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Revert error-throwing wrappers for the printf family of functions.
This reverts commit 16304a0, except for its changes in src/port/snprintf.c; as well as commit cac18a7 which is no longer needed. Fujii Masao reported that the previous commit caused failures in psql on OS X, since if one exits the pager program early while viewing a query result, psql sees an EPIPE error from fprintf --- and the wrapper function thought that was reason to panic. (It's a bit surprising that the same does not happen on Linux.) Further discussion among the security list concluded that the risk of other such failures was far too great, and that the one-size-fits-all approach to error handling embodied in the previous patch is unlikely to be workable. This leaves us again exposed to the possibility of the type of failure envisioned in CVE-2015-3166. However, that failure mode is strictly hypothetical at this point: there is no concrete reason to believe that an attacker could trigger information disclosure through the supposed mechanism. In the first place, the attack surface is fairly limited, since so much of what the backend does with format strings goes through stringinfo.c or psprintf(), and those already had adequate defenses. In the second place, even granting that an unprivileged attacker could control the occurrence of ENOMEM with some precision, it's a stretch to believe that he could induce it just where the target buffer contains some valuable information. So we concluded that the risk of non-hypothetical problems induced by the patch greatly outweighs the security risks. We will therefore revert, and instead undertake closer analysis to identify specific calls that may need hardening, rather than attempt a universal solution. We have kept the portion of the previous patch that improved snprintf.c's handling of errors when it calls the platform's sprintf(). That seems to be an unalloyed improvement. Security: CVE-2015-3166
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16 files changed

+53
-251
lines changed

16 files changed

+53
-251
lines changed

‎src/include/port.h

Lines changed: 25 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -126,21 +126,19 @@ extern unsigned char pg_tolower(unsigned char ch);
126126
extern unsigned char pg_ascii_toupper(unsigned char ch);
127127
extern unsigned char pg_ascii_tolower(unsigned char ch);
128128

129+
#ifdef USE_REPL_SNPRINTF
130+
129131
/*
130-
* Capture macro-compatible calls to printf() and friends, and redirect them
131-
* to wrappers that throw errors in lieu of reporting failure in a return
132-
* value. Versions of libintl >= 0.13 similarly redirect to versions that
133-
* understand the %$ format, so disable libintl macros first.
132+
* Versions of libintl >= 0.13 try to replace printf() and friends with
133+
* macros to their own versions that understand the %$ format. We do the
134+
* same, so disable their macros, if they exist.
134135
*/
135136
#ifdef vsnprintf
136137
#undef vsnprintf
137138
#endif
138139
#ifdef snprintf
139140
#undef snprintf
140141
#endif
141-
#ifdef vsprintf
142-
#undef vsprintf
143-
#endif
144142
#ifdef sprintf
145143
#undef sprintf
146144
#endif
@@ -154,61 +152,11 @@ extern unsigned char pg_ascii_tolower(unsigned char ch);
154152
#undef printf
155153
#endif
156154

157-
extern int
158-
vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
159-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 0)));
160-
extern int
161-
snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
162-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
163-
extern int
164-
vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
165-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 0)));
166-
extern int
167-
sprintf_throw_on_fail(char *str, const char *fmt,...)
168-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
169-
extern int
170-
vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
171-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 0)));
172-
extern int
173-
fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
174-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
175-
extern int
176-
printf_throw_on_fail(const char *fmt,...)
177-
__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
178-
179-
/*
180-
* The GCC-specific code below prevents the __attribute__(... 'printf')
181-
* above from being replaced, and this is required because gcc doesn't
182-
* know anything about printf_throw_on_fail.
183-
*/
184-
#ifdef __GNUC__
185-
#define vsnprintf(...) vsnprintf_throw_on_fail(__VA_ARGS__)
186-
#define snprintf(...) snprintf_throw_on_fail(__VA_ARGS__)
187-
#define vsprintf(...) vsprintf_throw_on_fail(__VA_ARGS__)
188-
#define sprintf(...) sprintf_throw_on_fail(__VA_ARGS__)
189-
#define vfprintf(...) vfprintf_throw_on_fail(__VA_ARGS__)
190-
#define fprintf(...) fprintf_throw_on_fail(__VA_ARGS__)
191-
#define printf(...) printf_throw_on_fail(__VA_ARGS__)
192-
#else
193-
#define vsnprintf vsnprintf_throw_on_fail
194-
#define snprintf snprintf_throw_on_fail
195-
#define vsprintf vsprintf_throw_on_fail
196-
#define sprintf sprintf_throw_on_fail
197-
#define vfprintf vfprintf_throw_on_fail
198-
#define fprintf fprintf_throw_on_fail
199-
#define printf printf_throw_on_fail
200-
#endif
201-
202-
#ifdef USE_REPL_SNPRINTF
203-
204-
/* Code outside syswrap.c should not call these. */
205-
206155
extern int pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args);
207156
extern int
208157
pg_snprintf(char *str, size_t count, const char *fmt,...)
209158
/* This extension allows gcc to check the format string */
210159
__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
211-
extern int pg_vsprintf(char *str, const char *fmt, va_list args);
212160
extern int
213161
pg_sprintf(char *str, const char *fmt,...)
214162
/* This extension allows gcc to check the format string */
@@ -223,6 +171,26 @@ pg_printf(const char *fmt,...)
223171
/* This extension allows gcc to check the format string */
224172
__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
225173

174+
/*
175+
* The GCC-specific code below prevents the __attribute__(... 'printf')
176+
* above from being replaced, and this is required because gcc doesn't
177+
* know anything about pg_printf.
178+
*/
179+
#ifdef __GNUC__
180+
#define vsnprintf(...) pg_vsnprintf(__VA_ARGS__)
181+
#define snprintf(...) pg_snprintf(__VA_ARGS__)
182+
#define sprintf(...) pg_sprintf(__VA_ARGS__)
183+
#define vfprintf(...) pg_vfprintf(__VA_ARGS__)
184+
#define fprintf(...) pg_fprintf(__VA_ARGS__)
185+
#define printf(...) pg_printf(__VA_ARGS__)
186+
#else
187+
#define vsnprintf pg_vsnprintf
188+
#define snprintf pg_snprintf
189+
#define sprintf pg_sprintf
190+
#define vfprintf pg_vfprintf
191+
#define fprintf pg_fprintf
192+
#define printf pg_printf
193+
#endif
226194
#endif /* USE_REPL_SNPRINTF */
227195

228196
#if defined(WIN32)

‎src/interfaces/ecpg/compatlib/Makefile

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -47,7 +47,6 @@ submake-pgtypeslib:
4747
# Shared library stuff
4848
include $(top_srcdir)/src/Makefile.shlib
4949

50-
# XXX This library uses no symbols from snprintf.c.
5150
snprintf.c: % : $(top_srcdir)/src/port/%
5251
rm -f $@ && $(LN_S) $< .
5352

‎src/interfaces/ecpg/ecpglib/.gitignore

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,6 @@
55
/pgstrcasecmp.c
66
/snprintf.c
77
/strlcpy.c
8-
/syswrap.c
98
/thread.c
109
/win32setlocale.c
1110
/isinf.c

‎src/interfaces/ecpg/ecpglib/Makefile

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -25,7 +25,7 @@ override CFLAGS += $(PTHREAD_CFLAGS)
2525
LIBS := $(filter-out -lpgport, $(LIBS))
2626

2727
OBJS= execute.o typename.o descriptor.o sqlda.o data.o error.o prepare.o memory.o \
28-
connect.o misc.o path.o pgstrcasecmp.o syswrap.o \
28+
connect.o misc.o path.o pgstrcasecmp.o \
2929
$(filter snprintf.o strlcpy.o win32setlocale.o isinf.o, $(LIBOBJS))
3030

3131
# thread.c is needed only for non-WIN32 implementation of path.c
@@ -54,7 +54,7 @@ include $(top_srcdir)/src/Makefile.shlib
5454
# necessarily use the same object files as the backend uses. Instead,
5555
# symlink the source files in here and build our own object file.
5656

57-
path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c win32setlocale.c isinf.c: % : $(top_srcdir)/src/port/%
57+
path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c win32setlocale.c isinf.c: % : $(top_srcdir)/src/port/%
5858
rm -f $@ && $(LN_S) $< .
5959

6060
misc.o: misc.c $(top_builddir)/src/port/pg_config_paths.h
@@ -71,6 +71,6 @@ uninstall: uninstall-lib
7171

7272
clean distclean: clean-lib
7373
rm -f $(OBJS)
74-
rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c win32setlocale.c isinf.c
74+
rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c win32setlocale.c isinf.c
7575

7676
maintainer-clean: distclean maintainer-clean-lib

‎src/interfaces/ecpg/pgtypeslib/.gitignore

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,4 +4,3 @@
44
/pgstrcasecmp.c
55
/rint.c
66
/snprintf.c
7-
/syswrap.c

‎src/interfaces/ecpg/pgtypeslib/Makefile

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -29,7 +29,7 @@ SHLIB_LINK += -lm
2929
SHLIB_EXPORTS = exports.txt
3030

3131
OBJS= numeric.o datetime.o common.o dt_common.o timestamp.o interval.o \
32-
pgstrcasecmp.o syswrap.o \
32+
pgstrcasecmp.o \
3333
$(filter rint.o snprintf.o, $(LIBOBJS))
3434

3535
all: all-lib
@@ -42,7 +42,7 @@ include $(top_srcdir)/src/Makefile.shlib
4242
# necessarily use the same object files as the backend uses. Instead,
4343
# symlink the source files in here and build our own object file.
4444

45-
pgstrcasecmp.c rint.c snprintf.c syswrap.c: % : $(top_srcdir)/src/port/%
45+
pgstrcasecmp.c rint.c snprintf.c: % : $(top_srcdir)/src/port/%
4646
rm -f $@ && $(LN_S) $< .
4747

4848
install: all installdirs install-lib
@@ -52,6 +52,6 @@ installdirs: installdirs-lib
5252
uninstall: uninstall-lib
5353

5454
clean distclean: clean-lib
55-
rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c syswrap.c
55+
rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c
5656

5757
maintainer-clean: distclean maintainer-clean-lib

‎src/interfaces/libpq/.gitignore

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,6 @@
1313
/strerror.c
1414
/strlcpy.c
1515
/system.c
16-
/syswrap.c
1716
/thread.c
1817
/win32error.c
1918
/win32setlocale.c

‎src/interfaces/libpq/Makefile

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -36,7 +36,7 @@ OBJS= fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
3636
libpq-events.o
3737
# libpgport C files we always use
3838
OBJS += chklocale.o inet_net_ntop.o noblock.o pgstrcasecmp.o pqsignal.o \
39-
syswrap.o thread.o
39+
thread.o
4040
# libpgport C files that are needed if identified by configure
4141
OBJS += $(filter crypt.o getaddrinfo.o getpeereid.o inet_aton.o open.o system.o snprintf.o strerror.o strlcpy.o win32error.o win32setlocale.o, $(LIBOBJS))
4242
# backend/libpq
@@ -89,7 +89,7 @@ backend_src = $(top_srcdir)/src/backend
8989
# For some libpgport modules, this only happens if configure decides
9090
# the module is needed (see filter hack in OBJS, above).
9191

92-
chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c inet_net_ntop.c noblock.c open.c system.c pgsleep.c pgstrcasecmp.c pqsignal.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c win32error.c win32setlocale.c: % : $(top_srcdir)/src/port/%
92+
chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c inet_net_ntop.c noblock.c open.c system.c pgsleep.c pgstrcasecmp.c pqsignal.c snprintf.c strerror.c strlcpy.c thread.c win32error.c win32setlocale.c: % : $(top_srcdir)/src/port/%
9393
rm -f $@ && $(LN_S) $< .
9494

9595
ip.c md5.c: % : $(backend_src)/libpq/%
@@ -150,7 +150,7 @@ clean distclean: clean-lib
150150
# Might be left over from a Win32 client-only build
151151
rm -f pg_config_paths.h
152152
rm -f inet_net_ntop.c noblock.c pgstrcasecmp.c pqsignal.c thread.c
153-
rm -f chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c open.c system.c snprintf.c strerror.c strlcpy.c syswrap.c win32error.c win32setlocale.c
153+
rm -f chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c open.c system.c snprintf.c strerror.c strlcpy.c win32error.c win32setlocale.c
154154
rm -f pgsleep.c
155155
rm -f md5.c ip.c
156156
rm -f encnames.c wchar.c

‎src/interfaces/libpq/bcc32.mak

Lines changed: 0 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -107,7 +107,6 @@ CLEAN :
107107
-@erase "$(INTDIR)\pgsleep.obj"
108108
-@erase "$(INTDIR)\open.obj"
109109
-@erase "$(INTDIR)\system.obj"
110-
-@erase "$(INTDIR)\syswrap.obj"
111110
-@erase "$(INTDIR)\win32error.obj"
112111
-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
113112
-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -152,7 +151,6 @@ LIB32_OBJS= \
152151
"$(INTDIR)\pgsleep.obj" \
153152
"$(INTDIR)\open.obj" \
154153
"$(INTDIR)\system.obj" \
155-
"$(INTDIR)\syswrap.obj" \
156154
"$(INTDIR)\win32error.obj" \
157155
"$(INTDIR)\pthread-win32.obj"
158156

@@ -304,11 +302,6 @@ LINK32_FLAGS = -Gn -L$(BCB)\lib;$(INTDIR); -x -Tpd -v
304302
$(CPP_PROJ) /I"." ..\..\port\system.c
305303
<<
306304

307-
"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
308-
$(CPP) @<<
309-
$(CPP_PROJ) ..\..\port\syswrap.c
310-
<<
311-
312305
"$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
313306
$(CPP) @<<
314307
$(CPP_PROJ) /I"." ..\..\port\win32error.c

‎src/interfaces/libpq/win32.mak

Lines changed: 0 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -114,7 +114,6 @@ CLEAN :
114114
-@erase "$(INTDIR)\pgsleep.obj"
115115
-@erase "$(INTDIR)\open.obj"
116116
-@erase "$(INTDIR)\system.obj"
117-
-@erase "$(INTDIR)\syswrap.obj"
118117
-@erase "$(INTDIR)\win32error.obj"
119118
-@erase "$(INTDIR)\win32setlocale.obj"
120119
-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
@@ -162,7 +161,6 @@ LIB32_OBJS= \
162161
"$(INTDIR)\pgsleep.obj" \
163162
"$(INTDIR)\open.obj" \
164163
"$(INTDIR)\system.obj" \
165-
"$(INTDIR)\syswrap.obj" \
166164
"$(INTDIR)\win32error.obj" \
167165
"$(INTDIR)\win32setlocale.obj" \
168166
"$(INTDIR)\pthread-win32.obj"
@@ -344,11 +342,6 @@ LINK32_OBJS= \
344342
$(CPP_PROJ) /I"." ..\..\port\system.c
345343
<<
346344

347-
"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
348-
$(CPP) @<<
349-
$(CPP_PROJ) ..\..\port\syswrap.c
350-
<<
351-
352345
"$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
353346
$(CPP) @<<
354347
$(CPP_PROJ) /I"." ..\..\port\win32error.c

‎src/pl/plperl/plperl.h

Lines changed: 8 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -39,8 +39,10 @@
3939
* So we undefine them here and redefine them after it's done its dirty deed.
4040
*/
4141

42+
#ifdef USE_REPL_SNPRINTF
4243
#undef snprintf
4344
#undef vsnprintf
45+
#endif
4446

4547

4648
/* required for perl API */
@@ -49,19 +51,21 @@
4951
#include "XSUB.h"
5052

5153
/* put back our snprintf and vsnprintf */
54+
#ifdef USE_REPL_SNPRINTF
5255
#ifdef snprintf
5356
#undef snprintf
5457
#endif
5558
#ifdef vsnprintf
5659
#undef vsnprintf
5760
#endif
5861
#ifdef __GNUC__
59-
#define vsnprintf(...) vsnprintf_throw_on_fail(__VA_ARGS__)
60-
#define snprintf(...) snprintf_throw_on_fail(__VA_ARGS__)
62+
#define vsnprintf(...) pg_vsnprintf(__VA_ARGS__)
63+
#define snprintf(...) pg_snprintf(__VA_ARGS__)
6164
#else
62-
#define vsnprintf vsnprintf_throw_on_fail
63-
#define snprintf snprintf_throw_on_fail
65+
#define vsnprintf pg_vsnprintf
66+
#define snprintf pg_snprintf
6467
#endif /* __GNUC__ */
68+
#endif /* USE_REPL_SNPRINTF */
6569

6670
/* perl version and platform portability */
6771
#define NEED_eval_pv

‎src/pl/plpython/plpython.h

Lines changed: 8 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -35,8 +35,10 @@
3535
* So we undefine them here and redefine them after it's done its dirty deed.
3636
*/
3737

38+
#ifdef USE_REPL_SNPRINTF
3839
#undef snprintf
3940
#undef vsnprintf
41+
#endif
4042

4143
#if defined(_MSC_VER) && defined(_DEBUG)
4244
/* Python uses #pragma to bring in a non-default libpython on VC++ if
@@ -122,19 +124,21 @@ typedef int Py_ssize_t;
122124
#include <eval.h>
123125

124126
/* put back our snprintf and vsnprintf */
127+
#ifdef USE_REPL_SNPRINTF
125128
#ifdef snprintf
126129
#undef snprintf
127130
#endif
128131
#ifdef vsnprintf
129132
#undef vsnprintf
130133
#endif
131134
#ifdef __GNUC__
132-
#define vsnprintf(...) vsnprintf_throw_on_fail(__VA_ARGS__)
133-
#define snprintf(...) snprintf_throw_on_fail(__VA_ARGS__)
135+
#define vsnprintf(...) pg_vsnprintf(__VA_ARGS__)
136+
#define snprintf(...) pg_snprintf(__VA_ARGS__)
134137
#else
135-
#define vsnprintf vsnprintf_throw_on_fail
136-
#define snprintf snprintf_throw_on_fail
138+
#define vsnprintf pg_vsnprintf
139+
#define snprintf pg_snprintf
137140
#endif /* __GNUC__ */
141+
#endif /* USE_REPL_SNPRINTF */
138142

139143
/*
140144
* Used throughout, and also by the Python 2/3 porting layer, so it's easier to

‎src/port/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -33,7 +33,7 @@ LIBS += $(PTHREAD_LIBS)
3333
OBJS = $(LIBOBJS) chklocale.o erand48.o fls.o inet_net_ntop.o \
3434
noblock.o path.o pgcheckdir.o pg_crc.o pgmkdirp.o pgsleep.o \
3535
pgstrcasecmp.o pqsignal.o \
36-
qsort.o qsort_arg.o quotes.o sprompt.o syswrap.o tar.o thread.o
36+
qsort.o qsort_arg.o quotes.o sprompt.o tar.o thread.o
3737

3838
# foo_srv.o and foo.o are both built from foo.c, but only foo.o has -DFRONTEND
3939
OBJS_SRV = $(OBJS:%.o=%_srv.o)

‎src/port/snprintf.c

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -99,7 +99,6 @@
9999
/* Prevent recursion */
100100
#undef vsnprintf
101101
#undef snprintf
102-
#undef vsprintf
103102
#undef sprintf
104103
#undef vfprintf
105104
#undef fprintf
@@ -176,7 +175,7 @@ pg_snprintf(char *str, size_t count, const char *fmt,...)
176175
return len;
177176
}
178177

179-
int
178+
static int
180179
pg_vsprintf(char *str, const char *fmt, va_list args)
181180
{
182181
PrintfTarget target;

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