Re: Found a buffer-overflow defect in asynchronous database connection API PQconnectPoll

Further to this.

I tried a synchronous mode of connection, with the code below.

Even that produces the error report as below;

Sudheer

Source code

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "libpq-fe.h"

int main()
{
PGconn *p = NULL;
const char* keywords[] = { "host", "dbname", "user", "password", NULL };
const char* values[] = { "localhost", "AAA", "gen", "GEN", NULL };

p = PQconnectdbParams(keywords, values, 0);

if (p == NULL) {
printf("COULD NOT ALLOCATE MEMORY\n");
exit(1);
}
else if (PQstatus(p) == CONNECTION_BAD) {
printf("COULD NOT CONNECT\n");
PQfinish(p);
p = NULL;
}

return 0;
}

makefile

all: a b

b.o: b.c
cc -c -fsanitize="address" b.c -I/opt/local/include/postgresql13

a.o: a.c
cc -c -fsanitize="address" a.c -I/opt/local/include/postgresql13

a: a.o
cc -lpq -L/opt/local/lib/postgresql13/ -fsanitize="address" -o a a.o

b: b.o
cc -lpq -L/opt/local/lib/postgresql13/ -fsanitize="address" -o b b.o

clean:
rm -f a a.o b b.o

REPORT:

=================================================================
==62688==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6070000173d6 at pc 0x0001049d68f4 bp 0x7ffeeb2a38a0 sp 0x7ffeeb2a3060
READ of size 71 at 0x6070000173d6 thread T0
#0 0x1049d68f3 in wrap_strlen+0x183 (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x198f3)
#1 0x10498a7ea in dopr+0xe4 (libpq.5.dylib:x86_64+0x1c7ea)
#2 0x10498a6e2 in pg_vsnprintf+0x52 (libpq.5.dylib:x86_64+0x1c6e2)
#3 0x104982e91 in appendPQExpBufferVA+0x3e (libpq.5.dylib:x86_64+0x14e91)
#4 0x104982fae in appendPQExpBuffer+0xc4 (libpq.5.dylib:x86_64+0x14fae)
#5 0x104985b64 in pg_GSS_error_int+0x5b (libpq.5.dylib:x86_64+0x17b64)
#6 0x104985af3 in pg_GSS_error+0x66 (libpq.5.dylib:x86_64+0x17af3)
#7 0x1049864fe in pqsecure_open_gss+0x334 (libpq.5.dylib:x86_64+0x184fe)
#8 0x10497440d in PQconnectPoll+0xac9 (libpq.5.dylib:x86_64+0x640d)
#9 0x1049720f1 in connectDBComplete+0x11f (libpq.5.dylib:x86_64+0x40f1)
#10 0x104971c61 in PQconnectdbParams+0x23 (libpq.5.dylib:x86_64+0x3c61)
#11 0x10495da84 in main+0x3a4 (b:x86_64+0x100003a84)
#12 0x7fff20563f5c in start+0x0 (libdyld.dylib:x86_64+0x15f5c)

0x6070000173d6 is located 0 bytes to the right of 70-byte region [0x607000017390,0x6070000173d6)
allocated by thread T0 here:
#0 0x104a05460 in wrap_malloc+0xa0 (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x48460)
#1 0x7fff2d8f7396 in _gss_mg_get_error+0x96 (GSS:x86_64+0x9396)
#2 0x7fff2d8f71e6 in gss_display_status+0x176 (GSS:x86_64+0x91e6)
#3 0x104985b4b in pg_GSS_error_int+0x42 (libpq.5.dylib:x86_64+0x17b4b)
#4 0x104985af3 in pg_GSS_error+0x66 (libpq.5.dylib:x86_64+0x17af3)
#5 0x1049864fe in pqsecure_open_gss+0x334 (libpq.5.dylib:x86_64+0x184fe)
#6 0x10497440d in PQconnectPoll+0xac9 (libpq.5.dylib:x86_64+0x640d)
#7 0x1049720f1 in connectDBComplete+0x11f (libpq.5.dylib:x86_64+0x40f1)
#8 0x104971c61 in PQconnectdbParams+0x23 (libpq.5.dylib:x86_64+0x3c61)
#9 0x10495da84 in main+0x3a4 (b:x86_64+0x100003a84)
#10 0x7fff20563f5c in start+0x0 (libdyld.dylib:x86_64+0x15f5c)

SUMMARY: AddressSanitizer: heap-buffer-overflow (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x198f3) in wrap_strlen+0x183
Shadow bytes around the buggy address:
0x1c0e00002e20: fd fd fd fd fd fd fd fd fa fa fa fa fd fd fd fd
0x1c0e00002e30: fd fd fd fd fd fd fa fa fa fa fd fd fd fd fd fd
0x1c0e00002e40: fd fd fd fa fa fa fa fa fd fd fd fd fd fd fd fd
0x1c0e00002e50: fd fa fa fa fa fa fd fd fd fd fd fd fd fd fd fa
0x1c0e00002e60: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fa fa
=>0x1c0e00002e70: fa fa 00 00 00 00 00 00 00 00[06]fa fa fa fa fa
0x1c0e00002e80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00002e90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00002ea0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00002eb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00002ec0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==62688==ABORTING
Abort

> On 23-Jun-2021, at 5:43 PM, Sudheer H R <sudheer(dot)hr(at)tekenlight(dot)com> wrote:
>
> Hello,
>
> I am trying to integrate the client library libpq with a server that is developed based on libev model on a Macbook PRO - maxOS Big Sur OSX version 11.4
>
> While trying to sanitise the code for heap buffer overflows I compiled and linked the executable with clang -fsanitize=“address” option. The connection library indicates a buffer over flow in an internal source code of the module.
>
> In order to isolate the problem, I tried writing a separate simple program as listed below, which also gives the same error report upon running.
>
>
> Request you to please provide any guidance in this regard.
>
>
> I am using the Mac ports based installation of PostgreSQL version 13.2 (or 3)
>
>
> Any help in this regard is much appreciated
>
> Regards,
> Sudheer
>
>
>
> Source code:
>
>
> #include <unistd.h>
> #include "libpq-fe.h"
>
>
> int main()
> {
> PGconn *p = NULL;
> const char* keywords[] = { "host", "dbname", "user", "password", NULL };
> const char* values[] = { "localhost", "AAA", "gen", "GEN", NULL };
>
> p = PQconnectStartParams(keywords, values, 0);
>
> if (p == NULL) {
> printf("COULD NOT ALLOCATE MEMORY\n");
> exit(1);
> }
> else if (PQstatus(p) == CONNECTION_BAD) {
> printf("COULD NOT CONNECT\n");
> PQfinish(p);
> p = NULL;
> }
>
> PostgresPollingStatusType ps;
>
> ps = PQconnectPoll(p);
> while (ps != PGRES_POLLING_FAILED && ps != PGRES_POLLING_OK) {
> sleep(1);
> ps = PQconnectPoll(p);
> printf("open_connection_finalize[%d]\n", ps);
> }
>
> printf("DONE\n");
>
> return 0;
> }
>
>
>
>
>
> BUFFER OVERFLOW SANITIZER REPORT
>
>
> open_connection_finalize[1]
> =================================================================
> ==62203==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60700001abd6 at pc 0x0001098118f4 bp 0x7ffee646d910 sp 0x7ffee646d0d0
> READ of size 71 at 0x60700001abd6 thread T0
> #0 0x1098118f3 in wrap_strlen+0x183 (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x198f3)
> #1 0x1097c37ea in dopr+0xe4 (libpq.5.dylib:x86_64+0x1c7ea)
> #2 0x1097c36e2 in pg_vsnprintf+0x52 (libpq.5.dylib:x86_64+0x1c6e2)
> #3 0x1097bbe91 in appendPQExpBufferVA+0x3e (libpq.5.dylib:x86_64+0x14e91)
> #4 0x1097bbfae in appendPQExpBuffer+0xc4 (libpq.5.dylib:x86_64+0x14fae)
> #5 0x1097beb64 in pg_GSS_error_int+0x5b (libpq.5.dylib:x86_64+0x17b64)
> #6 0x1097beaf3 in pg_GSS_error+0x66 (libpq.5.dylib:x86_64+0x17af3)
> #7 0x1097bf4fe in pqsecure_open_gss+0x334 (libpq.5.dylib:x86_64+0x184fe)
> #8 0x1097ad40d in PQconnectPoll+0xac9 (libpq.5.dylib:x86_64+0x640d)
> #9 0x109793a2c in main+0x46c (a:x86_64+0x100003a2c)
> #10 0x7fff20563f5c in start+0x0 (libdyld.dylib:x86_64+0x15f5c)
>
> 0x60700001abd6 is located 0 bytes to the right of 70-byte region [0x60700001ab90,0x60700001abd6)
> allocated by thread T0 here:
> #0 0x109840460 in wrap_malloc+0xa0 (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x48460)
> #1 0x7fff2d8f7396 in _gss_mg_get_error+0x96 (GSS:x86_64+0x9396)
> #2 0x7fff2d8f71e6 in gss_display_status+0x176 (GSS:x86_64+0x91e6)
> #3 0x1097beb4b in pg_GSS_error_int+0x42 (libpq.5.dylib:x86_64+0x17b4b)
> #4 0x1097beaf3 in pg_GSS_error+0x66 (libpq.5.dylib:x86_64+0x17af3)
> #5 0x1097bf4fe in pqsecure_open_gss+0x334 (libpq.5.dylib:x86_64+0x184fe)
> #6 0x1097ad40d in PQconnectPoll+0xac9 (libpq.5.dylib:x86_64+0x640d)
> #7 0x109793a2c in main+0x46c (a:x86_64+0x100003a2c)
> #8 0x7fff20563f5c in start+0x0 (libdyld.dylib:x86_64+0x15f5c)
>
> SUMMARY: AddressSanitizer: heap-buffer-overflow (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x198f3) in wrap_strlen+0x183
> Shadow bytes around the buggy address:
> 0x1c0e00003520: fd fd fd fd fd fd fd fd fa fa fa fa fd fd fd fd
> 0x1c0e00003530: fd fd fd fd fd fd fa fa fa fa fd fd fd fd fd fd
> 0x1c0e00003540: fd fd fd fa fa fa fa fa fd fd fd fd fd fd fd fd
> 0x1c0e00003550: fd fa fa fa fa fa fd fd fd fd fd fd fd fd fd fa
> 0x1c0e00003560: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fa fa
> =>0x1c0e00003570: fa fa 00 00 00 00 00 00 00 00[06]fa fa fa fa fa
> 0x1c0e00003580: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x1c0e00003590: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x1c0e000035a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x1c0e000035b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x1c0e000035c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> Shadow byte legend (one shadow byte represents 8 application bytes):
> Addressable: 00
> Partially addressable: 01 02 03 04 05 06 07
> Heap left redzone: fa
> Freed heap region: fd
> Stack left redzone: f1
> Stack mid redzone: f2
> Stack right redzone: f3
> Stack after return: f5
> Stack use after scope: f8
> Global redzone: f9
> Global init order: f6
> Poisoned by user: f7
> Container overflow: fc
> Array cookie: ac
> Intra object redzone: bb
> ASan internal: fe
> Left alloca redzone: ca
> Right alloca redzone: cb
> Shadow gap: cc
> ==62203==ABORTING
> Abort
>
>