[PATCH] gpg-interface: trim only CR characters that precede LF

[Okhuomon Ajayi <okhuomonajayi54@gmail.com>]

The current implementation of remove_cr_after() drops every carriage
return (CR) it finds, even when the CR is not part of a CRLF sequence.
This can damage data that legitimately contains standalone CR bytes,
such as binary payloads or text formatted for older systems.

Update remove_cr_after() to remove a CR only when it is immediately
followed by an LF. This keeps Windows-style CRLF normalization intact
while preserving lone CR characters that are part of the data itself.

Signed-off-by: Okhuomon Ajayi <okhuomonajayi54@gmail.com>
---
 gpg-interface.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/gpg-interface.c b/gpg-interface.c
index 2f4f0e32cb..c961607444 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -965,19 +965,22 @@ int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *sig
 }
 
 /*
- * Strip CR from the line endings, in case we are on Windows.
- * NEEDSWORK: make it trim only CRs before LFs and rename
+ * Trim CR characters only when they appear before LF (\r\n) line endings.
+ * This avoids removing legitimate lone CRs from teh content.
  */
-static void remove_cr_after(struct strbuf *buffer, size_t offset)
+static void trim_cr_before_lf(struct strbuf *buffer, size_t offset)
 {
 	size_t i, j;
 
 	for (i = j = offset; i < buffer->len; i++) {
-		if (buffer->buf[i] != '\r') {
+	     /* skip CR only if it comes right before LF */
+		if (buffer->buf[i] == '\r' && i + 1 < buffer->len && buffer->buf[i+1] == '\n')
+		    continue;
+ 
 			if (i != j)
 				buffer->buf[j] = buffer->buf[i];
 			j++;
-		}
+		
 	}
 	strbuf_setlen(buffer, j);
 }
@@ -1023,8 +1026,10 @@ static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature,
 	}
 	strbuf_release(&gpg_status);
 
-	/* Strip CR from the line endings, in case we are on Windows. */
-	remove_cr_after(signature, bottom);
+	/* Trim carriage returns (CR) only when they appear before line feeds (LF),.
+	*  mainly for handling Windows-style line endings
+ 	*/
+	trim_cr_before_lf(signature, bottom);
 
 	return 0;
 }
@@ -1110,8 +1115,10 @@ static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
 			ssh_signature_filename.buf);
 		goto out;
 	}
-	/* Strip CR from the line endings, in case we are on Windows. */
-	remove_cr_after(signature, bottom);
+	/* Trim carriage returns (CR) only when they appear before line feeds (LF),
+	*  mainly for handling Windows-style line endings.
+	*/
+	trim_cr_before_lf(signature, bottom);
 
 out:
 	if (key_file)
-- 
2.43.0