Prevent overly long JSON paths from using too much stack space.

FossilOrigin-Name: 82a0794814bbc095235f8158a4129a5d83f6af1b0c27cb56449ea32feb44faf5

manifest

@@ -1,5 +1,5 @@
-C Limit\sJSONB\srecursion\sdepth\sin\sthe\sjson_patch()\sfunction.
-D 2026-03-24T12:39:05.703
+C Prevent\soverly\slong\sJSON\spaths\sfrom\susing\stoo\smuch\sstack\sspace.
+D 2026-03-24T19:26:05.509
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -694,7 +694,7 @@ F src/hash.h 46b92795a95bfefb210f52f0c316e9d7cdbcdd7e7fcfb0d8be796d3a5767cddf
 F src/hwtime.h 21c2cf1f736e7b97502c3674d0c386db3f06870d6f10d0cf8174e2a4b8cb726e
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c dfd311b0ac2d4f6359e62013db67799757f4d2cc56cca5c10f4888acfbbfa3fd
-F src/json.c 3d790a2822cf3938d808dd4c82713e640f2fc410504b0f853dc32b8fa585bad4
+F src/json.c 5027b856cd9b621dc9ba66b211e21a440ccdc63cefdefb44c51e7d3ac550d1a4
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 187929338d21f43cbdea359a3c1ec61294f39b7f9032e824c1dbb79f9994c838
 F src/main.c 31a13302193fbd51279c7e69cdfa0320d0de7629f9151e0964c1d320e8bdd7a4
@@ -2195,8 +2195,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 82036fafa175e798fd32b3dc4ad043fc2bbe2bb2af17781f12dcb4d23a233865
-R cfe70b6eb98b5198569bd46361e5c403
+P f8659b700c0088abe19ce65fec032c1005a1f750566488f4578256d41558770c
+R 758e0af8a0882e7e9923c695c5403a23
 U drh
-Z 24e4693854a4d68b165699d3ce0f66fc
+Z 1af8ca46b9aa6ac26d04c5ed95b2b6cf
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-f8659b700c0088abe19ce65fec032c1005a1f750566488f4578256d41558770c
+82a0794814bbc095235f8158a4129a5d83f6af1b0c27cb56449ea32feb44faf5

src/json.c

@@ -2898,7 +2898,8 @@ static int jsonLabelCompare(
 #define JSON_LOOKUP_ERROR      0xffffffff
 #define JSON_LOOKUP_NOTFOUND   0xfffffffe
 #define JSON_LOOKUP_NOTARRAY   0xfffffffd
-#define JSON_LOOKUP_PATHERROR  0xfffffffc
+#define JSON_LOOKUP_TOODEEP    0xfffffffc
+#define JSON_LOOKUP_PATHERROR  0xfffffffb
 #define JSON_LOOKUP_ISERROR(x) ((x)>=JSON_LOOKUP_PATHERROR)
 
 /* Forward declaration */
@@ -2945,7 +2946,12 @@ static u32 jsonCreateEditSubstructure(
     pIns->eEdit = pParse->eEdit;
     pIns->nIns = pParse->nIns;
     pIns->aIns = pParse->aIns;
+    pIns->iDepth = pParse->iDepth+1;
+    if( pIns->iDepth >= JSON_MAX_DEPTH ){
+      return JSON_LOOKUP_TOODEEP;
+    }
     rc = jsonLookupStep(pIns, 0, zTail, 0);
+    pParse->iDepth--;
     pParse->oom |= pIns->oom;
   }
   return rc;  /* Error code only */
@@ -3051,7 +3057,11 @@ static u32 jsonLookupStep(
         n = jsonbPayloadSize(pParse, v, &sz);
         if( n==0 || v+n+sz>iEnd ) return JSON_LOOKUP_ERROR;
         assert( j>0 );
+        if( ++pParse->iDepth >= JSON_MAX_DEPTH ){
+          return JSON_LOOKUP_TOODEEP;
+        }
         rc = jsonLookupStep(pParse, v, &zPath[i], j);
+        pParse->iDepth--;
         if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
         return rc;
       }
@@ -3137,7 +3147,11 @@ static u32 jsonLookupStep(
     iEnd = j+sz;
     while( j<iEnd ){
       if( kk==0 ){
+        if( ++pParse->iDepth >= JSON_MAX_DEPTH ){
+          return JSON_LOOKUP_TOODEEP;
+        }
         rc = jsonLookupStep(pParse, j, &zPath[i+1], 0);
+        pParse->iDepth--;
         if( pParse->delta ) jsonAfterEditSizeAdjust(pParse, iRoot);
         return rc;
       }
@@ -3473,9 +3487,10 @@ static int jsonFunctionArgToBlob(
 **
 ** The specifics of the error are determined by the rc argument.
 **
-**          rc                   error
-**  -----------------       ----------------
+**          rc                        error
+**  -----------------       ----------------------
 **  JSON_LOOKUP_ARRAY       "not an array"
+**  JSON_LOOKUP_TOODEEP     "JSON nested too deep"
 **  JSON_LOOKUP_ERROR       "malformed JSON"
 **  otherwise...            "bad JSON path"
 **
@@ -3492,6 +3507,8 @@ static char *jsonBadPathError(
     zMsg = sqlite3_mprintf("not an array element: %Q", zPath);
   }else if( rc==(int)JSON_LOOKUP_ERROR ){
     zMsg = sqlite3_mprintf("malformed JSON");
+  }else if( rc==(int)JSON_LOOKUP_TOODEEP ){
+    zMsg = sqlite3_mprintf("JSON path too deep");
   }else{
     zMsg = sqlite3_mprintf("bad JSON path: %Q", zPath);
   }
@@ -3554,6 +3571,7 @@ static void jsonInsertIntoBlob(
       p->nIns = ax.nBlob;
       p->aIns = ax.aBlob;
       p->delta = 0;
+      p->iDepth = 0;
       rc = jsonLookupStep(p, 0, zPath+1, 0);
     }
     jsonParseReset(&ax);