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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
1 parent 59cc2f5 commit cf89353

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14 files changed

+37
-243
lines changed

14 files changed

+37
-243
lines changed

‎src/include/port.h

Lines changed: 25 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -148,21 +148,19 @@ extern int pg_strncasecmp(const char *s1, const char *s2, size_t n);
148148
extern unsigned char pg_toupper(unsigned char ch);
149149
extern unsigned char pg_tolower(unsigned char ch);
150150

151+
#ifdef USE_REPL_SNPRINTF
152+
151153
/*
152-
* Capture macro-compatible calls to printf() and friends, and redirect them
153-
* to wrappers that throw errors in lieu of reporting failure in a return
154-
* value. Versions of libintl >= 0.13 similarly redirect to versions that
155-
* understand the %$ format, so disable libintl macros first.
154+
* Versions of libintl >= 0.13 try to replace printf() and friends with
155+
* macros to their own versions that understand the %$ format. We do the
156+
* same, so disable their macros, if they exist.
156157
*/
157158
#ifdef vsnprintf
158159
#undef vsnprintf
159160
#endif
160161
#ifdef snprintf
161162
#undef snprintf
162163
#endif
163-
#ifdef vsprintf
164-
#undef vsprintf
165-
#endif
166164
#ifdef sprintf
167165
#undef sprintf
168166
#endif
@@ -176,61 +174,11 @@ extern unsigned char pg_tolower(unsigned char ch);
176174
#undef printf
177175
#endif
178176

179-
extern int
180-
vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
181-
__attribute__((format(printf, 3, 0)));
182-
extern int
183-
snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
184-
__attribute__((format(printf, 3, 4)));
185-
extern int
186-
vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
187-
__attribute__((format(printf, 2, 0)));
188-
extern int
189-
sprintf_throw_on_fail(char *str, const char *fmt,...)
190-
__attribute__((format(printf, 2, 3)));
191-
extern int
192-
vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
193-
__attribute__((format(printf, 2, 0)));
194-
extern int
195-
fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
196-
__attribute__((format(printf, 2, 3)));
197-
extern int
198-
printf_throw_on_fail(const char *fmt,...)
199-
__attribute__((format(printf, 1, 2)));
200-
201-
/*
202-
* The GCC-specific code below prevents the __attribute__(... 'printf')
203-
* above from being replaced, and this is required because gcc doesn't
204-
* know anything about printf_throw_on_fail.
205-
*/
206-
#ifdef __GNUC__
207-
#define vsnprintf(...) vsnprintf_throw_on_fail(__VA_ARGS__)
208-
#define snprintf(...) snprintf_throw_on_fail(__VA_ARGS__)
209-
#define vsprintf(...) vsprintf_throw_on_fail(__VA_ARGS__)
210-
#define sprintf(...) sprintf_throw_on_fail(__VA_ARGS__)
211-
#define vfprintf(...) vfprintf_throw_on_fail(__VA_ARGS__)
212-
#define fprintf(...) fprintf_throw_on_fail(__VA_ARGS__)
213-
#define printf(...) printf_throw_on_fail(__VA_ARGS__)
214-
#else
215-
#define vsnprintf vsnprintf_throw_on_fail
216-
#define snprintf snprintf_throw_on_fail
217-
#define vsprintf vsprintf_throw_on_fail
218-
#define sprintf sprintf_throw_on_fail
219-
#define vfprintf vfprintf_throw_on_fail
220-
#define fprintf fprintf_throw_on_fail
221-
#define printf printf_throw_on_fail
222-
#endif
223-
224-
#ifdef USE_REPL_SNPRINTF
225-
226-
/* Code outside syswrap.c should not call these. */
227-
228177
extern int pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args);
229178
extern int
230179
pg_snprintf(char *str, size_t count, const char *fmt,...)
231180
/* This extension allows gcc to check the format string */
232181
__attribute__((format(printf, 3, 4)));
233-
extern int pg_vsprintf(char *str, const char *fmt, va_list args);
234182
extern int
235183
pg_sprintf(char *str, const char *fmt,...)
236184
/* This extension allows gcc to check the format string */
@@ -245,6 +193,26 @@ pg_printf(const char *fmt,...)
245193
/* This extension allows gcc to check the format string */
246194
__attribute__((format(printf, 1, 2)));
247195

196+
/*
197+
* The GCC-specific code below prevents the __attribute__(... 'printf')
198+
* above from being replaced, and this is required because gcc doesn't
199+
* know anything about pg_printf.
200+
*/
201+
#ifdef __GNUC__
202+
#define vsnprintf(...) pg_vsnprintf(__VA_ARGS__)
203+
#define snprintf(...) pg_snprintf(__VA_ARGS__)
204+
#define sprintf(...) pg_sprintf(__VA_ARGS__)
205+
#define vfprintf(...) pg_vfprintf(__VA_ARGS__)
206+
#define fprintf(...) pg_fprintf(__VA_ARGS__)
207+
#define printf(...) pg_printf(__VA_ARGS__)
208+
#else
209+
#define vsnprintf pg_vsnprintf
210+
#define snprintf pg_snprintf
211+
#define sprintf pg_sprintf
212+
#define vfprintf pg_vfprintf
213+
#define fprintf pg_fprintf
214+
#define printf pg_printf
215+
#endif
248216
#endif /* USE_REPL_SNPRINTF */
249217

250218
/*

‎src/interfaces/ecpg/compatlib/Makefile

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -36,7 +36,6 @@ all: all-lib
3636
# Shared library stuff
3737
include $(top_srcdir)/src/Makefile.shlib
3838

39-
# XXX This library uses no symbols from snprintf.c.
4039
snprintf.c: % : $(top_srcdir)/src/port/%
4140
rm -f $@ && $(LN_S) $< .
4241

‎src/interfaces/ecpg/ecpglib/.gitignore

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,5 +6,4 @@
66
/path.c
77
/pgstrcasecmp.c
88
/strlcpy.c
9-
/syswrap.c
109
/thread.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 isinf.o, $(LIBOBJS))
3030

3131
# thread.c is needed only for non-WIN32 implementation of path.c
@@ -58,7 +58,7 @@ include $(top_srcdir)/src/Makefile.shlib
5858
# necessarily use the same object files as the backend uses. Instead,
5959
# symlink the source files in here and build our own object file.
6060

61-
path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
61+
path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
6262
rm -f $@ && $(LN_S) $< .
6363

6464
misc.o: misc.c $(top_builddir)/src/port/pg_config_paths.h
@@ -75,6 +75,6 @@ uninstall: uninstall-lib
7575

7676
clean distclean: clean-lib
7777
rm -f $(OBJS)
78-
rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c
78+
rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c
7979

8080
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
/exports.list
55

66
/pgstrcasecmp.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
@@ -8,7 +8,6 @@
88
/snprintf.c
99
/strerror.c
1010
/strlcpy.c
11-
/syswrap.c
1211
/thread.c
1312
/win32error.c
1413
/pgsleep.c

‎src/interfaces/libpq/Makefile

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -33,7 +33,7 @@ LIBS := $(LIBS:-lpgport=)
3333
OBJS= fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
3434
fe-protocol2.o fe-protocol3.o pqexpbuffer.o pqsignal.o fe-secure.o \
3535
libpq-events.o \
36-
md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o syswrap.o thread.o \
36+
md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o thread.o \
3737
$(filter crypt.o getaddrinfo.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o, $(LIBOBJS))
3838

3939
ifeq ($(PORTNAME), cygwin)
@@ -80,7 +80,7 @@ backend_src = $(top_srcdir)/src/backend
8080
# For port modules, this only happens if configure decides the module
8181
# is needed (see filter hack in OBJS, above).
8282

83-
crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
83+
crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
8484
rm -f $@ && $(LN_S) $< .
8585

8686
md5.c ip.c: % : $(backend_src)/libpq/%
@@ -133,7 +133,7 @@ ifneq (,$(findstring $(PORTNAME), win32 cygwin))
133133
endif
134134

135135
clean distclean: clean-lib
136-
rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
136+
rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
137137
# Might be left over from a Win32 client-only build
138138
rm -f pg_config_paths.h
139139

‎src/interfaces/libpq/bcc32.mak

Lines changed: 0 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -104,7 +104,6 @@ CLEAN :
104104
-@erase "$(INTDIR)\dirmod.obj"
105105
-@erase "$(INTDIR)\pgsleep.obj"
106106
-@erase "$(INTDIR)\open.obj"
107-
-@erase "$(INTDIR)\syswrap.obj"
108107
-@erase "$(INTDIR)\win32error.obj"
109108
-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
110109
-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -146,7 +145,6 @@ LIB32_OBJS= \
146145
"$(INTDIR)\dirmod.obj" \
147146
"$(INTDIR)\pgsleep.obj" \
148147
"$(INTDIR)\open.obj" \
149-
"$(INTDIR)\syswrap.obj" \
150148
"$(INTDIR)\win32error.obj" \
151149
"$(INTDIR)\pthread-win32.obj"
152150

@@ -275,11 +273,6 @@ LINK32_FLAGS = -Gn -L$(BCB)\lib;$(INTDIR); -x -Tpd -v
275273
$(CPP_PROJ) /I"." ..\..\port\open.c
276274
<<
277275

278-
"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
279-
$(CPP) @<<
280-
$(CPP_PROJ) ..\..\port\syswrap.c
281-
<<
282-
283276
"$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
284277
$(CPP) @<<
285278
$(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
@@ -111,7 +111,6 @@ CLEAN :
111111
-@erase "$(INTDIR)\dirmod.obj"
112112
-@erase "$(INTDIR)\pgsleep.obj"
113113
-@erase "$(INTDIR)\open.obj"
114-
-@erase "$(INTDIR)\syswrap.obj"
115114
-@erase "$(INTDIR)\win32error.obj"
116115
-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
117116
-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -155,7 +154,6 @@ LIB32_OBJS= \
155154
"$(INTDIR)\dirmod.obj" \
156155
"$(INTDIR)\pgsleep.obj" \
157156
"$(INTDIR)\open.obj" \
158-
"$(INTDIR)\syswrap.obj" \
159157
"$(INTDIR)\win32error.obj" \
160158
"$(INTDIR)\pthread-win32.obj"
161159

@@ -313,11 +311,6 @@ LINK32_OBJS= \
313311
$(CPP_PROJ) /I"." ..\..\port\open.c
314312
<<
315313

316-
"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
317-
$(CPP) @<<
318-
$(CPP_PROJ) ..\..\port\syswrap.c
319-
<<
320-
321314
"$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
322315
$(CPP) @<<
323316
$(CPP_PROJ) /I"." ..\..\port\win32error.c

‎src/port/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -31,7 +31,7 @@ override CPPFLAGS := -I$(top_builddir)/src/port -DFRONTEND $(CPPFLAGS)
3131
LIBS += $(PTHREAD_LIBS)
3232

3333
OBJS = $(LIBOBJS) chklocale.o dirmod.o exec.o noblock.o path.o \
34-
pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o syswrap.o thread.o
34+
pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o thread.o
3535
ifneq (,$(filter $(PORTNAME),cygwin win32))
3636
OBJS += pipe.o
3737
endif

‎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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