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Code Issues Projects Releases Packages Wiki Activity Actions 17

gh-88116: Avoid undefined behavior when decoding varints in code objects (#94375)

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Pablo Galindo Salgado 2022-06-28 14:24:54 +01:00 • committed by GitHub
parent 44fa03d748
commit c485ec014c
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2 changed files with 10 additions and 8 deletions
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2
Misc/NEWS.d/next/Core and Builtins/2022-06-28-12-41-17.gh-issue-88116.A7fEl_.rst Normal file
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@ -0,0 +1,2 @@
Fix an issue when reading line numbers from code objects if the encoded line
numbers are close to ``INT_MIN``. Patch by Pablo Galindo

16
Objects/codeobject.c
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@ -354,9 +354,9 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
static int static int
scan_varint(const uint8_t *ptr) scan_varint(const uint8_t *ptr)
{ {
int read = *ptr++; unsigned int read = *ptr++;
int val = read & 63; unsigned int val = read & 63;
int shift = 0; unsigned int shift = 0;
while (read & 64) { while (read & 64) {
read = *ptr++; read = *ptr++;
shift += 6; shift += 6;
@ -368,7 +368,7 @@ scan_varint(const uint8_t *ptr)
static int static int
scan_signed_varint(const uint8_t *ptr) scan_signed_varint(const uint8_t *ptr)
{ {
int uval = scan_varint(ptr); unsigned int uval = scan_varint(ptr);
if (uval & 1) { if (uval & 1) {
return -(int)(uval >> 1); return -(int)(uval >> 1);
} }
@ -847,9 +847,9 @@ read_byte(PyCodeAddressRange *bounds)
static int static int
read_varint(PyCodeAddressRange *bounds) read_varint(PyCodeAddressRange *bounds)
{ {
int read = read_byte(bounds); unsigned int read = read_byte(bounds);
int val = read & 63; unsigned int val = read & 63;
int shift = 0; unsigned int shift = 0;
while (read & 64) { while (read & 64) {
read = read_byte(bounds); read = read_byte(bounds);
shift += 6; shift += 6;
@ -861,7 +861,7 @@ read_varint(PyCodeAddressRange *bounds)
static int static int
read_signed_varint(PyCodeAddressRange *bounds) read_signed_varint(PyCodeAddressRange *bounds)
{ {
int uval = read_varint(bounds); unsigned int uval = read_varint(bounds);
if (uval & 1) { if (uval & 1) {
return -(int)(uval >> 1); return -(int)(uval >> 1);
} }