diff options
author | NARUSE, Yui <naruse@airemix.jp> | 2023-03-17 13:40:04 +0900 |
---|---|---|
committer | NARUSE, Yui <naruse@airemix.jp> | 2023-03-17 13:40:04 +0900 |
commit | f3abe5ba645839fb2a686aee18d3466b59256af0 (patch) | |
tree | f5b5da96aa8e41115915eea4309707dcd100f88b /variable.c | |
parent | b309c246ee70926d593d3857e1625202e2d0f67b (diff) |
merge revision(s) 0700d0fd1c77b4fddf803dea3c10be654df600ff,62c2082f1f726cb90d8c332fbedbecf41d5d82ec: [Backport #19469]
Fix indentation in vm_setivar_default
---
vm_insnhelper.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
[Bug #19469] Fix crash when resizing generic iv list
The following script can sometimes trigger a crash:
```ruby
GC.stress = true
class Array
def foo(bool)
if bool
@a = 1
@b = 2
@c = 1
else
@c = 1
end
end
end
obj = []
obj.foo(true)
obj2 = []
obj2.foo(false)
obj3 = []
obj3.foo(true)
```
This is because vm_setivar_default calls rb_ensure_generic_iv_list_size
to resize the iv list. However, the call to gen_ivtbl_resize reallocs
the iv list, and then inserts into the generic iv table. If the
st_insert triggers a GC then the old iv list will be read during
marking, causing a use-after-free bug.
Co-Authored-By: Jemma Issroff <jemmaissroff@gmail.com>
---
internal/variable.h | 2 +-
variable.c | 23 ++++++++++++++++++-----
vm_insnhelper.c | 4 ++--
3 files changed, 21 insertions(+), 8 deletions(-)
Diffstat (limited to 'variable.c')
-rw-r--r-- | variable.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/variable.c b/variable.c index 0fd4a80887..c409209117 100644 --- a/variable.c +++ b/variable.c @@ -66,7 +66,10 @@ static st_table *generic_iv_tbl_; struct ivar_update { struct gen_ivtbl *ivtbl; uint32_t iv_index; - rb_shape_t* shape; + uint32_t max_index; +#if !SHAPE_IN_BASIC_FLAGS + rb_shape_t *shape; +#endif }; void @@ -1018,7 +1021,7 @@ generic_ivar_update(st_data_t *k, st_data_t *v, st_data_t u, int existing) } } FL_SET((VALUE)*k, FL_EXIVAR); - ivtbl = gen_ivtbl_resize(ivtbl, ivup->shape->next_iv_index); + ivtbl = gen_ivtbl_resize(ivtbl, ivup->max_index); // Reinsert in to the hash table because ivtbl might be a newly resized chunk of memory *v = (st_data_t)ivtbl; ivup->ivtbl = ivtbl; @@ -1281,7 +1284,10 @@ generic_ivar_set(VALUE obj, ID id, VALUE val) RUBY_ASSERT(index == (shape->next_iv_index - 1)); } + ivup.max_index = shape->next_iv_index; +#if !SHAPE_IN_BASIC_FLAGS ivup.shape = shape; +#endif RB_VM_LOCK_ENTER(); { @@ -1382,15 +1388,22 @@ rb_ensure_iv_list_size(VALUE obj, uint32_t current_capacity, uint32_t new_capaci } struct gen_ivtbl * -rb_ensure_generic_iv_list_size(VALUE obj, uint32_t newsize) +rb_ensure_generic_iv_list_size(VALUE obj, rb_shape_t *shape, uint32_t newsize) { struct gen_ivtbl * ivtbl = 0; RB_VM_LOCK_ENTER(); { if (UNLIKELY(!gen_ivtbl_get_unlocked(obj, 0, &ivtbl) || newsize > ivtbl->numiv)) { - ivtbl = gen_ivtbl_resize(ivtbl, newsize); - st_insert(generic_ivtbl_no_ractor_check(obj), (st_data_t)obj, (st_data_t)ivtbl); + struct ivar_update ivup = { + .iv_index = newsize - 1, + .max_index = newsize, +#if !SHAPE_IN_BASIC_FLAGS + .shape = shape +#endif + }; + st_update(generic_ivtbl_no_ractor_check(obj), (st_data_t)obj, generic_ivar_update, (st_data_t)&ivup); + ivtbl = ivup.ivtbl; FL_SET_RAW(obj, FL_EXIVAR); } } |