dovecot-2.2: imap: harden read_uoff_t() against overflow

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/9b9b6dc7dd9b
changeset: 17557:9b9b6dc7dd9b
user:      Phil Carmody <phil at dovecot.fi>
date:      Wed Jul 02 18:21:24 2014 +0300
description:
imap: harden read_uoff_t() against overflow
Invalid strings like "20496382304121724029" (2^64*10/9) can be parsed
as valid. Use the new helper.

Change in error behaviour - previously overflows, if they were detected,
caused *p to point to the digit causing the overflow. Now it's undefined.
Current clients don't care about this difference, they just bail.

Signed-off-by: Phil Carmody <phil at dovecot.fi>

diffstat:

 src/imap/imap-fetch-body.c |  14 +-------------
 1 files changed, 1 insertions(+), 13 deletions(-)

diffs (24 lines):

diff -r dfc55d17314a -r 9b9b6dc7dd9b src/imap/imap-fetch-body.c
--- a/src/imap/imap-fetch-body.c	Wed Jul 02 18:21:24 2014 +0300
+++ b/src/imap/imap-fetch-body.c	Wed Jul 02 18:21:24 2014 +0300
@@ -208,19 +208,7 @@
    becomes too big and wraps. */
 static int read_uoff_t(const char **p, uoff_t *value)
 {
-	uoff_t prev;
-
-	*value = 0;
-	while (**p >= '0' && **p <= '9') {
-		prev = *value;
-		*value = *value * 10 + (**p - '0');
-
-		if (*value < prev)
-			return -1;
-
-		(*p)++;
-	}
-	return 0;
+	return str_parse_uoff(*p, value, p);
 }
 
 static int