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Commitbe8b06c

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Revoke support for strxfrm() that write past the specified array length.
This formalizes a decision implicit in commit4ea51cd and adds clean detection ofaffected systems. Vendor updates are available for each such known bug.Back-patch to 9.5, where the aforementioned commit first appeared.
1 parentb28244a commitbe8b06c

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5 files changed

+70
-10
lines changed

5 files changed

+70
-10
lines changed

‎src/backend/main/main.c

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Original file line numberDiff line numberDiff line change
@@ -149,6 +149,8 @@ main(int argc, char *argv[])
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*/
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unsetenv("LC_ALL");
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check_strxfrm_bug();
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/*
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* Catch standard options before doing much else, in particular before we
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* insist on not being root.

‎src/backend/utils/adt/pg_locale.c

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Original file line numberDiff line numberDiff line change
@@ -854,6 +854,64 @@ IsoLocaleName(const char *winlocname)
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#endif/* WIN32 && LC_MESSAGES */
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856856

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/*
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* Detect aging strxfrm() implementations that, in a subset of locales, write
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* past the specified buffer length. Affected users must update OS packages
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* before using PostgreSQL 9.5 or later.
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*
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* Assume that the bug can come and go from one postmaster startup to another
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* due to physical replication among diverse machines. Assume that the bug's
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* presence will not change during the life of a particular postmaster. Given
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* those assumptions, call this no less than once per postmaster startup per
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* LC_COLLATE setting used. No known-affected system offers strxfrm_l(), so
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* there is no need to consider pg_collation locales.
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*/
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void
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check_strxfrm_bug(void)
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{
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charbuf[32];
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constintcanary=0x7F;
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boolok= true;
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/*
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* Given a two-byte ASCII string and length limit 7, 8 or 9, Solaris 10
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* 05/08 returns 18 and modifies 10 bytes. It respects limits above or
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* below that range.
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*
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* The bug is present in Solaris 8 as well; it is absent in Solaris 10
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* 01/13 and Solaris 11.2. Affected locales include is_IS.ISO8859-1,
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* en_US.UTF-8, en_US.ISO8859-1, and ru_RU.KOI8-R. Unaffected locales
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* include de_DE.UTF-8, de_DE.ISO8859-1, zh_TW.UTF-8, and C.
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*/
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buf[7]=canary;
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(void)strxfrm(buf,"ab",7);
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if (buf[7]!=canary)
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ok= false;
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/*
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* illumos bug #1594 was present in the source tree from 2010-10-11 to
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* 2012-02-01. Given an ASCII string of any length and length limit 1,
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* affected systems ignore the length limit and modify a number of bytes
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* one less than the return value. The problem inputs for this bug do not
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* overlap those for the Solaris bug, hence a distinct test.
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*
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* Affected systems include smartos-20110926T021612Z. Affected locales
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* include en_US.ISO8859-1 and en_US.UTF-8. Unaffected locales include C.
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*/
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buf[1]=canary;
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(void)strxfrm(buf,"a",1);
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if (buf[1]!=canary)
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ok= false;
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if (!ok)
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ereport(ERROR,
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(errcode(ERRCODE_SYSTEM_ERROR),
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errmsg_internal("strxfrm(), in locale \"%s\", writes past the specified array length",
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setlocale(LC_COLLATE,NULL)),
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errhint("Apply system library package updates.")));
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}
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/*
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* Cache mechanism for collation information.
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*

‎src/backend/utils/adt/selfuncs.c

Lines changed: 7 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -3932,16 +3932,8 @@ convert_string_datum(Datum value, Oid typid)
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size_txfrmlen2PG_USED_FOR_ASSERTS_ONLY;
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/*
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* Note: originally we guessed at a suitable output buffer size, and
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* only needed to call strxfrm twice if our guess was too small.
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* However, it seems that some versions of Solaris have buggy strxfrm
3938-
* that can write past the specified buffer length in that scenario.
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* So, do it the dumb way for portability.
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*
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* Yet other systems (e.g., glibc) sometimes return a smaller value
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* from the second call than the first; thus the Assert must be <= not
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* == as you'd expect. Can't any of these people program their way
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* out of a paper bag?
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* XXX: We could guess at a suitable output buffer size and only call
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* strxfrm twice if our guess is too small.
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*
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* XXX: strxfrm doesn't support UTF-8 encoding on Win32, it can return
39473939
* bogus data or set an error. This is not really a problem unless it
@@ -3974,6 +3966,11 @@ convert_string_datum(Datum value, Oid typid)
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#endif
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xfrmstr= (char*)palloc(xfrmlen+1);
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xfrmlen2=strxfrm(xfrmstr,val,xfrmlen+1);
3969+
3970+
/*
3971+
* Some systems (e.g., glibc) can return a smaller value from the
3972+
* second call than the first; thus the Assert must be <= not ==.
3973+
*/
39773974
Assert(xfrmlen2 <=xfrmlen);
39783975
pfree(val);
39793976
val=xfrmstr;

‎src/backend/utils/init/postinit.c

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -391,6 +391,8 @@ CheckMyDatabase(const char *name, bool am_superuser)
391391
SetConfigOption("lc_collate",collate,PGC_INTERNAL,PGC_S_OVERRIDE);
392392
SetConfigOption("lc_ctype",ctype,PGC_INTERNAL,PGC_S_OVERRIDE);
393393

394+
check_strxfrm_bug();
395+
394396
ReleaseSysCache(tup);
395397
}
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‎src/include/utils/pg_locale.h

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Original file line numberDiff line numberDiff line change
@@ -44,6 +44,7 @@ extern void assign_locale_time(const char *newval, void *extra);
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externboolcheck_locale(intcategory,constchar*locale,char**canonname);
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externchar*pg_perm_setlocale(intcategory,constchar*locale);
47+
externvoidcheck_strxfrm_bug(void);
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externboollc_collate_is_c(Oidcollation);
4950
externboollc_ctype_is_c(Oidcollation);

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