shadow-utils/shadow-4.8.1-salt_c_comments.patch

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From dbf230e4cf823dd6b6a3bad6d29dfad4f0ffa8fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Esser?= <besser82@fedoraproject.org>
Date: Mon, 14 Jun 2021 23:28:28 +0200
Subject: [PATCH] libmisc/salt.c: Add comments how the minmum buffer length is
computed.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In the previous commit we refactored the functions converting the
rounds number into a string for use with the crypt() function, to
not require any static buffer anymore.
Add some clarifying comments about how the minimum required buffer
length is computed inside of these functions.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
---
libmisc/salt.c | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/libmisc/salt.c b/libmisc/salt.c
index 98982ed1..e17093fc 100644
--- a/libmisc/salt.c
+++ b/libmisc/salt.c
@@ -216,7 +216,14 @@ static /*@observer@*/void SHA_salt_rounds_to_buf (char *buf, /*@null@*/int *pref
return;
}
- /* Check if the result buffer is long enough. */
+ /*
+ * Check if the result buffer is long enough.
+ * We are going to write a maximum of 17 bytes,
+ * plus one byte for the terminator.
+ * rounds=XXXXXXXXX$
+ * 00000000011111111
+ * 12345678901234567
+ */
assert (GENSALT_SETTING_SIZE > buf_begin + 17);
(void) snprintf (buf + buf_begin, 18, "rounds=%lu$", rounds);
@@ -274,7 +281,14 @@ static /*@observer@*/void BCRYPT_salt_rounds_to_buf (char *buf, /*@null@*/int *p
rounds = 19;
}
- /* Check if the result buffer is long enough. */
+ /*
+ * Check if the result buffer is long enough.
+ * We are going to write three bytes,
+ * plus one byte for the terminator.
+ * XX$
+ * 000
+ * 123
+ */
assert (GENSALT_SETTING_SIZE > buf_begin + 3);
(void) snprintf (buf + buf_begin, 4, "%2.2lu$", rounds);
@@ -308,8 +322,15 @@ static /*@observer@*/void YESCRYPT_salt_cost_to_buf (char *buf, /*@null@*/int *p
cost = Y_COST_MAX;
}
- /* Check if the result buffer is long enough. */
- assert (GENSALT_SETTING_SIZE > buf_begin + 3);
+ /*
+ * Check if the result buffer is long enough.
+ * We are going to write four bytes,
+ * plus one byte for the terminator.
+ * jXX$
+ * 0000
+ * 1234
+ */
+ assert (GENSALT_SETTING_SIZE > buf_begin + 4);
buf[buf_begin + 0] = 'j';
if (cost < 3) {