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https://github.com/carlospolop/hacktricks
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189 lines
8.8 KiB
Markdown
189 lines
8.8 KiB
Markdown
# Heap Functions Security Checks
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Support HackTricks</summary>
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* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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## unlink
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For more info check:
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{% content-ref url="unlink.md" %}
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[unlink.md](unlink.md)
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{% endcontent-ref %}
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This is a summary of the performed checks:
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* Check if the indicated size of the chunk is the same as the `prev_size` indicated in the next chunk
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* Error message: `corrupted size vs. prev_size`
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* Check also that `P->fd->bk == P` and `P->bk->fw == P`
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* Error message: `corrupted double-linked list`
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* If the chunk is not small, check that `P->fd_nextsize->bk_nextsize == P` and `P->bk_nextsize->fd_nextsize == P`
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* Error message: `corrupted double-linked list (not small)`
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## \_int\_malloc
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For more info check:
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{% content-ref url="malloc-and-sysmalloc.md" %}
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[malloc-and-sysmalloc.md](malloc-and-sysmalloc.md)
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{% endcontent-ref %}
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* **Checks during fast bin search:**
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* If the chunk is misaligned:
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* Error message: `malloc(): unaligned fastbin chunk detected 2`
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* If the forward chunk is misaligned:
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* Error message: `malloc(): unaligned fastbin chunk detected`
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* If the returned chunk has a size that isn't correct because of it's index in the fast bin:
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* Error message: `malloc(): memory corruption (fast)`
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* If any chunk used to fill the tcache is misaligned:
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* Error message: `malloc(): unaligned fastbin chunk detected 3`
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* **Checks during small bin search:**
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* If `victim->bk->fd != victim`:
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* Error message: `malloc(): smallbin double linked list corrupted`
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* **Checks during consolidate** performed for each fast bin chunk: 
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* If the chunk is unaligned trigger:
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* Error message: `malloc_consolidate(): unaligned fastbin chunk detected`
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* If the chunk has a different size that the one it should because of the index it's in:
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* Error message: `malloc_consolidate(): invalid chunk size`
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* If the previous chunk is not in use and the previous chunk has a size different of the one indicated by prev\_chunk:
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* Error message: `corrupted size vs. prev_size in fastbins`
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* **Checks during unsorted bin search**:
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* If the chunk size is weird (too small or too big): 
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* Error message: `malloc(): invalid size (unsorted)`
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* If the next chunk size is weird (too small or too big):
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* Error message: `malloc(): invalid next size (unsorted)`
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* If the previous size indicated by the next chunk differs from the size of the chunk:
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* Error message: `malloc(): mismatching next->prev_size (unsorted)`
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* If not `victim->bck->fd == victim` or not `victim->fd == av (arena)`:
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* Error message: `malloc(): unsorted double linked list corrupted`
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* As we are always checking the las one, it's fd should be pointing always to the arena struct.
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* If the next chunk isn't indicating that the previous is in use:
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* Error message: `malloc(): invalid next->prev_inuse (unsorted)`
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* If `fwd->bk_nextsize->fd_nextsize != fwd`:
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* Error message: `malloc(): largebin double linked list corrupted (nextsize)`
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* If `fwd->bk->fd != fwd`:
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* Error message: `malloc(): largebin double linked list corrupted (bk)`
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* **Checks during large bin (by index) search:**
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* `bck->fd-> bk != bck`:
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* Error message: `malloc(): corrupted unsorted chunks`
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* **Checks during large bin (next bigger) search:**
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* `bck->fd-> bk != bck`:
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* Error message: `malloc(): corrupted unsorted chunks2`
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* **Checks during Top chunk use:**
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* `chunksize(av->top) > av->system_mem`:
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* Error message: `malloc(): corrupted top size`
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## `tcache_get_n`
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* **Checks in `tcache_get_n`:**
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* If chunk is misaligned:
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* Error message: `malloc(): unaligned tcache chunk detected`
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## `tcache_thread_shutdown`
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* **Checks in `tcache_thread_shutdown`:**
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* If chunk is misaligned:
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* Error message: `tcache_thread_shutdown(): unaligned tcache chunk detected`
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## `__libc_realloc`
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* **Checks in `__libc_realloc`:**
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* If old pointer is misaligned or the size was incorrect:
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* Error message: `realloc(): invalid pointer`
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## `_int_free`
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For more info check:
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{% content-ref url="free.md" %}
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[free.md](free.md)
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{% endcontent-ref %}
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* **Checks during the start of `_int_free`:**
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* Pointer is aligned:
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* Error message: `free(): invalid pointer`
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* Size larger than `MINSIZE` and size also aligned:
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* Error message: `free(): invalid size`
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* **Checks in `_int_free` tcache:**
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* If there are more entries than `mp_.tcache_count`:
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* Error message: `free(): too many chunks detected in tcache`
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* If the entry is not aligned:
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* Error message: `free(): unaligned chunk detected in tcache 2`
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* If the freed chunk was already freed and is present as chunk in the tcache:
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* Error message: `free(): double free detected in tcache 2`
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* **Checks in `_int_free` fast bin:**
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* If the size of the chunk is invalid (too big or small) trigger:
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* Error message: `free(): invalid next size (fast)`
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* If the added chunk was already the top of the fast bin:
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* Error message: `double free or corruption (fasttop)`
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* If the size of the chunk at the top has a different size of the chunk we are adding:
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* Error message: `invalid fastbin entry (free)`
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## **`_int_free_merge_chunk`**
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* **Checks in `_int_free_merge_chunk`:**
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* If the chunk is the top chunk:
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* Error message: `double free or corruption (top)`
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* If the next chunk is outside of the boundaries of the arena:
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* Error message: `double free or corruption (out)`
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* If the chunk is not marked as used (in the prev\_inuse from the following chunk):
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* Error message: `double free or corruption (!prev)`
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* If the next chunk has a too little size or too big:
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* Error message: `free(): invalid next size (normal)`
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* If the previous chunk is not in use, it will try to consolidate. But, if the `prev_size` differs from the size indicated in the previous chunk:
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* Error message: `corrupted size vs. prev_size while consolidating`
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## **`_int_free_create_chunk`**
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* **Checks in `_int_free_create_chunk`:**
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* Adding a chunk into the unsorted bin, check if `unsorted_chunks(av)->fd->bk == unsorted_chunks(av)`:
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* Error message: `free(): corrupted unsorted chunks`
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## `do_check_malloc_state`
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* **Checks in `do_check_malloc_state`:**
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* If misaligned fast bin chunk:
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* Error message: `do_check_malloc_state(): unaligned fastbin chunk detected`
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## `malloc_consolidate`
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* **Checks in `malloc_consolidate`:**
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* If misaligned fast bin chunk:
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* Error message: `malloc_consolidate(): unaligned fastbin chunk detected`
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* If incorrect fast bin chunk size:
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* Error message: `malloc_consolidate(): invalid chunk size`
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## `_int_realloc`
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* **Checks in `_int_realloc`:**
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* Size is too big or too small:
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* Error message: `realloc(): invalid old size`
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* Size of the next chunk is too big or too small:
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* Error message: `realloc(): invalid next size`
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{% hint style="success" %}
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Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Support HackTricks</summary>
|
|
|
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* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
|
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
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* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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{% endhint %}
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