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Fix spurious * overflow check in calloc implementation #1932

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Fix spurious * overflow check in calloc implementation #1932

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c8151c3
Add test for overflows due to mult in calloc implementation
karoliineh Jan 28, 2026
4be6a4f
Fix spurious * overflow check in calloc implementation
karoliineh Jan 28, 2026
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5 changes: 4 additions & 1 deletion src/analyses/base.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -2763,7 +2763,10 @@ struct
let blob_set = Option.map_default (fun heap_var -> [heap_var, TVoid [], VD.Blob (VD.bot (), sizeval, ZeroInit.calloc)]) [] heap_var in
set_many ~man st ((eval_lv ~man st lv, (Cilfacade.typeOfLval lv), Address addr):: blob_set)
else
let blobsize = ID.mul (ID.cast_to ~kind:Internal ik @@ sizeval) (ID.cast_to ~kind:Internal ik @@ countval) in (* TODO: proper castkind *)
let blobsize = (* only speculative during ID.mul *)
let@ () = GobRef.wrap AnalysisState.executing_speculative_computations true in
ID.mul (ID.cast_to ~kind:Internal ik @@ sizeval) (ID.cast_to ~kind:Internal ik @@ countval) (* TODO: proper castkind *)
in
let offset = `Index (IdxDom.of_int (Cilfacade.ptrdiff_ikind ()) Z.zero, `NoOffset) in
(* the heap_var is the base address of the allocated memory, but we need to keep track of the offset for the blob *)
let addr_offset = AD.map (fun a -> Addr.add_offset a offset) addr in
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8 changes: 8 additions & 0 deletions tests/regression/39-signed-overflows/17-calloc-mult-speculating.c
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@@ -0,0 +1,8 @@
// PARAM: --enable ana.int.interval
#include <stdlib.h>

int main() {
size_t a, b;
unsigned char *randomString = (unsigned char *)calloc(a,b); // NOWARN (signed integer overflow in *)
return 0;
}
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