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Commit8488f25

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committed
Upgrade parsing code for ACLs to be less hokey and more cognizant of
the actual logical structure and quoting rules being used. Fixes bugreported by Chris K-L on 7/8/03.
1 parent1c6eba4 commit8488f25

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1 file changed

+151
-36
lines changed

1 file changed

+151
-36
lines changed

‎src/bin/pg_dump/dumputils.c‎

Lines changed: 151 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Header: /cvsroot/pgsql/src/bin/pg_dump/dumputils.c,v 1.5 2003/07/24 15:52:53 petere Exp $
10+
* $Header: /cvsroot/pgsql/src/bin/pg_dump/dumputils.c,v 1.6 2003/07/31 17:21:57 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -19,12 +19,15 @@
1919
#include"parser/keywords.h"
2020

2121

22+
#definesupports_grant_options(version) ((version) >= 70400)
23+
24+
staticboolparseAclArray(constchar*acls,char***itemarray,int*nitems);
2225
staticboolparseAclItem(constchar*item,constchar*type,constchar*name,
2326
intremoteVersion,
2427
PQExpBuffergrantee,PQExpBuffergrantor,
2528
PQExpBufferprivs,PQExpBufferprivswgo);
29+
staticchar*copyAclUserName(PQExpBufferoutput,char*input);
2630
staticvoidAddAcl(PQExpBufferaclbuf,constchar*keyword);
27-
#definesupports_grant_options(version) ((version) >= 70400)
2831

2932

3033
/*
@@ -185,15 +188,23 @@ buildACLCommands(const char *name, const char *type,
185188
intremoteVersion,
186189
PQExpBuffersql)
187190
{
188-
char*aclbuf,
189-
*tok;
191+
char**aclitems;
192+
intnaclitems;
193+
inti;
190194
PQExpBuffergrantee,grantor,privs,privswgo;
191195
PQExpBufferfirstsql,secondsql;
192196
boolfound_owner_privs= false;
193197

194198
if (strlen(acls)==0)
195199
return true;/* object has default permissions */
196200

201+
if (!parseAclArray(acls,&aclitems,&naclitems))
202+
{
203+
if (aclitems)
204+
free(aclitems);
205+
return false;
206+
}
207+
197208
grantee=createPQExpBuffer();
198209
grantor=createPQExpBuffer();
199210
privs=createPQExpBuffer();
@@ -217,27 +228,10 @@ buildACLCommands(const char *name, const char *type,
217228
appendPQExpBuffer(firstsql,"REVOKE ALL ON %s %s FROM PUBLIC;\n",
218229
type,name);
219230

220-
/* Make a working copy of acls so we can use strtok */
221-
aclbuf=strdup(acls);
222-
223-
/* Scan comma-separated ACL items */
224-
for (tok=strtok(aclbuf,",");tok!=NULL;tok=strtok(NULL,","))
231+
/* Scan individual ACL items */
232+
for (i=0;i<naclitems;i++)
225233
{
226-
size_ttoklen;
227-
228-
/*
229-
* Token may start with '{' and/or '"'. Actually only the start
230-
* of the string should have '{', but we don't verify that.
231-
*/
232-
if (*tok=='{')
233-
tok++;
234-
if (*tok=='"')
235-
tok++;
236-
toklen=strlen(tok);
237-
while (toklen >=0&& (tok[toklen-1]=='"'||tok[toklen-1]=='}'))
238-
tok[toklen---1]='\0';
239-
240-
if (!parseAclItem(tok,type,name,remoteVersion,
234+
if (!parseAclItem(aclitems[i],type,name,remoteVersion,
241235
grantee,grantor,privs,privswgo))
242236
return false;
243237

@@ -327,7 +321,6 @@ buildACLCommands(const char *name, const char *type,
327321
type,name,fmtId(owner));
328322
}
329323

330-
free(aclbuf);
331324
destroyPQExpBuffer(grantee);
332325
destroyPQExpBuffer(grantor);
333326
destroyPQExpBuffer(privs);
@@ -337,15 +330,105 @@ buildACLCommands(const char *name, const char *type,
337330
destroyPQExpBuffer(firstsql);
338331
destroyPQExpBuffer(secondsql);
339332

333+
free(aclitems);
334+
340335
return true;
341336
}
342337

338+
/*
339+
* Deconstruct an ACL array (or actually any 1-dimensional Postgres array)
340+
* into individual items.
341+
*
342+
* On success, returns true and sets *itemarray and *nitems to describe
343+
* an array of individual strings. On parse failure, returns false;
344+
* *itemarray may exist or be NULL.
345+
*
346+
* NOTE: free'ing itemarray is sufficient to deallocate the working storage.
347+
*/
348+
staticbool
349+
parseAclArray(constchar*acls,char***itemarray,int*nitems)
350+
{
351+
intinputlen;
352+
char**items;
353+
char*strings;
354+
intcuritem;
355+
356+
/*
357+
* We expect input in the form of "{item,item,item}" where any item
358+
* is either raw data, or surrounded by double quotes (in which case
359+
* embedded characters including backslashes and quotes are backslashed).
360+
*
361+
* We build the result as an array of pointers followed by the actual
362+
* string data, all in one malloc block for convenience of deallocation.
363+
* The worst-case storage need is not more than one pointer and one
364+
* character for each input character (consider "{,,,,,,,,,,}").
365+
*/
366+
*itemarray=NULL;
367+
*nitems=0;
368+
inputlen=strlen(acls);
369+
if (inputlen<2||acls[0]!='{'||acls[inputlen-1]!='}')
370+
return false;/* bad input */
371+
items= (char**)malloc(inputlen* (sizeof(char*)+sizeof(char)));
372+
if (items==NULL)
373+
return false;/* out of memory */
374+
*itemarray=items;
375+
strings= (char*) (items+inputlen);
376+
377+
acls++;/* advance over initial '{' */
378+
curitem=0;
379+
while (*acls!='}')
380+
{
381+
if (*acls=='\0')
382+
return false;/* premature end of string */
383+
items[curitem]=strings;
384+
while (*acls!='}'&&*acls!=',')
385+
{
386+
if (*acls=='\0')
387+
return false;/* premature end of string */
388+
if (*acls!='"')
389+
*strings++=*acls++;/* copy unquoted data */
390+
else
391+
{
392+
/* process quoted substring */
393+
acls++;
394+
while (*acls!='"')
395+
{
396+
if (*acls=='\0')
397+
return false;/* premature end of string */
398+
if (*acls=='\\')
399+
{
400+
acls++;
401+
if (*acls=='\0')
402+
return false;/* premature end of string */
403+
}
404+
*strings++=*acls++;/* copy quoted data */
405+
}
406+
acls++;
407+
}
408+
}
409+
*strings++='\0';
410+
if (*acls==',')
411+
acls++;
412+
curitem++;
413+
}
414+
if (acls[1]!='\0')
415+
return false;/* bogus syntax (embedded '}') */
416+
*nitems=curitem;
417+
return true;
418+
}
343419

344420
/*
345-
* This will take an aclitem string of privilege code letters and
346-
* parse it into grantee, grantor, and privilege information. The
347-
* privilege information is split between privileges with grant option
348-
* (privswgo) and without (privs).
421+
* This will parse an aclitem string, having the general form
422+
*username=privilegecodes/grantor
423+
* or
424+
*group groupname=privilegecodes/grantor
425+
* (the /grantor part will not be present if pre-7.4 database).
426+
*
427+
* The returned grantee string will be the dequoted username or groupname
428+
* (preceded with "group " in the latter case). The returned grantor is
429+
* the dequoted grantor name or empty. Privilege characters are decoded
430+
* and split between privileges with grant option (privswgo) and without
431+
* (privs).
349432
*
350433
* Note: for cross-version compatibility, it's important to use ALL when
351434
* appropriate.
@@ -365,19 +448,19 @@ parseAclItem(const char *item, const char *type, const char *name,
365448

366449
buf=strdup(item);
367450

368-
/* user name is string up to = */
369-
eqpos=strchr(buf,'=');
370-
if (!eqpos)
451+
/* useror groupname is string up to = */
452+
eqpos=copyAclUserName(grantee,buf);
453+
if (*eqpos!='=')
371454
return false;
372-
*eqpos='\0';
373-
printfPQExpBuffer(grantee,"%s",buf);
374455

375456
/* grantor may be listed after / */
376457
slpos=strchr(eqpos+1,'/');
377458
if (slpos)
378459
{
379-
*slpos='\0';
380-
printfPQExpBuffer(grantor,"%s",slpos+1);
460+
*slpos++='\0';
461+
slpos=copyAclUserName(grantor,slpos);
462+
if (*slpos!='\0')
463+
return false;
381464
}
382465
else
383466
resetPQExpBuffer(grantor);
@@ -457,6 +540,38 @@ parseAclItem(const char *item, const char *type, const char *name,
457540
return true;
458541
}
459542

543+
/*
544+
* Transfer a user or group name starting at *input into the output buffer,
545+
* dequoting if needed. Returns a pointer to just past the input name.
546+
* The name is taken to end at an unquoted '=' or end of string.
547+
*/
548+
staticchar*
549+
copyAclUserName(PQExpBufferoutput,char*input)
550+
{
551+
resetPQExpBuffer(output);
552+
while (*input&&*input!='=')
553+
{
554+
if (*input!='"')
555+
appendPQExpBufferChar(output,*input++);
556+
else
557+
{
558+
input++;
559+
while (*input!='"')
560+
{
561+
if (*input=='\0')
562+
returninput;/* really a syntax error... */
563+
/*
564+
* There is no quoting convention here, thus we can't cope
565+
* with usernames containing double quotes. Keep this code
566+
* in sync with putid() in backend's acl.c.
567+
*/
568+
appendPQExpBufferChar(output,*input++);
569+
}
570+
input++;
571+
}
572+
}
573+
returninput;
574+
}
460575

461576
/*
462577
* Append a privilege keyword to a keyword list, inserting comma if needed.

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