From 4d87db0f11bcdd5c54fadb92351b603bd07f76f8 Mon Sep 17 00:00:00 2001
From: Alexander Bokovoy <abokovoy@redhat.com>
Date: Mon, 30 Jan 2023 11:44:49 +0200
Subject: [PATCH] Pass right remaining buffer size in hsm_hex_unparse to handle
 string fortification

When string fortification is in use (-DFORTIFY_SOURCE=3), GCC and glibc
will cut few bytes off the string buffer for prevention of buffer
overruns. As a result, hsm_hex_unparse() will call into snprintf() with
a buffer length bigger than the size of the buffer as seen by the
GCC/glibc pair.

See also: https://pagure.io/freeipa/issue/9312

Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
---
 libhsm/src/lib/libhsm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libhsm/src/lib/libhsm.c b/libhsm/src/lib/libhsm.c
index 88dc79e31..8f1e0c3bc 100644
--- a/libhsm/src/lib/libhsm.c
+++ b/libhsm/src/lib/libhsm.c
@@ -1382,7 +1382,7 @@ hsm_hex_unparse(char *dst, const unsigned char *src, size_t len)
     size_t i;
 
     for (i = 0; i < len; i++) {
-        snprintf(dst + (2*i), dst_len, "%02x", src[i]);
+        snprintf(dst + (2*i), dst_len - (2*i), "%02x", src[i]);
     }
     dst[len*2] = '\0';
 }
-- 
2.39.0