git: fab38dac6506 - releng/11.4 - Fix libfetch out of bounds read.

[Gordon Tetlow]

The branch releng/11.4 has been updated by gordon:

URL: https://cgit.FreeBSD.org/src/commit/?id=fab38dac650664eb614ab28ff2535d97bec21e89

commit fab38dac650664eb614ab28ff2535d97bec21e89
Author:     Gordon Tetlow <gordon at FreeBSD.org>
AuthorDate: 2021-08-24 18:02:42 +0000
Commit:     Gordon Tetlow <gordon at FreeBSD.org>
CommitDate: 2021-08-24 18:02:42 +0000

    Fix libfetch out of bounds read.
    
    Approved by:    so
    Security:       SA-21:15.libfetch
    Security:       CVE-2021-36159
---
 lib/libfetch/ftp.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/libfetch/ftp.c b/lib/libfetch/ftp.c
index c034b5efa240..1755012fc99b 100644
--- a/lib/libfetch/ftp.c
+++ b/lib/libfetch/ftp.c
@@ -702,8 +702,11 @@ ftp_transfer(conn_t *conn, const char *oper, const char *file,
 				goto ouch;
 			}
 			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
-			for (i = 0; *p && i < l; i++, p++)
+			for (i = 0; *p && i < l; i++, p++) {
 				addr[i] = strtol(p, &p, 10);
+				if (*p == '\0' && i < l - 1)
+					break;
+			}
 			if (i < l) {
 				e = FTP_PROTOCOL_ERROR;
 				goto ouch;