diff options
| -rw-r--r-- | src/src/pdkim/pdkim.c | 212 |
1 files changed, 172 insertions, 40 deletions
diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c index 4f0da3f71..30b81c4b4 100644 --- a/src/src/pdkim/pdkim.c +++ b/src/src/pdkim/pdkim.c @@ -231,6 +231,7 @@ char *pdkim_strncat(pdkim_str *str, const char *data, int len) { char *pdkim_strcat(pdkim_str *str, const char *cstr) { return pdkim_strncat(str, cstr, strlen(cstr)); } + char *pdkim_numcat(pdkim_str *str, unsigned long num) { char minibuf[20]; snprintf(minibuf,20,"%lu",num); @@ -1195,86 +1196,216 @@ DLLEXPORT int pdkim_feed (pdkim_ctx *ctx, return PDKIM_OK; } +/* + * RFC 5322 specifies that header line length SHOULD be no more than 78 + * lets make it so! + * pdkim_headcat + * returns char* + * + * col: this int holds and receives column number (octets since last '\n') + * str: partial string to append to + * pad: padding, split line or space after before or after eg: ";" + * intro: - must join to payload eg "h=", usually the tag name + * payload: eg base64 data - long data can be split arbitrarily. + * + * this code doesn't fold the header in some of the places that RFC4871 + * allows: As per RFC5322(2.2.3) it only folds before or after tag-value + * pairs and inside long values. it also always spaces or breaks after the + * "pad" + * + * no guarantees are made for output given out-of range input. like tag + * names loinger than 78, or bogus col. Input is assumed to be free of line breaks. + */ + +static char *pdkim_headcat(int *col, pdkim_str *str, const char*pad,const char *intro, const char *payload ) { + size_t l; + if( pad) + { + l = strlen(pad); + if( *col + l > 78 ) + { + pdkim_strcat(str, "\r\n\t"); + *col=1; + } + pdkim_strncat(str, pad,l); + *col +=l; + } + + l=(pad?1:0) + (intro?strlen(intro):0 ); + + if( *col + l > 78 ) + { /*can't fit intro - start a new line to make room.*/ + pdkim_strcat(str, "\r\n\t"); + *col=1; + l= intro?strlen(intro):0; + } + + l += payload ? strlen(payload):0 ; + + while(l>77) + { /* this fragment will not fit on a single line */ + if( pad ) + { + pdkim_strcat(str, " "); + *col +=1; + pad=NULL; // only want this once + l--; + } + if( intro ) + { + size_t sl=strlen(intro); + pdkim_strncat(str, intro,sl); + *col +=sl; + l-=sl; + intro=NULL; // only want this once + } + if(payload) + { + size_t sl=strlen(payload); + size_t chomp = *col+sl < 77 ? sl : 78-*col; + pdkim_strncat(str, payload,chomp); + *col +=chomp; + payload+=chomp; + l-=chomp-1; + } + // the while precondition tells us it didn't fit. + pdkim_strcat(str, "\r\n\t"); + *col=1; + } + if( *col + l > 78 ) + { + pdkim_strcat(str, "\r\n\t"); + *col=1; + pad=NULL; + } + + if( pad ) + { + pdkim_strcat(str, " "); + *col +=1; + pad=NULL; + } + + if( intro ) + { + size_t sl=strlen(intro); + pdkim_strncat(str, intro,sl); + *col +=sl; + l-=sl; + intro=NULL; + } + if(payload) + { + size_t sl=strlen(payload); + pdkim_strncat(str, payload,sl); + *col +=sl; + } + + return str->str; +} /* -------------------------------------------------------------------------- */ char *pdkim_create_header(pdkim_signature *sig, int final) { char *rc = NULL; char *base64_bh = NULL; char *base64_b = NULL; + int col=0; pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); if (hdr == NULL) return NULL; + pdkim_str *canon_all = pdkim_strnew(pdkim_canons[sig->canon_headers]); + if (canon_all == NULL) goto BAIL; base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len); if (base64_bh == NULL) goto BAIL; + col=strlen(hdr->str); + /* Required and static bits */ if ( - pdkim_strcat(hdr,"; a=") && - pdkim_strcat(hdr,pdkim_algos[sig->algo]) && - pdkim_strcat(hdr,"; q=") && - pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod]) && - pdkim_strcat(hdr,"; c=") && - pdkim_strcat(hdr,pdkim_canons[sig->canon_headers]) && - pdkim_strcat(hdr,"/") && - pdkim_strcat(hdr,pdkim_canons[sig->canon_body]) && - pdkim_strcat(hdr,"; d=") && - pdkim_strcat(hdr,sig->domain) && - pdkim_strcat(hdr,"; s=") && - pdkim_strcat(hdr,sig->selector) && - pdkim_strcat(hdr,";\r\n\th=") && - pdkim_strcat(hdr,sig->headernames) && - pdkim_strcat(hdr,"; bh=") && - pdkim_strcat(hdr,base64_bh) && - pdkim_strcat(hdr,";\r\n\t") + pdkim_headcat(&col,hdr,";","a=",pdkim_algos[sig->algo]) && + pdkim_headcat(&col,hdr,";","q=",pdkim_querymethods[sig->querymethod]) && + pdkim_strcat(canon_all,"/") && + pdkim_strcat(canon_all,pdkim_canons[sig->canon_body]) && + pdkim_headcat(&col,hdr,";","c=",canon_all->str) && + pdkim_headcat(&col,hdr,";","d=",sig->domain) && + pdkim_headcat(&col,hdr,";","s=",sig->selector) ) { + /* list of eader names can be split between items. */ + { + char *n=strdup(sig->headernames); + char *f=n; + char *i="h="; + char *s=";"; + if(!n) goto BAIL; + while (*n) + { + char *c=strchr(n,':'); + if(c) *c='\0'; + if(!i) + { + if (!pdkim_headcat(&col,hdr,NULL,NULL,":")) + { + free(f); + goto BAIL; + } + } + if( !pdkim_headcat(&col,hdr,s,i,n)) + { + free(f); + goto BAIL; + } + if(c) n=c+1 ; else break; + s=NULL; + i=NULL; + } + free(f); + } + if(!pdkim_headcat(&col,hdr,";","bh=",base64_bh)) + goto BAIL; + /* Optional bits */ if (sig->identity != NULL) { - if (!( pdkim_strcat(hdr,"i=") && - pdkim_strcat(hdr,sig->identity) && - pdkim_strcat(hdr,";") ) ) { + if(!pdkim_headcat(&col,hdr,";","i=",sig->identity)){ goto BAIL; } } + if (sig->created > 0) { - if (!( pdkim_strcat(hdr,"t=") && - pdkim_numcat(hdr,sig->created) && - pdkim_strcat(hdr,";") ) ) { + char minibuf[20]; + snprintf(minibuf,20,"%lu",sig->created); + if(!pdkim_headcat(&col,hdr,";","t=",minibuf)) { goto BAIL; } } if (sig->expires > 0) { - if (!( pdkim_strcat(hdr,"x=") && - pdkim_numcat(hdr,sig->expires) && - pdkim_strcat(hdr,";") ) ) { + char minibuf[20]; + snprintf(minibuf,20,"%lu",sig->expires); + if(!pdkim_headcat(&col,hdr,";","x=",minibuf)) { goto BAIL; } } if (sig->bodylength >= 0) { - if (!( pdkim_strcat(hdr,"l=") && - pdkim_numcat(hdr,sig->bodylength) && - pdkim_strcat(hdr,";") ) ) { + char minibuf[20]; + snprintf(minibuf,20,"%lu",sig->bodylength); + if(!pdkim_headcat(&col,hdr,";","l=",minibuf)) { goto BAIL; } } - /* Extra linebreak */ - if (hdr->str[(hdr->len)-1] == ';') { - if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL; - } + /* Preliminary or final version? */ if (final) { base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len); if (base64_b == NULL) goto BAIL; - if ( - pdkim_strcat(hdr,"b=") && - pdkim_strcat(hdr,base64_b) && - pdkim_strcat(hdr,";") - ) goto DONE; + if(!pdkim_headcat(&col,hdr,";","b=",base64_b)) goto BAIL; } else { - if (pdkim_strcat(hdr,"b=;")) goto DONE; + if(!pdkim_headcat(&col,hdr,";","b=","")) goto BAIL; } - goto BAIL; + /* add trailing semicolon: I'm not sure if this is actually needed */ + if(!pdkim_headcat(&col,hdr,NULL,";","")) goto BAIL; + + goto DONE; } DONE: @@ -1282,6 +1413,7 @@ char *pdkim_create_header(pdkim_signature *sig, int final) { BAIL: pdkim_strfree(hdr); + if (canon_all != NULL) pdkim_strfree(canon_all); if (base64_bh != NULL) free(base64_bh); if (base64_b != NULL) free(base64_b); return rc; |