Date: Fri, 22 May 2026 17:58:12 +0000 From: Dag-Erling=?utf-8?Q? Sm=C3=B8rg?=rav <des@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 933893771344 - main - tftpd: Add missing bounds checks Message-ID: <6a109934.39235.25ca255c@gitrepo.freebsd.org>
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The branch main has been updated by des: URL: https://cgit.FreeBSD.org/src/commit/?id=933893771344e1647eeda152016b938fdc30ccdc commit 933893771344e1647eeda152016b938fdc30ccdc Author: Dag-Erling Smørgrav <des@FreeBSD.org> AuthorDate: 2026-05-22 17:57:31 +0000 Commit: Dag-Erling Smørgrav <des@FreeBSD.org> CommitDate: 2026-05-22 17:57:31 +0000 tftpd: Add missing bounds checks In send_[rw]rq(), we were using strlcpy() to avoid overflowing our packet buffer, then failing to check the result and blithely advancing our pointer by the full length. Luckily, this code is only ever used by tftp(1), not tftpd(8). MFC after: 1 week Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D57075 --- libexec/tftpd/tftp-io.c | 62 +++++++++++++++++++++++++++---------------------- 1 file changed, 34 insertions(+), 28 deletions(-) diff --git a/libexec/tftpd/tftp-io.c b/libexec/tftpd/tftp-io.c index 50102e652d2f..3384071d6df2 100644 --- a/libexec/tftpd/tftp-io.c +++ b/libexec/tftpd/tftp-io.c @@ -173,11 +173,11 @@ send_error(int peer, int error) int send_wrq(int peer, char *filename, char *mode) { - int n; + char buf[MAXPKTSIZE]; struct tftphdr *tp; char *bp; - char buf[MAXPKTSIZE]; - int size; + size_t len; + int n, size; if (debug & DEBUG_PACKETS) tftp_log(LOG_DEBUG, "Sending WRQ: filename: '%s', mode '%s'", @@ -191,17 +191,17 @@ send_wrq(int peer, char *filename, char *mode) size = offsetof(struct tftphdr, th_stuff); bp = tp->th_stuff; - strlcpy(bp, filename, sizeof(buf) - size); - bp += strlen(filename); - *bp = 0; - bp++; - size += strlen(filename) + 1; - - strlcpy(bp, mode, sizeof(buf) - size); - bp += strlen(mode); - *bp = 0; - bp++; - size += strlen(mode) + 1; + len = strlcpy(bp, filename, sizeof(buf) - size); + if (len >= sizeof(buf) - size) + goto overflow; + bp += len + 1; + size += len + 1; + + len = strlcpy(bp, mode, sizeof(buf) - size); + if (len >= sizeof(buf) - size) + goto overflow; + bp += len + 1; + size += len + 1; if (options_rfc_enabled) size += make_options(peer, bp, sizeof(buf) - size); @@ -213,6 +213,9 @@ send_wrq(int peer, char *filename, char *mode) return (1); } return (0); +overflow: + tftp_log(LOG_ERR, "%s: file name too long", __func__); + return (1); } /* @@ -221,11 +224,11 @@ send_wrq(int peer, char *filename, char *mode) int send_rrq(int peer, char *filename, char *mode) { - int n; + char buf[MAXPKTSIZE]; struct tftphdr *tp; char *bp; - char buf[MAXPKTSIZE]; - int size; + size_t len; + int n, size; if (debug & DEBUG_PACKETS) tftp_log(LOG_DEBUG, "Sending RRQ: filename: '%s', mode '%s'", @@ -239,17 +242,17 @@ send_rrq(int peer, char *filename, char *mode) size = offsetof(struct tftphdr, th_stuff); bp = tp->th_stuff; - strlcpy(bp, filename, sizeof(buf) - size); - bp += strlen(filename); - *bp = 0; - bp++; - size += strlen(filename) + 1; - - strlcpy(bp, mode, sizeof(buf) - size); - bp += strlen(mode); - *bp = 0; - bp++; - size += strlen(mode) + 1; + len = strlcpy(bp, filename, sizeof(buf) - size); + if (len >= sizeof(buf) - size) + goto overflow; + bp += len + 1; + size += len + 1; + + len = strlcpy(bp, mode, sizeof(buf) - size); + if (len >= sizeof(buf) - size) + goto overflow; + bp += len + 1; + size += len + 1; if (options_rfc_enabled) { options_set_request(OPT_TSIZE, "0"); @@ -263,6 +266,9 @@ send_rrq(int peer, char *filename, char *mode) return (1); } return (0); +overflow: + tftp_log(LOG_ERR, "%s: file name too long", __func__); + return (1); } /*home | help
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