mirror of
https://github.com/tursodatabase/libsql.git
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215 lines
6.3 KiB
Tcl
215 lines
6.3 KiB
Tcl
#
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# Run this Tcl script to generate the audit.html file.
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#
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set rcsid {$Id: audit.tcl,v 1.1 2002/07/13 16:52:35 drh Exp $}
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puts {<html>
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<head>
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<title>SQLite Security Audit Procedure</title>
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</head>
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<body bgcolor=white>
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<h1 align=center>
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SQLite Security Audit Procedure
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</h1>}
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puts "<p align=center>
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(This page was last modified on [lrange $rcsid 3 4] UTC)
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</p>"
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puts {
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<p>
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A security audit for SQLite consists of two components. First, there is
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a check for common errors that often lead to security problems. Second,
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an attempt is made to construct a proof that SQLite has certain desirable
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security properties.
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</p>
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<h2>Part I: Things to check</h2>
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<p>
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Scan all source code and check for the following common errors:
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</p>
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<ol>
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<li><p>
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Verify that the destination buffer is large enough to hold its result
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in every call to the following routines:
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<ul>
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<li> <b>strcpy()</b> </li>
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<li> <b>strncpy()</b> </li>
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<li> <b>strcat()</b> </li>
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<li> <b>memcpy()</b> </li>
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<li> <b>memset()</b> </li>
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<li> <b>memmove()</b> </li>
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<li> <b>bcopy()</b> </li>
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<li> <b>sprintf()</b> </li>
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<li> <b>scanf()</b> </li>
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</ul>
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</p></li>
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<li><p>
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Verify that pointers returned by subroutines are not NULL before using
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the pointers. In particular, make sure the return values for the following
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routines are checked before they are used:
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<ul>
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<li> <b>malloc()</b> </li>
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<li> <b>realloc()</b> </li>
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<li> <b>sqliteMalloc()</b> </li>
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<li> <b>sqliteRealloc()</b> </li>
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<li> <b>sqliteStrDup()</b> </li>
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<li> <b>sqliteStrNDup()</b> </li>
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<li> <b>sqliteExpr()</b> </li>
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<li> <b>sqliteExprFunction()</b> </li>
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<li> <b>sqliteExprListAppend()</b> </li>
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<li> <b>sqliteResultSetOfSelect()</b> </li>
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<li> <b>sqliteIdListAppend()</b> </li>
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<li> <b>sqliteSrcListAppend()</b> </li>
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<li> <b>sqliteSelectNew()</b> </li>
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<li> <b>sqliteTableNameToTable()</b> </li>
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<li> <b>sqliteTableTokenToSrcList()</b> </li>
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<li> <b>sqliteWhereBegin()</b> </li>
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<li> <b>sqliteFindTable()</b> </li>
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<li> <b>sqliteFindIndex()</b> </li>
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<li> <b>sqliteTableNameFromToken()</b> </li>
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<li> <b>sqliteGetVdbe()</b> </li>
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<li> <b>sqlite_mprintf()</b> </li>
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<li> <b>sqliteExprDup()</b> </li>
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<li> <b>sqliteExprListDup()</b> </li>
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<li> <b>sqliteSrcListDup()</b> </li>
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<li> <b>sqliteIdListDup()</b> </li>
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<li> <b>sqliteSelectDup()</b> </li>
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<li> <b>sqliteFindFunction()</b> </li>
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<li> <b>sqliteTriggerSelectStep()</b> </li>
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<li> <b>sqliteTriggerInsertStep()</b> </li>
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<li> <b>sqliteTriggerUpdateStep()</b> </li>
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<li> <b>sqliteTriggerDeleteStep()</b> </li>
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</ul>
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</p></li>
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<li><p>
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On all functions and procedures, verify that pointer parameters are not NULL
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before dereferencing those parameters.
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</p></li>
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<li><p>
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Check to make sure that temporary files are opened safely: that the process
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will not overwrite an existing file when opening the temp file and that
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another process is unable to substitute a file for the temp file being
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opened.
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</p></li>
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</ol>
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<h2>Part II: Things to prove</h2>
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<p>
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Prove that SQLite exhibits the characteristics outlined below:
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</p>
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<ol>
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<li><p>
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The following are preconditions:</p>
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<p><ul>
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<li><b>Z</b> is an arbitrary-length NUL-terminated string.</li>
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<li>An existing SQLite database has been opened. The return value
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from the call to <b>sqlite_open()</b> is stored in the variable
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<b>db</b>.</li>
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<li>The database contains at least one table of the form:
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<blockquote><pre>
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CREATE TABLE t1(a CLOB);
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</pre></blockquote></li>
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<li>There are no user-defined functions other than the standard
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build-in functions.</li>
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</ul></p>
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<p>The following statement of C code is executed:</p>
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<blockquote><pre>
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sqlite_exec_printf(
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db,
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"INSERT INTO t1(a) VALUES('%q');",
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0, 0, 0, Z
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);
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</pre></blockquote>
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<p>Prove the following are true for all possible values of string <b>Z</b>:</p>
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<ol type="a">
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<li><p>
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The call to <b>sqlite_exec_printf()</b> will
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return in a length of time that is a polynomial in <b>strlen(Z)</b>.
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It might return an error code but it will not crash.
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</p></li>
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<li><p>
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At most one new row will be inserted into table t1.
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</p></li>
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<li><p>
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No preexisting rows of t1 will be deleted or modified.
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</p></li>
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<li><p>
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No tables other than t1 will be altered in any way.
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</p></li>
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<li><p>
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No preexisting files on the host computers filesystem, other than
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the database file itself, will be deleted or modified.
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</p></li>
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<li><p>
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For some constants <b>K1</b> and <b>K2</b>,
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if at least <b>K1*strlen(Z) + K2</b> bytes of contiguous memory are
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available to <b>malloc()</b>, then the call to <b>sqlite_exec_printf()</b>
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will not return SQLITE_NOMEM.
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</p></li>
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</ol>
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</p></li>
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<li><p>
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The following are preconditions:
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<p><ul>
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<li><b>Z</b> is an arbitrary-length NUL-terminated string.</li>
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<li>An existing SQLite database has been opened. The return value
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from the call to <b>sqlite_open()</b> is stored in the variable
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<b>db</b>.</li>
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<li>There exists a callback function <b>cb()</b> that appends all
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information passed in through its parameters into a single
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data buffer called <b>Y</b>.</li>
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<li>There are no user-defined functions other than the standard
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build-in functions.</li>
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</ul></p>
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<p>The following statement of C code is executed:</p>
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<blockquote><pre>
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sqlite_exec(db, Z, cb, 0, 0);
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</pre></blockquote>
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<p>Prove the following are true for all possible values of string <b>Z</b>:</p>
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<ol type="a">
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<li><p>
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The call to <b>sqlite_exec()</b> will
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return in a length of time which is a polynomial in <b>strlen(Z)</b>.
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It might return an error code but it will not crash.
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</p></li>
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<li><p>
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After <b>sqlite_exec()</b> returns, the buffer <b>Y</b> will not contain
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any content from any preexisting file on the host computers file system,
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except for the database file.
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</p></li>
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<li><p>
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After the call to <b>sqlite_exec()</b> returns, the database file will
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still be well-formed. It might not contain the same data, but it will
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still be a properly constructed SQLite database file.
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</p></li>
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<li><p>
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No preexisting files on the host computers filesystem, other than
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the database file itself, will be deleted or modified.
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</p></li>
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<li><p>
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For some constants <b>K1</b> and <b>K2</b>,
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if at least <b>K1*strlen(Z) + K2</b> bytes of contiguous memory are
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available to <b>malloc()</b>, then the call to <b>sqlite_exec()</b>
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will not return SQLITE_NOMEM.
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</p></li>
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</ol>
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</p></li>
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</ol>
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}
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puts {
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<p><hr /></p>
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<p><a href="index.html"><img src="/goback.jpg" border=0 />
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Back to the SQLite Home Page</a>
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</p>
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</body></html>}
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