Harden code that processes Fossil Deltas against OOM and maliciously

malformed delta blobs. [bugs:/info/2026-06-10T07:01:00Z|Bug 2026-06-10T07:01:00Z] and [bugs:/info/2026-06-10T07:06:43Z|Bug 2026-06-10T07:06:43Z]. FossilOrigin-Name: 67271c31292bc1bddbb5e144c881c85c9f91b3963a1db4bae1f738adab50f7c0
2026-10-28 10:57:26 +03:00 · 2026-06-10 09:51:33 +00:00
parent 2cb57d9d4a
commit 84ead09d94
5 changed files with 57 additions and 31 deletions
--- a/ext/misc/fossildelta.c
+++ b/ext/misc/fossildelta.c
@@ -179,16 +179,26 @@ static unsigned int deltaGetInt(const char **pz, int *pLen){
    25, 26, 27, 28, 29, 30, 31, 32,   33, 34, 35, -1, -1, -1, -1, 36,
    -1, 37, 38, 39, 40, 41, 42, 43,   44, 45, 46, 47, 48, 49, 50, 51,
    52, 53, 54, 55, 56, 57, 58, 59,   60, 61, 62, -1, -1, -1, 63, -1,
+
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
  };
  unsigned int v = 0;
  int c;
  unsigned char *z = (unsigned char*)*pz;
-  unsigned char *zStart = z;
-  while( (c = zValue[0x7f&*(z++)])>=0 ){
-     v = (v<<6) + c;
+  unsigned char *zEnd = z + (*pLen);
+  while( z<zEnd && (c = zValue[*z])>=0 ){
+    v = (v<<6) + c;
+    z++;
  }
-  z--;
-  *pLen -= z - zStart;
+
+  *pLen -= (int)(z - (unsigned char*)*pz);
  *pz = (char*)z;
  return v;
 }
@@ -278,7 +288,8 @@ static unsigned int checksum(const char *zIn, size_t N){
 ** The delta string will be NUL-terminated, but it might also contain
 ** embedded NUL characters if either the zSrc or zOut files are
 ** binary.  This function returns the length of the delta string
-** in bytes, excluding the final NUL terminator character.
+** in bytes, excluding the final NUL terminator character.  It returns
+** 0 if an OOM occurs.
 **
 ** Output Format:
 **
@@ -370,6 +381,7 @@ static int delta_create(
  */
  nHash = lenSrc/NHASH;
  collide = sqlite3_malloc64( (sqlite3_int64)nHash*2*sizeof(int) );
+  if( collide==0 ) return 0;
  memset(collide, -1, nHash*2*sizeof(int));
  landmark = &collide[nHash];
  for(i=0; i<lenSrc-NHASH; i+=NHASH){
@@ -520,7 +532,7 @@ static int delta_create(
 static int delta_output_size(const char *zDelta, int lenDelta){
  int size;
  size = deltaGetInt(&zDelta, &lenDelta);
-  if( *zDelta!='\n' ){
+  if( lenDelta<=0 || *zDelta!='\n' ){
    /* ERROR: size integer not terminated by "\n" */
    return -1;
  }
@@ -562,7 +574,7 @@ static int delta_apply(
 #endif

  limit = deltaGetInt(&zDelta, &lenDelta);
-  if( *zDelta!='\n' ){
+  if( lenDelta<=0 || *zDelta!='\n' ){
    /* ERROR: size integer not terminated by "\n" */
    return -1;
  }
@@ -570,6 +582,7 @@ static int delta_apply(
  while( *zDelta && lenDelta>0 ){
    unsigned int cnt, ofst;
    cnt = deltaGetInt(&zDelta, &lenDelta);
+    if( lenDelta<=0 ) return -1;
    switch( zDelta[0] ){
      case '@': {
        zDelta++; lenDelta--;
@@ -889,7 +902,7 @@ static int deltaparsevtabNext(sqlite3_vtab_cursor *cur){
  }
  z = pCur->aDelta + pCur->iCursor;
  pCur->a1 = deltaGetInt(&z, &i);
-  switch( z[0] ){
+  switch( i>0 ? z[0] : 0 ){
    case '@': {
      z++;
      if( pCur->iNext>=pCur->nDelta ){
@@ -1019,7 +1032,7 @@ static int deltaparsevtabFilter(
  a = pCur->aDelta;
  pCur->eOp = DELTAPARSE_OP_SIZE;
  pCur->a1 = deltaGetInt(&a, &i);
-  if( a[0]!='\n' ){
+  if( i<=0 || a[0]!='\n' ){
    pCur->eOp = DELTAPARSE_OP_ERROR;
    pCur->a1 = pCur->a2 = 0;
    pCur->iNext = pCur->nDelta;
--- a/ext/rbu/sqlite3rbu.c
+++ b/ext/rbu/sqlite3rbu.c
@@ -516,16 +516,26 @@ static unsigned int rbuDeltaGetInt(const char **pz, int *pLen){
    25, 26, 27, 28, 29, 30, 31, 32,   33, 34, 35, -1, -1, -1, -1, 36,
    -1, 37, 38, 39, 40, 41, 42, 43,   44, 45, 46, 47, 48, 49, 50, 51,
    52, 53, 54, 55, 56, 57, 58, 59,   60, 61, 62, -1, -1, -1, 63, -1,
+
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
+    -1, -1, -1, -1, -1, -1, -1, -1,   -1, -1, -1, -1, -1, -1, -1, -1,
  };
  unsigned int v = 0;
  int c;
  unsigned char *z = (unsigned char*)*pz;
-  unsigned char *zStart = z;
-  while( (c = zValue[0x7f&*(z++)])>=0 ){
-     v = (v<<6) + c;
+  unsigned char *zEnd = z + (*pLen);
+  while( z<zEnd && (c = zValue[*z])>=0 ){
+    v = (v<<6) + c;
+    z++;
  }
-  z--;
-  *pLen -= (int)(z - zStart);
+
+  *pLen -= (int)(z - (unsigned char*)*pz);
  *pz = (char*)z;
  return v;
 }
@@ -601,7 +611,7 @@ static int rbuDeltaApply(
 #endif

  limit = rbuDeltaGetInt(&zDelta, &lenDelta);
-  if( *zDelta!='\n' ){
+  if( lenDelta<=0 || *zDelta!='\n' ){
    /* ERROR: size integer not terminated by "\n" */
    return -1;
  }
@@ -609,11 +619,12 @@ static int rbuDeltaApply(
  while( *zDelta && lenDelta>0 ){
    unsigned int cnt, ofst;
    cnt = rbuDeltaGetInt(&zDelta, &lenDelta);
+    if( lenDelta<=0 ) return -1;
    switch( zDelta[0] ){
      case '@': {
        zDelta++; lenDelta--;
        ofst = rbuDeltaGetInt(&zDelta, &lenDelta);
-        if( lenDelta>0 && zDelta[0]!=',' ){
+        if( lenDelta>0 || zDelta[0]!=',' ){
          /* ERROR: copy command not terminated by ',' */
          return -1;
        }
@@ -638,7 +649,7 @@ static int rbuDeltaApply(
          /* ERROR:  insert command gives an output larger than predicted */
          return -1;
        }
-        if( (int)cnt>lenDelta ){
+        if( (i64)cnt>(i64)lenDelta ){
          /* ERROR: insert count exceeds size of delta */
          return -1;
        }
@@ -676,7 +687,7 @@ static int rbuDeltaApply(
 static int rbuDeltaOutputSize(const char *zDelta, int lenDelta){
  int size;
  size = rbuDeltaGetInt(&zDelta, &lenDelta);
-  if( *zDelta!='\n' ){
+  if( lenDelta<=0 || *zDelta!='\n' ){
    /* ERROR: size integer not terminated by "\n" */
    return -1;
  }
--- a/18
+++ b/18
@@ -1,5 +1,5 @@
-C Avoid\sa\spossible\sinteger\soverflow\swhen\sfts5\stokenizes\sa\svery\slarge\sdocument.\sOnly\spossible\swith\snon-standard\sbuilds\sthat\suse\slarge\svalues\sof\sSQLITE_MAX_LENGTH.\sBug\s[bugs:/info/2026-06-09T05:27:16Z\s|\s2026-06-09T05:27:16Z].
-D 2026-06-09T10:43:37.008
+C Harden\scode\sthat\sprocesses\sFossil\sDeltas\sagainst\sOOM\sand\smaliciously\nmalformed\sdelta\sblobs.\n[bugs:/info/2026-06-10T07:01:00Z|Bug\s2026-06-10T07:01:00Z]\sand\n[bugs:/info/2026-06-10T07:06:43Z|Bug\s2026-06-10T07:06:43Z].
+D 2026-06-10T09:51:33.214
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -379,7 +379,7 @@ F ext/misc/diskused.c 8acb4f27488fd8b9bdb0a3d300a7bd761b797b6e7858ac8038398263ce
 F ext/misc/eval.c 04bc9aada78c888394204b4ed996ab834b99726fb59603b0ee3ed6e049755dc1
 F ext/misc/explain.c 9670c8ff7b255eea7845abc5123a4958e74016c16990b10497e56380f91704b9
 F ext/misc/fileio.c 936c0a7b3382a047d833ad33f62ba59a3847b79ea745bf529797cd344966fbb0
-F ext/misc/fossildelta.c 6aa3f15279cd2d796583e3ff654be7d2df745fdbea7987c1640e78ce1fac899e
+F ext/misc/fossildelta.c 37b67b2710a0dd2da7b3aeea19388a069471eb0fc04702a0521237770d0d04f1
 F ext/misc/fuzzer.c decaca5a3479dfba69576cd41d4e17161eaf154a5438e12d316bbc5853571802
 F ext/misc/ieee754.c 2901d08a586d00a1d3c0fd89e03c57ee9e2b5f013b0daab9e49c7a48a9d5946b
 F ext/misc/memstat.c 03ab52d2d841eb3f55118105c1964d5225f152b23bd708844c648b48d14ccbcf
@@ -470,7 +470,7 @@ F ext/rbu/rbuvacuum.test e3585cfda220038e8186c583e9bd2aaa9eccd0a5c2e40ed861de3c9
 F ext/rbu/rbuvacuum2.test 1a9bd41f127be2826de2a65204df9118525a8af8d16e61e6bc63ba3ac0010a23
 F ext/rbu/rbuvacuum3.test 3ce42695fdf21aaa3499e857d7d4253bc499ad759bcd6c9362042c13cd37d8de
 F ext/rbu/rbuvacuum4.test ffccd22f67e2d0b380d2889685742159dfe0d19a3880ca3d2d1d69eefaebb205
-F ext/rbu/sqlite3rbu.c 28246b647831409e84dfb8286fbeda55f1de89e934571509a23a67ada572d0c0
+F ext/rbu/sqlite3rbu.c b1a961fb22f58355187947efed9d2a43396f015d6db2924ec4596259badcaddf
 F ext/rbu/sqlite3rbu.h e3a5bf21e09ca93ce4e8740e00d6a853e90a697968ec0ea98f40826938bdb68e
 F ext/rbu/test_rbu.c 8b6e64e486c28c41ef29f6f4ea6be7b3091958987812784904f5e903f6b56418
 F ext/recover/dbdata.c 10d3c56968a9af6853722a47280805ad1564714d79ea45ac6f7da14bb57fd137
@@ -2188,7 +2188,7 @@ F tool/soak1.tcl a3892082ed1079671565c044e93b55c3c7f38829aedf53cc597c65d23ffdadd
 F tool/spaceanal.tcl 1f83962090a6b60e1d7bf92495d643e622bef9fe82ea3f2d22350dcbce9a12d0
 F tool/spellsift.tcl 52b4b04dc4333c7ab024f09d9d66ed6b6f7c6eb00b38497a09f338fa55d40618 x
 F tool/split-sqlite3c.tcl 4969fd642dad0ea483e4e104163021d92baf98f6a8eac981fe48525f9b873430
-F tool/sqldiff.c de59a4eecbc802db8ad053889c10e6f8b8427b6f349199ee79938c92c20860dd
+F tool/sqldiff.c e581749af18f02a72cd18f56b465df1bef630544aebdf13993e2be55e4158f94
 F tool/sqlite3_analyzer.c.in 14f02cb5ec3c264cd6107d1f1dad77092b1cf440fc196c30b69ae87b56a1a43b
 F tool/sqlite3_rsync.c d9ce999e5b3aa9f36de44b321755622e52258774889bd804ba56f00eca01af50
 F tool/sqltclsh.c.in c103c6fc7d42bce611f9d4596774d60b7ef3d0b291a1f58c9e6184e458b89296
@@ -2209,8 +2209,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 77f615d9833b1f5eaabcb1a6b59af3a6698752abcd16592091f1630beec5969e
-R 16273cfea2a855d2524f9d540b776984
-U dan
-Z fcb16bea414d9bbab848fe9569966094
+P d562e91374e2bebcf75a00776b4def532bb71914a07e37c8507f7a5918db1d3b
+R 464cd416239cf2d114135a13f824196d
+U drh
+Z 8799fd27385d3bd24838dc796c1988a4
 # Remove this line to create a well-formed Fossil manifest.
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d562e91374e2bebcf75a00776b4def532bb71914a07e37c8507f7a5918db1d3b
+67271c31292bc1bddbb5e144c881c85c9f91b3963a1db4bae1f738adab50f7c0
--- a/tool/sqldiff.c
+++ b/tool/sqldiff.c
@@ -894,7 +894,8 @@ static unsigned int checksum(const char *zIn, size_t N){
 ** The delta string will be NUL-terminated, but it might also contain
 ** embedded NUL characters if either the zSrc or zOut files are
 ** binary.  This function returns the length of the delta string
-** in bytes, excluding the final NUL terminator character.
+** in bytes, excluding the final NUL terminator character.  Return 0
+** if an OOM occurs.
 **
 ** Output Format:
 **
@@ -986,6 +987,7 @@ static int rbuDeltaCreate(
  */
  nHash = lenSrc/NHASH;
  collide = sqlite3_malloc64( nHash*2*sizeof(int) );
+  if( collide==0 ) return 0;
  landmark = &collide[nHash];
  memset(landmark, -1, nHash*sizeof(int));
  memset(collide, -1, nHash*sizeof(int));
@@ -1309,7 +1311,7 @@ static void rbudiff_one_table(const char *zTab, FILE *out){

          aDelta = sqlite3_malloc64(nFinal + 60);
          nDelta = rbuDeltaCreate(aSrc, nSrc, aFinal, nFinal, aDelta);
-          if( nDelta<nFinal ){
+          if( nDelta>0 && nDelta<nFinal ){
            int j;
            sqlite3_fprintf(out, "x'");
            for(j=0; j<nDelta; j++) sqlite3_fprintf(out, "%02x", (u8)aDelta[j]);