc(gcry_md_get_algo_dlen(hid));
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+ our_hmac = malloc(hlen);
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if (!our_hmac)
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return -1;
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rc = calc_hmac(data, datalen, hid, our_hmac, key, keylen);
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if (rc)
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goto out_free;
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- rc = memcmp(our_hmac, hmac, gcry_md_get_algo_dlen(hid));
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+ rc = memcmp(our_hmac, hmac, hlen);
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out_free:
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if (our_hmac)
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--
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2.44.0
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