42 lines
1.3 KiB
Diff
42 lines
1.3 KiB
Diff
From a2ed82d40964bbc0d64cd717aa0a5a892117d2e6 Mon Sep 17 00:00:00 2001
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From: Viktor Szakats <commit@vsz.me>
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Date: Thu, 23 Jul 2026 10:32:04 +0200
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Subject: [PATCH] openssl: fix potential OOB read/write with AES-GCM in
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`ssh2_cipher_crypt()`
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By applying two bounds checks to non-debug builds.
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Reported-by: Vladimir Eli Tokarev
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Fixes GHSA-c4f7-cvfc-33j7
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Follow-up to 3c953c05d67eb1ebcfd3316f279f12c4b1d600b4 #797
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Closes #2401
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---
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src/openssl.c | 10 ++++++----
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1 file changed, 6 insertions(+), 4 deletions(-)
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diff --git a/src/openssl.c b/src/openssl.c
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index 6a38b55b91..31ef6db371 100644
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--- a/src/openssl.c
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+++ b/src/openssl.c
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@@ -945,13 +945,15 @@ int ssh2_cipher_crypt(ssh2_cipher_ctx *ctx, SSH2_CIPHER_T(algo), int encrypt,
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const int aadlen = (is_aesgcm && IS_FIRST(firstlast)) ? 4 : 0;
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/* size of AT, if present */
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const int authenticationtag = IS_LAST(firstlast) ? authlen : 0;
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- /* length to encrypt */
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- const int cryptlen = (unsigned int)blocksize - aadlen - authenticationtag;
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+ unsigned int cryptlen; /* length to encrypt */
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(void)algo;
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- assert(blocksize <= sizeof(buf));
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- assert(cryptlen >= 0);
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+ if(blocksize > sizeof(buf) ||
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+ blocksize < (size_t)(aadlen + authenticationtag))
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+ return 1;
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+
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+ cryptlen = (unsigned int)blocksize - aadlen - authenticationtag;
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#if LIBSSH2_AES_GCM
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/* First block */
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