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Fixes to the substr() SQL function so that it can handle ridiculously large

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numbers in its 2nd and 3rd arguments without signed integer overflows.

FossilOrigin-Name: c1de8f916ea617109a903c436c57d082756fbb2b933ba9ce6998b9b912b12dea
This commit is contained in:
drh
2024-12-28 12:32:01 +00:00
parent 9591d3fe93
commit e0190a6984
3 changed files with 18 additions and 19 deletions
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23
src/func.c
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@@ -354,7 +354,6 @@ static void substrFunc(
int len;
int p0type;
i64 p1, p2;
int negP2 = 0;
assert( argc==3 || argc==2 );
if( sqlite3_value_type(argv[1])==SQLITE_NULL
@@ -389,18 +388,17 @@ static void substrFunc(
#endif
if( argc==3 ){
p2 = sqlite3_value_int64(argv[2]);
if( p2<0 ){
p2 = -p2;
negP2 = 1;
}
}else{
p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
}
if( p1<0 ){
p1 += len;
if( p1<0 ){
p2 += p1;
if( p2<0 ) p2 = 0;
if( p2<0 ){
p2 = 0;
}else{
p2 += p1;
}
p1 = 0;
}
}else if( p1>0 ){
@@ -408,12 +406,13 @@ static void substrFunc(
}else if( p2>0 ){
p2--;
}
if( negP2 ){
p1 -= p2;
if( p1<0 ){
p2 += p1;
p1 = 0;
if( p2<0 ){
if( p2<-p1 ){
p2 = p1;
}else{
p2 = -p2;
}
p1 -= p2;
}
assert( p1>=0 && p2>=0 );
if( p0type!=SQLITE_BLOB ){