[1/4] mailinfo: treat header values as C strings
diff mbox series

Message ID 20200211171852.GA2119034@coredump.intra.peff.net
State New
Headers show
Series
  • some more mailinfo cleanups
Related show

Commit Message

Jeff King Feb. 11, 2020, 5:18 p.m. UTC
We read each header line into a strbuf, which means that we could
in theory handle header values with embedded NUL bytes. But in practice,
the values we parse out are passed to decode_header(), which uses
strstr(), strchr(), etc. And we would not expect such bytes anyway; they
are forbidden by RFC822, etc and any non-ASCII characters should be
encoded with RFC2047 encoding.

So let's switch to using strbuf_addstr(), which saves us some length
computations (and will enable further cleanups in this code).

Signed-off-by: Jeff King <peff@peff.net>
---
We _could_ skip this and compute the length later as:

  line->len - (val - line->buf)

but I like the simplification.

 mailinfo.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Eric Sunshine Feb. 11, 2020, 5:26 p.m. UTC | #1
On Tue, Feb 11, 2020 at 12:18 PM Jeff King <peff@peff.net> wrote:
> We read each header line into a strbuf, which means that we could
> in theory handle header values with embedded NUL bytes. But in practice,
> the values we parse out are passed to decode_header(), which uses
> strstr(), strchr(), etc. And we would not expect such bytes anyway; they
> are forbidden by RFC822, etc and any non-ASCII characters should be

s/etc/etc./

> encoded with RFC2047 encoding.
>
> So let's switch to using strbuf_addstr(), which saves us some length
> computations (and will enable further cleanups in this code).
>
> Signed-off-by: Jeff King <peff@peff.net>

Patch
diff mbox series

diff --git a/mailinfo.c b/mailinfo.c
index 402ef04dd1..59d5a8b8f3 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -557,7 +557,7 @@  static int check_header(struct mailinfo *mi,
 			/* Unwrap inline B and Q encoding, and optionally
 			 * normalize the meta information to utf8.
 			 */
-			strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
+			strbuf_addstr(&sb, line->buf + len + 2);
 			decode_header(mi, &sb);
 			handle_header(&hdr_data[i], &sb);
 			ret = 1;
@@ -568,23 +568,23 @@  static int check_header(struct mailinfo *mi,
 	/* Content stuff */
 	if (cmp_header(line, "Content-Type")) {
 		len = strlen("Content-Type: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
+		strbuf_addstr(&sb, line->buf + len);
 		decode_header(mi, &sb);
 		handle_content_type(mi, &sb);
 		ret = 1;
 		goto check_header_out;
 	}
 	if (cmp_header(line, "Content-Transfer-Encoding")) {
 		len = strlen("Content-Transfer-Encoding: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
+		strbuf_addstr(&sb, line->buf + len);
 		decode_header(mi, &sb);
 		handle_content_transfer_encoding(mi, &sb);
 		ret = 1;
 		goto check_header_out;
 	}
 	if (cmp_header(line, "Message-Id")) {
 		len = strlen("Message-Id: ");
-		strbuf_add(&sb, line->buf + len, line->len - len);
+		strbuf_addstr(&sb, line->buf + len);
 		decode_header(mi, &sb);
 		if (mi->add_message_id)
 			mi->message_id = strbuf_detach(&sb, NULL);