kernel/linux.git/fs/squashfs/cache.c, branch v7.0-rc7

Squashfs: check metadata block offset is within range

2026-02-24T19:13:27+00:00

Syzkaller reports a "general protection fault in squashfs_copy_data" This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset. This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access. The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases. Link: https://lkml.kernel.org/r/20260217050955.138351-1-phillip@squashfs.org.uk Fixes: f400e12656ab ("Squashfs: cache operations") Reported-by: syzbot+a9747fe1c35a5b115d3f@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/699234e2.a70a0220.2c38d7.00e2.GAE@google.com/ Signed-off-by: Phillip Lougher Cc: Christian Brauner Cc: Signed-off-by: Andrew Morton

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

squashfs: fix invalid pointer dereference in squashfs_cache_delete

2025-03-17T00:40:24+00:00

When mounting a squashfs fails, squashfs_cache_init() may return an error pointer (e.g., -ENOMEM) instead of NULL. However, squashfs_cache_delete() only checks for a NULL cache, and attempts to dereference the invalid pointer. This leads to a kernel crash (BUG: unable to handle kernel paging request in squashfs_cache_delete). This patch fixes the issue by checking IS_ERR(cache) before accessing it. Link: https://lkml.kernel.org/r/20250306132855.2030-1-zhiyuzhang999@gmail.com Fixes: 49ff29240ebb ("squashfs: make squashfs_cache_init() return ERR_PTR(-ENOMEM)") Signed-off-by: Zhiyu Zhang Reported-by: Zhiyu Zhang Closes: https://lore.kernel.org/linux-fsdevel/CALf2hKvaq8B4u5yfrE+BYt7aNguao99mfWxHngA+=o5hwzjdOg@mail.gmail.com/ Tested-by: Zhiyu Zhang Reviewed-by: Phillip Lougher Signed-off-by: Andrew Morton

squashfs: make squashfs_cache_init() return ERR_PTR(-ENOMEM)

2025-01-25T06:45:34+00:00

Patch series "squashfs: reduce memory usage and update docs". This patchset reduces the amount of memory that Squashfs uses when CONFIG_FILE_DIRECT is configured, and updates various out of date information in the documentation and Kconfig. This patch (of 4): Make squashfs_cache_init() return an ERR_PTR(-ENOMEM) on failure rather than NULL. This tidies up some calling code, but, it also allows NULL to be returned as a valid result when a cache hasn't be allocated. Link: https://lkml.kernel.org/r/20241229233752.54481-1-phillip@squashfs.org.uk Link: https://lkml.kernel.org/r/20241229233752.54481-2-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher Signed-off-by: Andrew Morton

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 35

2019-05-24T15:27:11+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 23 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.458548087@linutronix.de Signed-off-by: Greg Kroah-Hartman

squashfs: be more careful about metadata corruption

2018-07-29T19:44:46+00:00

Anatoly Trosinenko reports that a corrupted squashfs image can cause a kernel oops. It turns out that squashfs can end up being confused about negative fragment lengths. The regular squashfs_read_data() does check for negative lengths, but squashfs_read_metadata() did not, and the fragment size code just blindly trusted the on-disk value. Fix both the fragment parsing and the metadata reading code. Reported-by: Anatoly Trosinenko Cc: Al Viro Cc: Phillip Lougher Cc: stable@kernel.org Signed-off-by: Linus Torvalds

mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage

2016-04-04T17:41:08+00:00

Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08+00:00

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

Squashfs: Generalise paging handling in the decompressors

2013-11-20T03:59:01+00:00

Further generalise the decompressors by adding a page handler abstraction. This adds helpers to allow the decompressors to access and process the output buffers in an implementation independant manner. This allows different types of output buffer to be passed to the decompressors, with the implementation specific aspects handled at decompression time, but without the knowledge being held in the decompressor wrapper code. This will allow the decompressors to handle Squashfs cache buffers, and page cache pages. This patch adds the abstraction and an implementation for the caches. Signed-off-by: Phillip Lougher Reviewed-by: Minchan Kim