linux.git/kernel/acct.c, branch v6.1.168

acct: block access to kernel internal filesystems

2025-03-07T15:56:39+00:00

commit 890ed45bde808c422c3c27d3285fc45affa0f930 upstream.

There's no point in allowing anything kernel internal nor procfs or
sysfs.

Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com
Link: https://lore.kernel.org/r/20250211-work-acct-v1-2-1c16aecab8b3@kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Amir Goldstein 
Reported-by: Zicheng Qu 
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner 
Signed-off-by: Greg Kroah-Hartman

acct: perform last write from workqueue

2025-03-07T15:56:39+00:00

commit 56d5f3eba3f5de0efdd556de4ef381e109b973a9 upstream.

In [1] it was reported that the acct(2) system call can be used to
trigger NULL deref in cases where it is set to write to a file that
triggers an internal lookup. This can e.g., happen when pointing acc(2)
to /sys/power/resume. At the point the where the write to this file
happens the calling task has already exited and called exit_fs(). A
lookup will thus trigger a NULL-deref when accessing current->fs.

Reorganize the code so that the the final write happens from the
workqueue but with the caller's credentials. This preserves the
(strange) permission model and has almost no regression risk.

This api should stop to exist though.

Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com [1]
Link: https://lore.kernel.org/r/20250211-work-acct-v1-1-1c16aecab8b3@kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Zicheng Qu 
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner 
Signed-off-by: Greg Kroah-Hartman

acct: fix potential integer overflow in encode_comp_t()

2022-12-31T12:32:58+00:00

[ Upstream commit c5f31c655bcc01b6da53b836ac951c1556245305 ]

The integer overflow is descripted with following codes:
  > 317 static comp_t encode_comp_t(u64 value)
  > 318 {
  > 319         int exp, rnd;
    ......
  > 341         exp <<= MANTSIZE;
  > 342         exp += value;
  > 343         return exp;
  > 344 }

Currently comp_t is defined as type of '__u16', but the variable 'exp' is
type of 'int', so overflow would happen when variable 'exp' in line 343 is
greater than 65535.

Link: https://lkml.kernel.org/r/20210515140631.369106-3-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian 
Cc: Hanjun Guo 
Cc: Randy Dunlap 
Cc: Vlastimil Babka 
Cc: Zhang Jinhao 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

acct: use VMA iterator instead of linked list

2022-09-27T02:46:22+00:00

The VMA iterator is faster than the linked list.

Link: https://lkml.kernel.org/r/20220906194824.2110408-47-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Liam R. Howlett 
Acked-by: Vlastimil Babka 
Reviewed-by: Davidlohr Bueso 
Tested-by: Yu Zhao 
Cc: Catalin Marinas 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: SeongJae Park 
Cc: Sven Schnelle 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

kernel/acct: move acct sysctls to its own file

2022-04-06T20:43:44+00:00

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

All filesystem syctls now get reviewed by fs folks. This commit
follows the commit of fs, move the acct sysctl to its own file,
kernel/acct.c.

Signed-off-by: tangmeng 
Signed-off-by: Luis Chamberlain

kernel: remove spurious blkdev.h includes

2021-10-18T12:17:01+00:00

Various files have acquired spurious includes of  over
time.  Remove them.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20210920123328.1399408-7-hch@lst.de
Signed-off-by: Jens Axboe

kernel/acct.c: use dedicated helper to access rlimit values

2021-09-08T18:50:26+00:00

Use rlimit() helper instead of manually writing whole chain from
task to rlimit value. See patch "posix-cpu-timers: Use dedicated
helper to access rlimit values".

Link: https://lkml.kernel.org/r/20210728030822.524789-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang 
Reported-by: Zeal Robot 
Cc: Randy Dunlap 
Cc: sh_def@163.com 
Cc: Yang Yang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel/acct.c: use #elif instead of #end and #elif

2020-12-16T06:46:15+00:00

Cleanup: use #elif instead of #end and #elif.

Link: https://lkml.kernel.org/r/20201015150736.GA91603@rlk
Signed-off-by: Hui Su 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: acct.c: fix some kernel-doc nits

2020-10-16T18:11:19+00:00

Fix kernel-doc notation to use the documented Returns: syntax and place
the function description for acct_process() on the first line where it
should be.

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Cc: Alexander Viro 
Link: https://lkml.kernel.org/r/b4c33e5d-98e8-0c47-77b6-ac1859f94d7f@infradead.org
Signed-off-by: Linus Torvalds

kernel/: fix repeated words in comments

2020-10-16T18:11:19+00:00

Fix multiple occurrences of duplicated words in kernel/.

Fix one typo/spello on the same line as a duplicate word.  Change one
instance of "the the" to "that the".  Otherwise just drop one of the
repeated words.

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org
Signed-off-by: Linus Torvalds