Correct some code in pg_restore when reading the header of a tar archive:

(1) The code doesn't initialize `sum', so the initial "does the checksum
    match?" test is wrong.

(2) The loop that is intended to check for a "null block" just checks
    the first byte of the tar block 512 times, rather than each of the
    512 bytes one time (!), which I'm guessing was the intent.

It was only through sheer luck that this worked in the first place.

Per Coverity static analysis performed by EnterpriseDB.
This commit is contained in:
Neil Conway 2005-06-22 02:00:47 +00:00
parent 06ecacded6
commit 05db8b501b

View File

@ -16,7 +16,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_backup_tar.c,v 1.47 2005/01/25 22:44:31 tgl Exp $
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_backup_tar.c,v 1.48 2005/06/22 02:00:47 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -1155,7 +1155,6 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
size_t len;
unsigned long ullen;
off_t hPos;
int i;
bool gotBlock = false;
while (!gotBlock)
@ -1178,7 +1177,7 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
hPos = ctx->tarFHpos;
/* Read a 512 byte block, return EOF, exit if short */
len = _tarReadRaw(AH, &h[0], 512, NULL, ctx->tarFH);
len = _tarReadRaw(AH, h, 512, NULL, ctx->tarFH);
if (len == 0) /* EOF */
return 0;
@ -1188,20 +1187,22 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
(unsigned long) len);
/* Calc checksum */
chk = _tarChecksum(&h[0]);
chk = _tarChecksum(h);
sscanf(&h[148], "%8o", &sum);
/*
* If the checksum failed, see if it is a null block. If so, then
* just try with next block...
* If the checksum failed, see if it is a null block. If so,
* silently continue to the next block.
*/
if (chk == sum)
gotBlock = true;
else
{
int i;
for (i = 0; i < 512; i++)
{
if (h[0] != 0)
if (h[i] != 0)
{
gotBlock = true;
break;
@ -1213,7 +1214,6 @@ _tarGetHeader(ArchiveHandle *AH, TAR_MEMBER *th)
sscanf(&h[0], "%99s", tag);
sscanf(&h[124], "%12lo", &ullen);
len = (size_t) ullen;
sscanf(&h[148], "%8o", &sum);
{
char buf[100];