[src/trunk]: src/usr.bin/mail PR/47657: Steffen "Daode" Nurpmeso: quoted prin...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f6733ea83ab0
branches:  trunk
changeset: 784943:f6733ea83ab0
user:      christos <christos%NetBSD.org@localhost>
date:      Thu Feb 14 18:23:45 2013 +0000

description:
PR/47657: Steffen "Daode" Nurpmeso: quoted printable CTE exceeds RFC limit.
- Encapsulated all the content-transfer-encoding stuff in mime_codecs.c
- Replaced calls of strtol(3) with a handcrafted version that allows simple
  error checking by testing the return value. This allows to easily add
  special code to handle illegal QP sequences.

diffstat:

 usr.bin/mail/mime_codecs.c |  118 ++++++++++++++++++++++++++++++++++++++++----
 usr.bin/mail/mime_codecs.h |    4 +-
 usr.bin/mail/mime_header.c |   74 +---------------------------
 3 files changed, 111 insertions(+), 85 deletions(-)

diffs (282 lines):

diff -r 5e7932c80ec9 -r f6733ea83ab0 usr.bin/mail/mime_codecs.c
--- a/usr.bin/mail/mime_codecs.c        Thu Feb 14 17:12:23 2013 +0000
+++ b/usr.bin/mail/mime_codecs.c        Thu Feb 14 18:23:45 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mime_codecs.c,v 1.10 2012/11/24 21:40:02 christos Exp $        */
+/*     $NetBSD: mime_codecs.c,v 1.11 2013/02/14 18:23:45 christos Exp $        */
 
 /*-
  * Copyright (c) 2006 The NetBSD Foundation, Inc.
@@ -52,7 +52,7 @@
 
 #include <sys/cdefs.h>
 #ifndef __lint__
-__RCSID("$NetBSD: mime_codecs.c,v 1.10 2012/11/24 21:40:02 christos Exp $");
+__RCSID("$NetBSD: mime_codecs.c,v 1.11 2013/02/14 18:23:45 christos Exp $");
 #endif /* not __lint__ */
 
 #include <assert.h>
@@ -389,9 +389,83 @@
 /************************************************************************
  * Core quoted-printable routines.
  *
- * Note: the header QP routines are slightly different and burried
- * inside mime_header.c
+ * Defined in sec 6.7 of RFC 2045.
+ */
+
+/*
+ * strtol(3), but inline and with easy error indication.
  */
+static inline int
+_qp_cfromhex(char const *hex)
+{
+       /* Be robust, allow lowercase hexadecimal letters, too */
+       static unsigned char const atoi16[] = {
+               0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, /* 0x30-0x37 */
+               0x08, 0x09, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 0x38-0x3F */
+               0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0xFF, /* 0x40-0x47 */
+               0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 0x48-0x4f */
+               0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 0x50-0x57 */
+               0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 0x58-0x5f */
+               0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0xFF  /* 0x60-0x67 */
+       };
+       unsigned char i1, i2;
+       int r;
+
+       if ((i1 = (unsigned char)hex[0] - '0') >= __arraycount(atoi16) ||
+           (i2 = (unsigned char)hex[1] - '0') >= __arraycount(atoi16))
+               goto jerr;
+       i1 = atoi16[i1];
+       i2 = atoi16[i2];
+       if ((i1 | i2) & 0xF0)
+               goto jerr;
+       r = i1;
+       r <<= 4;
+       r += i2;
+jleave:
+       return r;
+jerr:
+       r = -1;
+       goto jleave;
+}
+
+/*
+ * Header specific "quoted-printable" decode!
+ * Differences with body QP decoding (see rfc 2047, sec 4.2):
+ * 1) '=' occurs _only_ when followed by two hex digits (FWS is not allowed).
+ * 2) Spaces can be encoded as '_' in headers for readability.
+ */
+static ssize_t
+mime_QPh_decode(char *outbuf, size_t outlen, const char *inbuf, size_t inlen)
+{
+       const char *p, *inend;
+       char *outend;
+       char *q;
+
+       outend = outbuf + outlen;
+       inend = inbuf + inlen;
+       q = outbuf;
+       for (p = inbuf; p < inend; p++) {
+               if (q >= outend)
+                       return -1;
+               if (*p == '=') {
+                       p++;
+                       if (p + 1 < inend) {
+                               int c = _qp_cfromhex(p++);
+                               if (c < 0)
+                                       return -1;
+                               *q++ = (char)c;
+                       }
+                       else
+                               return -1;
+               }
+               else if (*p == '_')  /* header's may encode ' ' as '_' */
+                       *q++ = ' ';
+               else
+                       *q++ = *p;
+       }
+       return q - outbuf;
+}
+
 
 static int
 mustquote(unsigned char *p, unsigned char *end, size_t l)
@@ -479,8 +553,11 @@
                }
                else {
                        if (*p == '\n') {
-                               if (p > beg && p[-1] == '\r')
+                               if (p > beg && p[-1] == '\r') {
+                                       if (l + 4 > limit)
+                                               (void)fputs("=\n", fo);
                                        (void)fputs("=0A=", fo);
+                               }
                                l = (size_t)-1;
                        }
                        else if (l + 2 > limit) {
@@ -541,14 +618,11 @@
                                while (p < end && is_WSP(*p))
                                        p++;
                                if (*p != '\n' && p + 1 < end) {
-                                       int c;
-                                       char buf[3];
-
-                                       buf[0] = *p++;
-                                       buf[1] = *p;
-                                       buf[2] = '\0';
-                                       c = (int)strtol(buf, NULL, 16);
-                                       (void)fputc(c, fo);
+                                       int c = _qp_cfromhex(p++);
+                                       if (c >= 0)
+                                               (void)fputc(c, fo);
+                                       else
+                                               (void)fputs("[?]", fo);
                                }
                        }
                        else
@@ -631,6 +705,24 @@
 }
 
 /*
+ * Decode a RFC 2047 extended message header *encoded-word*.
+ * *encoding* is the corresponding character of the *encoded-word*.
+ */
+PUBLIC ssize_t
+mime_rfc2047_decode(char encoding, char *outbuf, size_t outlen,
+       const char *inbuf, size_t inlen)
+{
+       ssize_t declen = -1;
+
+       if (encoding == 'B' || encoding == 'b') {
+               if (outlen >= 3 * roundup(inlen, 4) / 4)
+                       declen = mime_b64tobin(outbuf, inbuf, inlen);
+       } else if (encoding == 'Q' || encoding == 'q')
+               declen = mime_QPh_decode(outbuf, outlen, inbuf, inlen);
+       return declen;
+}
+
+/*
  * This is for use in complete.c and mime.c to get the list of
  * encoding names without exposing the transfer_encoding_tbl[].  The
  * first name is returned if called with a pointer to a NULL pointer.
diff -r 5e7932c80ec9 -r f6733ea83ab0 usr.bin/mail/mime_codecs.h
--- a/usr.bin/mail/mime_codecs.h        Thu Feb 14 17:12:23 2013 +0000
+++ b/usr.bin/mail/mime_codecs.h        Thu Feb 14 18:23:45 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mime_codecs.h,v 1.4 2008/04/28 20:24:14 martin Exp $   */
+/*     $NetBSD: mime_codecs.h,v 1.5 2013/02/14 18:23:45 christos Exp $ */
 
 /*-
  * Copyright (c) 2006 The NetBSD Foundation, Inc.
@@ -50,6 +50,8 @@
 
 void mime_fio_copy(FILE *, FILE *, void *);
 
+ssize_t mime_rfc2047_decode(char, char *, size_t, const char *, size_t);
+
 #include "mime.h"
 
 /* This is also declared in mime.h for export to complete.c. */
diff -r 5e7932c80ec9 -r f6733ea83ab0 usr.bin/mail/mime_header.c
--- a/usr.bin/mail/mime_header.c        Thu Feb 14 17:12:23 2013 +0000
+++ b/usr.bin/mail/mime_header.c        Thu Feb 14 18:23:45 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mime_header.c,v 1.8 2009/04/10 13:08:25 christos Exp $ */
+/*     $NetBSD: mime_header.c,v 1.9 2013/02/14 18:23:45 christos Exp $ */
 
 /*-
  * Copyright (c) 2006 The NetBSD Foundation, Inc.
@@ -39,7 +39,7 @@
 
 #include <sys/cdefs.h>
 #ifndef __lint__
-__RCSID("$NetBSD: mime_header.c,v 1.8 2009/04/10 13:08:25 christos Exp $");
+__RCSID("$NetBSD: mime_header.c,v 1.9 2013/02/14 18:23:45 christos Exp $");
 #endif /* not __lint__ */
 
 #include <assert.h>
@@ -53,68 +53,6 @@
 #include "mime_header.h"
 #include "mime_codecs.h"
 
-/*
- * Our interface to mime_b64tobin()
- *
- * XXX - This should move to mime_codecs.c.
- */
-static ssize_t
-mime_B64_decode(char *outbuf, size_t outlen, const char *inbuf, size_t inlen)
-{
-       if (outlen < 3 * roundup(inlen, 4) / 4)
-               return -1;
-
-       return mime_b64tobin(outbuf, inbuf, inlen);
-}
-
-
-/*
- * Header specific "quoted-printable" decode!
- * Differences with body QP decoding (see rfc 2047, sec 4.2):
- * 1) '=' occurs _only_ when followed by two hex digits (FWS is not allowed).
- * 2) Spaces can be encoded as '_' in headers for readability.
- *
- * XXX - This should move to mime_codecs.c.
- */
-static ssize_t
-mime_QPh_decode(char *outbuf, size_t outlen, const char *inbuf, size_t inlen)
-{
-       const char *p, *inend;
-       char *outend;
-       char *q;
-
-       outend = outbuf + outlen;
-       inend = inbuf + inlen;
-       q = outbuf;
-       for (p = inbuf; p < inend; p++) {
-               if (q >= outend)
-                       return -1;
-               if (*p == '=') {
-                       p++;
-                       if (p + 1 < inend) {
-                               size_t c;
-                               char *bufend;
-                               char buf[3];
-
-                               buf[0] = *p++;
-                               buf[1] = *p;
-                               buf[2] = '\0';
-                               c = strtol(buf, &bufend, 16);
-                               if (bufend != &buf[2])
-                                       return -1;
-                               *q++ = (char)c;
-                       }
-                       else
-                               return -1;
-               }
-               else if (*p == '_')  /* header's may encode ' ' as '_' */
-                       *q++ = ' ';
-               else
-                       *q++ = *p;
-       }
-       return q - outbuf;
-}
-
 static const char *
 grab_charset(char *from_cs, size_t from_cs_len, const char *p)
 {
@@ -190,13 +128,7 @@
        dstend = to_cs ? decword : *obuf;
        dstlen = (to_cs ? sizeof(decword) : (size_t)(oend - *obuf)) - 1;
 
-       if (enctype == 'B' || enctype == 'b')
-               declen = mime_B64_decode(dstend, dstlen, encword, enclen);
-       else if (enctype == 'Q' || enctype == 'q')
-               declen = mime_QPh_decode(dstend, dstlen, encword, enclen);
-       else
-               return -1;
-
+       declen = mime_rfc2047_decode(enctype, dstend, dstlen, encword, enclen);
        if (declen == -1)
                return -1;