File openssl-CVE-2021-23840.patch of Package compat-openssl098.29129
From 6a51b9e1d0cf0bf8515f7201b68fb0a3482b3dc1 Mon Sep 17 00:00:00 2001
From: Matt Caswell <matt@openssl.org>
Date: Tue, 2 Feb 2021 17:17:23 +0000
Subject: [PATCH] Don't overflow the output length in EVP_CipherUpdate calls
CVE-2021-23840
Reviewed-by: Paul Dale <pauli@openssl.org>
---
crypto/err/openssl.txt | 3 ++-
crypto/evp/evp_enc.c | 27 +++++++++++++++++++++++++++
crypto/evp/evp_err.c | 4 +++-
include/openssl/evperr.h | 7 +++----
4 files changed, 35 insertions(+), 6 deletions(-)
Index: openssl-0.9.8j/crypto/evp/evp_enc.c
===================================================================
--- openssl-0.9.8j.orig/crypto/evp/evp_enc.c
+++ openssl-0.9.8j/crypto/evp/evp_enc.c
@@ -57,6 +57,7 @@
*/
#include <stdio.h>
+#include <limits.h>
#include "cryptlib.h"
#include <openssl/evp.h>
#include <openssl/err.h>
@@ -177,6 +178,18 @@ int EVP_EncryptUpdate(EVP_CIPHER_CTX *ct
else
{
j=bl-i;
+ /*
+ * Once we've processed the first j bytes from in, the amount of
+ * data left that is a multiple of the block length is:
+ * (inl - j) & ~(bl - 1)
+ * We must ensure that this amount of data, plus the one block that
+ * we process from ctx->buf does not exceed INT_MAX
+ */
+ if (((inl - j) & ~(bl - 1)) > INT_MAX - bl) {
+ EVPerr(EVP_F_EVP_ENCRYPTUPDATE,
+ EVP_R_OUTPUT_WOULD_OVERFLOW);
+ return 0;
+ }
memcpy(&(ctx->buf[i]),in,j);
if(!M_do_cipher(ctx,out,ctx->buf,bl)) return 0;
inl-=j;
@@ -264,6 +277,19 @@ int EVP_DecryptUpdate(EVP_CIPHER_CTX *ct
if(ctx->final_used)
{
+ /*
+ * final_used is only ever set if buf_len is 0. Therefore the maximum
+ * length output we will ever see from evp_EncryptUpdate is
+ * the maximum multiple of the block length that is <= inl, or just:
+ * inl & ~(b - 1)
+ * Since final_used has been set then the final output length is:
+ * (inl & ~(b - 1)) + b
+ * This must never exceed INT_MAX
+ */
+ if ((inl & ~(b - 1)) > INT_MAX - b) {
+ EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_OUTPUT_WOULD_OVERFLOW);
+ return 0;
+ }
memcpy(out,ctx->final,b);
out+=b;
fix_len = 1;
Index: openssl-0.9.8j/crypto/evp/evp_err.c
===================================================================
--- openssl-0.9.8j.orig/crypto/evp/evp_err.c
+++ openssl-0.9.8j/crypto/evp/evp_err.c
@@ -87,9 +87,11 @@ static ERR_STRING_DATA EVP_str_functs[]=
{ERR_FUNC(EVP_F_EVP_CIPHER_CTX_CTRL), "EVP_CIPHER_CTX_ctrl"},
{ERR_FUNC(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH), "EVP_CIPHER_CTX_set_key_length"},
{ERR_FUNC(EVP_F_EVP_DECRYPTFINAL_EX), "EVP_DecryptFinal_ex"},
+{ERR_FUNC(EVP_F_EVP_DECRYPTUPDATE), "EVP_DecryptUpdate"},
{ERR_FUNC(EVP_F_EVP_DIGESTINIT), "EVP_DigestInit"},
{ERR_FUNC(EVP_F_EVP_DIGESTINIT_EX), "EVP_DigestInit_ex"},
{ERR_FUNC(EVP_F_EVP_ENCRYPTFINAL_EX), "EVP_EncryptFinal_ex"},
+{ERR_FUNC(EVP_F_EVP_ENCRYPTUPDATE), "EVP_EncryptUpdate"},
{ERR_FUNC(EVP_F_EVP_MD_CTX_COPY_EX), "EVP_MD_CTX_copy_ex"},
{ERR_FUNC(EVP_F_EVP_OPENINIT), "EVP_OpenInit"},
{ERR_FUNC(EVP_F_EVP_PBE_ALG_ADD), "EVP_PBE_alg_add"},
@@ -155,6 +157,7 @@ static ERR_STRING_DATA EVP_str_reasons[]
{ERR_REASON(EVP_R_NO_DSA_PARAMETERS) ,"no dsa parameters"},
{ERR_REASON(EVP_R_NO_SIGN_FUNCTION_CONFIGURED),"no sign function configured"},
{ERR_REASON(EVP_R_NO_VERIFY_FUNCTION_CONFIGURED),"no verify function configured"},
+{ERR_REASON(EVP_R_OUTPUT_WOULD_OVERFLOW), "output would overflow"},
{ERR_REASON(EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE),"pkcs8 unknown broken type"},
{ERR_REASON(EVP_R_PUBLIC_KEY_NOT_RSA) ,"public key not rsa"},
{ERR_REASON(EVP_R_SEED_KEY_SETUP_FAILED) ,"seed key setup failed"},
Index: openssl-0.9.8j/crypto/evp/evp.h
===================================================================
--- openssl-0.9.8j.orig/crypto/evp/evp.h
+++ openssl-0.9.8j/crypto/evp/evp.h
@@ -972,9 +972,11 @@ void ERR_load_EVP_strings(void);
#define EVP_F_EVP_CIPHER_CTX_CTRL 124
#define EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH 122
#define EVP_F_EVP_DECRYPTFINAL_EX 101
+#define EVP_F_EVP_DECRYPTUPDATE 180
#define EVP_F_EVP_DIGESTINIT 136
#define EVP_F_EVP_DIGESTINIT_EX 128
#define EVP_F_EVP_ENCRYPTFINAL_EX 127
+#define EVP_F_EVP_ENCRYPTUPDATE 181
#define EVP_F_EVP_MD_CTX_COPY_EX 110
#define EVP_F_EVP_OPENINIT 102
#define EVP_F_EVP_PBE_ALG_ADD 115
@@ -1037,6 +1039,7 @@ void ERR_load_EVP_strings(void);
#define EVP_R_NO_DSA_PARAMETERS 116
#define EVP_R_NO_SIGN_FUNCTION_CONFIGURED 104
#define EVP_R_NO_VERIFY_FUNCTION_CONFIGURED 105
+#define EVP_R_OUTPUT_WOULD_OVERFLOW 184
#define EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE 117
#define EVP_R_PUBLIC_KEY_NOT_RSA 106
#define EVP_R_UNKNOWN_OPTION 149
