Fix a crash that could occur if sqlite3_deserialize() was used to overwrite a database with an open transaction on it. Bug introduced by [fc42d31d6fca21ab] on 2018-03-07 and first released in version 3.23.0. This is not a vulnerability as an attacker that can exploit this already has the ability to execute arbitrary code. Forum post [forum:39134ba029 | 39134ba029].

FossilOrigin-Name: b7b0745d6def6b141c900884cd97f10f3afedcbfb4bd9ce2409ee2380a8602dd

manifest

@@ -1,5 +1,5 @@
-C Feature\sdetection\sfix\sfor\suint128\son\sRISCV\s32-bit.
-D 2026-04-27T12:25:36.307
+C Fix\sa\scrash\sthat\scould\soccur\sif\ssqlite3_deserialize()\swas\sused\sto\soverwrite\sa\sdatabase\swith\san\sopen\stransaction\son\sit.\sBug\sintroduced\sby\s[fc42d31d6fca21ab]\son\s2018-03-07\sand\sfirst\sreleased\sin\sversion\s3.23.0.\sThis\sis\snot\sa\svulnerability\sas\san\sattacker\sthat\scan\sexploit\sthis\salready\shas\sthe\sability\sto\sexecute\sarbitrary\scode.\sForum\spost\s[forum:39134ba029\s|\s39134ba029].
+D 2026-04-27T12:28:23.589
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -669,7 +669,7 @@ F sqlite3.1 1b9c24374a85dfc7eb8fa7c4266ee0db4f9609cceecfc5481cd8307e5af04366
 F sqlite3.pc.in e6dee284fba59ef500092fdc1843df3be8433323a3733c91da96690a50a5b398
 F src/alter.c 7d7ddbdc189f0e0c686e32ee170abdddc95c11f2089e40df4ffcee88f5334826
 F src/analyze.c 03bcfc083fc0cccaa9ded93604e1d4244ea245c17285d463ef6a60425fcb247d
-F src/attach.c 7cf07d4fa42b9fc8662237c60c40b730326c30aa90ae5fffc0b18b2d726ebf61
+F src/attach.c c58278c7d2d954785591c4fde81669ec3e4d52f348c453b028a19ae8adf4f338
 F src/auth.c ebec42df26b34a62b6750d30d9c2c03554a1c522020182476f7729a439fef04f
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c e242d4496774dfc88fa278177dd23b607dce369ccafb3f61b41638eea2c9b399
@@ -705,7 +705,7 @@ F src/mem1.c 3bb59158c38e05f6270e761a9f435bf19827a264c13d1631c58b84bdc96d73b2
 F src/mem2.c c8bfc9446fd0798bddd495eb5d9dbafa7d4b7287d8c22d50a83ac9daa26d8a75
 F src/mem3.c 30301196cace2a085cbedee1326a49f4b26deff0af68774ca82c1f7c06fda4f6
 F src/mem5.c b7da5c10a726aacacc9ad7cdcb0667deec643e117591cc69cf9b4b9e7f3e96ff
-F src/memdb.c a3feb427cdd4036ea2db0ba56d152f14c8212ca760ccb05fb7aa49ff6b897df3
+F src/memdb.c 0a0e827311cec57fdea2ed3142d6684704a1b90e7995b286f74fd7d1a6c5a62c
 F src/memjournal.c c283c6c95d940eb9dc70f1863eef3ee40382dbd35e5a1108026e7817c206e8a0
 F src/msvc.h 80b35f95d93bf996ccb3e498535255f2ef1118c78764719a7cd15ab4106ccac9
 F src/mutex.c 00b8cee206a67fd764d001f3a148494331d8d0b3b9c3974ecd69ff29bb444462
@@ -1420,7 +1420,7 @@ F test/malloctraceviewer.tcl 3e3ddf11e30d2b20f53aa16aa6615082fb24a100bea61cca721
 F test/manydb.test 28385ae2087967aa05c38624cec7d96ec74feb3e
 F test/mem5.test c6460fba403c5703141348cd90de1c294188c68f
 F test/memdb.test c1f2a343ad14398d5d6debda6ea33e80d0dafcc7
-F test/memdb1.test c737ac9aa5895092332b1dde24fae7ae494b7fcbcd346d22d600891096a3836d
+F test/memdb1.test 916093ae5ad097660a742890a9986d1f217a620ac95efb64884041ee4c408603
 F test/memdb2.test 4ba1fc09e2f51df80d148a540e4a3fa66d0462e91167b27497084de4d1f6b5b4
 F test/memjournal.test 70f3a00c7f84ee2978ad14e831231caa1e7f23915a2c54b4f775a021d5740c6c
 F test/memjournal2.test dbc2c5cb5f7b38950f4f6dc3e73fcecf0fcbed3fc32c7ce913bba164d288da1e
@@ -2197,10 +2197,9 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 4eeb1f74f61589f115810bd2a6876dcec9e674a2baf686f3b5b25678695aa797
-Q +362ef7bc00eea180fb3458bd8887021aed54e321901483edc00ad6b23a33d8e5
-Q +c4a2c20839ef75534d71d928a03ad276bdc488b0baa76c1505f48dc1ff0bcdd1
-R 11b0718bf8c5d4b4aed3fc95424c9319
+P e3f318bf52932460890333c6dcae352ab4b0c943d7be67734649eff1ff9fc9fc
+Q +77662cce9aa452ba5820e5f1a864a802763bd83b937cdb16e7025219eff7bd08
+R 13f45488f2adbf7d8419fcbad47e0b59
 U drh
-Z 837425dfa4a2d43d75765c2c159934d0
+Z 52f7987a045aaf068eaa89a2ec557d9d
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-e3f318bf52932460890333c6dcae352ab4b0c943d7be67734649eff1ff9fc9fc
+b7b0745d6def6b141c900884cd97f10f3afedcbfb4bd9ce2409ee2380a8602dd

src/attach.c

@@ -106,6 +106,16 @@ static void attachFunc(
     ** from sqlite3_deserialize() to close database db->init.iDb and
     ** reopen it as a MemDB */
     Btree *pNewBt = 0;
+
+    pNew = &db->aDb[db->init.iDb];
+    assert( pNew->pBt!=0 );
+    if( sqlite3BtreeTxnState(pNew->pBt)!=SQLITE_TXN_NONE
+     || sqlite3BtreeIsInBackup(pNew->pBt)
+    ){
+      rc = SQLITE_BUSY;
+      goto attach_error;
+    }
+
     pVfs = sqlite3_vfs_find("memdb");
     if( pVfs==0 ) return;
     rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB);
@@ -115,8 +125,7 @@ static void attachFunc(
         /* Both the Btree and the new Schema were allocated successfully.
         ** Close the old db and update the aDb[] slot with the new memdb
         ** values.  */
-        pNew = &db->aDb[db->init.iDb];
-        if( ALWAYS(pNew->pBt) ) sqlite3BtreeClose(pNew->pBt);
+        sqlite3BtreeClose(pNew->pBt);
         pNew->pBt = pNewBt;
         pNew->pSchema = pNewSchema;
       }else{

src/memdb.c

@@ -876,10 +876,10 @@ int sqlite3_deserialize(
   if( rc ) goto end_deserialize;
   db->init.iDb = (u8)iDb;
   db->init.reopenMemdb = 1;
-  rc = sqlite3_step(pStmt);
+  sqlite3_step(pStmt);
   db->init.reopenMemdb = 0;
-  if( rc!=SQLITE_DONE ){
-    rc = SQLITE_ERROR;
+  rc = sqlite3_finalize(pStmt);
+  if( rc!=SQLITE_OK ){
     goto end_deserialize;
   }
   p = memdbFromDbSchema(db, zSchema);
@@ -900,7 +900,6 @@ int sqlite3_deserialize(
   }
 
 end_deserialize:
-  sqlite3_finalize(pStmt);
   if( pData && (mFlags & SQLITE_DESERIALIZE_FREEONCLOSE)!=0 ){
     sqlite3_free(pData);
   }

test/memdb1.test

@@ -280,4 +280,41 @@ do_test 900 {
 } 1
 dbempty close
 
+
+#-------------------------------------------------------------------------
+# Make sure a database cannot be overwritten by deserialize() if 
+# there is an open transaction on it. 
+#
+do_execsql_test 1000 {
+  CREATE TABLE t(x); 
+  INSERT INTO t VALUES(1),(2);
+}
+
+set blob [db serialize main]
+
+do_test 1010 {
+  set seen 0
+  list [catch {
+    db eval {SELECT x FROM t} {
+      incr seen
+      if {$seen == 1} {
+        db deserialize main $blob
+      }
+    }
+  } msg] $msg
+} {1 {unable to set MEMDB content}}
+
+forcedelete test.db2
+sqlite3 db2 test.db2
+do_test 1020 {
+  set seen 0
+  sqlite3_backup B db2 main db main
+  B step 2
+  set res [list [catch {
+    db deserialize main $blob
+  } msg] $msg]
+  B finish
+  set res
+} {1 {unable to set MEMDB content}}
+
 finish_test