diff --git a/NEWS b/NEWS
index eaa175ba..23e5652c 100644
--- a/NEWS
+++ b/NEWS
@@ -328,6 +328,7 @@ To be released as 0.11.4.
 * minor bug 461: ensure contrast in blank areas, to keep the cursor visible
 * minor bug 928: properly display no-break spaces in a UTF-8 document
   if the terminal uses some other charset
+* minor: don't assume sizeof(int)==4 in bittorrent
 * trivial bug 947: document.html.wrap_nbsp also affects text in tables
 * trivial bug 997: fix unlikely stack corruption in active FTP
 * build bug 950: fix ``config/install-sh: No such file or directory''
diff --git a/src/document/css/css.c b/src/document/css/css.c
index 4bc80ea3..fdd4dded 100644
--- a/src/document/css/css.c
+++ b/src/document/css/css.c
@@ -150,7 +150,7 @@ import_css(struct css_stylesheet *css, struct uri *uri)
 
 static void
 import_css_file(struct css_stylesheet *css, struct uri *base_uri,
-		unsigned char *url, int urllen)
+		const unsigned char *url, int urllen)
 {
 	struct string string, filename;
 
diff --git a/src/document/css/scanner.c b/src/document/css/scanner.c
index cb927a2f..361b1a41 100644
--- a/src/document/css/scanner.c
+++ b/src/document/css/scanner.c
@@ -158,7 +158,7 @@ scan_css_token(struct scanner *scanner, struct scanner_token *token)
 			type = CSS_TOKEN_NUMBER;
 
 		} else {
-			unsigned char *ident = string;
+			const unsigned char *ident = string;
 
 			scan_css(scanner, string, CSS_CHAR_IDENT);
 			type = map_scanner_string(scanner, ident, string,
@@ -251,7 +251,7 @@ scan_css_token(struct scanner *scanner, struct scanner_token *token)
 	} else if (first_char == '@') {
 		/* Compose token containing @<ident> */
 		if (is_css_ident_start(*string)) {
-			unsigned char *ident = string;
+			const unsigned char *ident = string;
 
 			/* Scan both ident start and ident */
 			scan_css(scanner, string, CSS_CHAR_IDENT);
diff --git a/src/document/css/stylesheet.c b/src/document/css/stylesheet.c
index a0ec6903..7cdd14a6 100644
--- a/src/document/css/stylesheet.c
+++ b/src/document/css/stylesheet.c
@@ -50,7 +50,7 @@ struct css_selector *
 init_css_selector(struct css_selector_set *sels,
                   enum css_selector_type type,
                   enum css_selector_relation relation,
-                  unsigned char *name, int namelen)
+                  const unsigned char *name, int namelen)
 {
 	struct css_selector *selector;
 
@@ -97,7 +97,7 @@ struct css_selector *
 get_css_selector(struct css_selector_set *sels,
                  enum css_selector_type type,
                  enum css_selector_relation rel,
-                 unsigned char *name, int namelen)
+                 const unsigned char *name, int namelen)
 {
 	struct css_selector *selector = NULL;
 
diff --git a/src/document/css/stylesheet.h b/src/document/css/stylesheet.h
index 79602307..01f0e9e5 100644
--- a/src/document/css/stylesheet.h
+++ b/src/document/css/stylesheet.h
@@ -96,7 +96,7 @@ struct css_selector {
 
 struct css_stylesheet;
 typedef void (*css_stylesheet_importer_T)(struct css_stylesheet *, struct uri *,
-					unsigned char *url, int urllen);
+					  const unsigned char *url, int urllen);
 
 /** The struct css_stylesheet describes all the useful data that was extracted
  * from the CSS source. Currently we don't cache anything but the default user
@@ -140,7 +140,7 @@ void done_css_stylesheet(struct css_stylesheet *css);
 struct css_selector *get_css_selector(struct css_selector_set *set,
                                       enum css_selector_type type,
                                       enum css_selector_relation rel,
-                                      unsigned char *name, int namelen);
+                                      const unsigned char *name, int namelen);
 
 #define get_css_base_selector(stylesheet, type, rel, name, namelen) \
 	get_css_selector((stylesheet) ? &(stylesheet)->selectors : NULL, \
@@ -161,7 +161,7 @@ struct css_selector *find_css_selector(struct css_selector_set *set,
 struct css_selector *init_css_selector(struct css_selector_set *set,
                                        enum css_selector_type type,
                                        enum css_selector_relation relation,
-                                       unsigned char *name, int namelen);
+                                       const unsigned char *name, int namelen);
 
 /** Add all properties from the list to the given @a selector. */
 void add_selector_properties(struct css_selector *selector,
diff --git a/src/document/css/value.c b/src/document/css/value.c
index e08960b8..a58f0521 100644
--- a/src/document/css/value.c
+++ b/src/document/css/value.c
@@ -40,7 +40,7 @@ css_parse_color_value(struct css_property_info *propinfo,
 			/* The first two args are terminated by ',' and the
 			 * last one by ')'. */
 			unsigned char paskynator = shift ? ',' : ')';
-			unsigned char *nstring = token->string;
+			const unsigned char *nstring = token->string;
 			int part;
 
 			/* Are the current and next token valid? */
diff --git a/src/document/html/internal.h b/src/document/html/internal.h
index c656660f..ff2224e2 100644
--- a/src/document/html/internal.h
+++ b/src/document/html/internal.h
@@ -143,6 +143,6 @@ unsigned char *get_target(struct document_options *options, unsigned char *a);
 
 void
 import_css_stylesheet(struct css_stylesheet *css, struct uri *base_uri,
-		      unsigned char *url, int len);
+		      const unsigned char *unterminated_url, int len);
 
 #endif
diff --git a/src/document/html/parser.c b/src/document/html/parser.c
index 54fe6d52..ecafb631 100644
--- a/src/document/html/parser.c
+++ b/src/document/html/parser.c
@@ -188,9 +188,10 @@ add_fragment_identifier(struct html_context *html_context,
 #ifdef CONFIG_CSS
 void
 import_css_stylesheet(struct css_stylesheet *css, struct uri *base_uri,
-		      unsigned char *url, int len)
+		      const unsigned char *unterminated_url, int len)
 {
 	struct html_context *html_context = css->import_data;
+	unsigned char *url;
 	unsigned char *import_url;
 	struct uri *uri;
 
@@ -201,7 +202,9 @@ import_css_stylesheet(struct css_stylesheet *css, struct uri *base_uri,
 	    || !html_context->options->css_import)
 		return;
 
-	url = memacpy(url, len);
+	/* unterminated_url might not end with '\0', but join_urls
+	 * requires that, so make a copy.  */
+	url = memacpy(unterminated_url, len);
 	if (!url) return;
 
 	/* HTML <head> urls should already be fine but we can.t detect them. */
diff --git a/src/protocol/bittorrent/bencoding.c b/src/protocol/bittorrent/bencoding.c
index 237f3af7..7f0b320d 100644
--- a/src/protocol/bittorrent/bencoding.c
+++ b/src/protocol/bittorrent/bencoding.c
@@ -327,7 +327,7 @@ check_bencoding_dictionary_entry(struct scanner *scanner,
 static off_t
 parse_bencoding_integer(struct scanner_token *token)
 {
-	unsigned char *string = token->string;
+	const unsigned char *string = token->string;
 	int pos = 0, length = token->length;
 	off_t integer = 0;
 	int sign = 1;
@@ -340,9 +340,13 @@ parse_bencoding_integer(struct scanner_token *token)
 	}
 
 	for (; pos < length && isdigit(string[pos]); pos++) {
-		if (integer > (off_t) integer * 10)
+		off_t newint = integer * 10 + string[pos] - '0';
+
+		/* Check for overflow.  This assumes wraparound,
+		 * even though C does not guarantee that.  */
+		if (newint / 10 != integer)
 			return 0;
-		integer = (off_t) integer * 10 + string[pos] - '0';
+		integer = newint;
 	}
 
 	if (sign == -1)
@@ -352,7 +356,8 @@ parse_bencoding_integer(struct scanner_token *token)
 }
 
 static unsigned char *
-normalize_bencoding_path(unsigned char *path, int pathlen, int *malicious)
+normalize_bencoding_path(const unsigned char *path, int pathlen,
+			 int *malicious)
 {
 	struct string string;
 
@@ -735,7 +740,7 @@ parse_bittorrent_metafile(struct bittorrent_meta *meta, struct string *metafile)
 
 		case BENCODING_TOKEN_INFO:
 		{
-			unsigned char *start = value->string;
+			const unsigned char *start = value->string;
 			struct scanner_token *token;
 			enum bittorrent_state state;
 
@@ -881,8 +886,9 @@ parse_bencoding_peers_string(struct bittorrent_connection *bittorrent,
 			     struct scanner *scanner)
 {
 	struct scanner_token *token = get_scanner_token(scanner);
-	unsigned char *pos;
-	unsigned char *last_peer_info_start = token->string + token->length - 6;
+	const unsigned char *pos;
+	const unsigned char *last_peer_info_start
+		= token->string + token->length - 6;
 	enum bittorrent_state state = BITTORRENT_STATE_OK;
 
 	assert(get_scanner_token(scanner)->type == BENCODING_TOKEN_STRING);
diff --git a/src/protocol/bittorrent/common.c b/src/protocol/bittorrent/common.c
index d9fe3ecb..a0a9ec1c 100644
--- a/src/protocol/bittorrent/common.c
+++ b/src/protocol/bittorrent/common.c
@@ -213,7 +213,7 @@ get_peer_from_bittorrent_pool(struct bittorrent_connection *bittorrent,
 enum bittorrent_state
 add_peer_to_bittorrent_pool(struct bittorrent_connection *bittorrent,
 			    bittorrent_id_T id, int port,
-			    unsigned char *ip, int iplen)
+			    const unsigned char *ip, int iplen)
 {
 	struct bittorrent_peer *peer;
 
diff --git a/src/protocol/bittorrent/common.h b/src/protocol/bittorrent/common.h
index 5ea507e1..9d44b761 100644
--- a/src/protocol/bittorrent/common.h
+++ b/src/protocol/bittorrent/common.h
@@ -368,7 +368,7 @@ bittorrent_id_is_known(struct bittorrent_connection *bittorrent,
 enum bittorrent_state
 add_peer_to_bittorrent_pool(struct bittorrent_connection *bittorrent,
 			    bittorrent_id_T id, int port,
-			    unsigned char *ip, int iplen);
+			    const unsigned char *ip, int iplen);
 
 struct bittorrent_peer *
 get_peer_from_bittorrent_pool(struct bittorrent_connection *bittorrent,
diff --git a/src/protocol/bittorrent/piececache.c b/src/protocol/bittorrent/piececache.c
index 3ef61c5b..f448a868 100644
--- a/src/protocol/bittorrent/piececache.c
+++ b/src/protocol/bittorrent/piececache.c
@@ -1080,7 +1080,7 @@ bittorrent_resume_writer(void *data, int fd)
 	uint32_t piece;
 
 	memcpy(&metafile.length, data, sizeof(metafile.length));
-	metafile.source = (unsigned char *) data + 4;
+	metafile.source = (unsigned char *) data + sizeof(metafile.length);
 
 	if (parse_bittorrent_metafile(&meta, &metafile) != BITTORRENT_STATE_OK) {
 		done_bittorrent_meta(&meta);
diff --git a/src/util/color.c b/src/util/color.c
index 5b7872a5..d6684ebb 100644
--- a/src/util/color.c
+++ b/src/util/color.c
@@ -82,7 +82,7 @@ free_colors_lookup(void)
 }
 
 int
-decode_color(unsigned char *str, int slen, color_T *color)
+decode_color(const unsigned char *str, int slen, color_T *color)
 {
 	if (*str == '#' && (slen == 7 || slen == 4)) {
 		unsigned char buffer[7];
diff --git a/src/util/color.h b/src/util/color.h
index 80ad9f8b..52f7353c 100644
--- a/src/util/color.h
+++ b/src/util/color.h
@@ -13,7 +13,7 @@ struct color_pair {
 /** Decode the color string.
  * The color string can either contain '@#FF0044' style declarations or
  * color names. */
-int decode_color(unsigned char *str, int slen, color_T *color);
+int decode_color(const unsigned char *str, int slen, color_T *color);
 
 /** Returns a string containing the color info. If no 'English' name can be
  * found the hex color (@#rrggbb) is returned in the given buffer. */
diff --git a/src/util/fastfind.c b/src/util/fastfind.c
index 9279dc59..17ac97ed 100644
--- a/src/util/fastfind.c
+++ b/src/util/fastfind.c
@@ -590,7 +590,8 @@ return_error:
 } while (0)
 
 void *
-fastfind_search(struct fastfind_index *index, unsigned char *key, int key_len)
+fastfind_search(struct fastfind_index *index,
+		const unsigned char *key, int key_len)
 {
 	struct ff_node *current;
 	struct fastfind_info *info;
diff --git a/src/util/fastfind.h b/src/util/fastfind.h
index 27a03407..a6b85585 100644
--- a/src/util/fastfind.h
+++ b/src/util/fastfind.h
@@ -49,7 +49,8 @@ struct fastfind_index *fastfind_index(struct fastfind_index *index, enum fastfin
 /** Search the index for @a key with length @a key_len using the
  * @a index' handle created with fastfind_index().
  * @relates fastfind_index */
-void *fastfind_search(struct fastfind_index *index, unsigned char *key, int key_len);
+void *fastfind_search(struct fastfind_index *index,
+		      const unsigned char *key, int key_len);
 
 /** Fastfind cleanup. It frees the given @a index.
  * Must be called once per list.
diff --git a/src/util/scanner.c b/src/util/scanner.c
index d2440967..1545745f 100644
--- a/src/util/scanner.c
+++ b/src/util/scanner.c
@@ -17,7 +17,8 @@
 
 int
 map_scanner_string(struct scanner *scanner,
-		   unsigned char *ident, unsigned char *end, int base_type)
+		   const unsigned char *ident, const unsigned char *end,
+		   int base_type)
 {
 	const struct scanner_string_mapping *mappings = scanner->info->mappings;
 	int length = end - ident;
diff --git a/src/util/scanner.h b/src/util/scanner.h
index 7949507a..a8846258 100644
--- a/src/util/scanner.h
+++ b/src/util/scanner.h
@@ -190,7 +190,8 @@ skip_scanner_tokens(struct scanner *scanner, int skipto, int precedence);
  * @relates scanner */
 int
 map_scanner_string(struct scanner *scanner,
-		   unsigned char *ident, unsigned char *end, int base_type);
+		   const unsigned char *ident, const unsigned char *end,
+		   int base_type);
 
 #ifdef DEBUG_SCANNER
 /** @relates scanner */