threads / patch / 64497

patchwincred: avoid memory corruption

Subject: [PATCH] wincred: avoid memory corruption

## tl;dr

One message between Nov 17, 2025 and Nov 17, 2025. Diffs are folded; open one to read it.

replies: 0people: 1as markdown or json

Johannes Schindelin via GitGitGadget· Nov 17, 2025, 20:39 UTC · lore
From: David Macek <david.macek.0@gmail.com>

`wcsncpy_s()` wants to write the terminating null character so we need to allocate one more space for it in the target memory block.

This should fix crashes when trying to read passwords. When this happened, the password/token wouldn't print out and Git would therefore ask for a new password every time.

Signed-off-by: David Macek <david.macek.0@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
    wincred: Avoid memory corruption
    
    This patch wants to be upstreamed...
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2005%2Fdscho%2Fwincred-Avoid-memory-corruption-5856--v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2005/dscho/wincred-Avoid-memory-corruption-5856--v1
Pull-Request: https://github.com/gitgitgadget/git/pull/2005
 contrib/credential/wincred/git-credential-wincred.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to contrib/credential/wincred/git-credential-wincred.c +1 −1
diff --git a/contrib/credential/wincred/git-credential-wincred.c b/contrib/credential/wincred/git-credential-wincred.c
index 5683846b4b..73c2b9b72a 100644
--- a/contrib/credential/wincred/git-credential-wincred.c
+++ b/contrib/credential/wincred/git-credential-wincred.c
@@ -165,7 +165,7 @@ static void get_credential(void)
 			write_item("username", creds[i]->UserName,
 				creds[i]->UserName ? wcslen(creds[i]->UserName) : 0);
 			if (creds[i]->CredentialBlobSize > 0) {
-				secret = xmalloc(creds[i]->CredentialBlobSize);
+				secret = xmalloc(creds[i]->CredentialBlobSize + sizeof(WCHAR));
 				wcsncpy_s(secret, creds[i]->CredentialBlobSize, (LPCWSTR)creds[i]->CredentialBlob, creds[i]->CredentialBlobSize / sizeof(WCHAR));
 				line = wcstok_s(secret, L"\r\n", &remaining_lines);
 				write_item("password", line, line ? wcslen(line) : 0);

base-commit: 9a2fb147f2c61d0cab52c883e7e26f5b7948e3ed
-- 
gitgitgadget

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