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| author |   Josef Bacik <josef@toxicpanda.com> | 2021-02-25 17:20:49 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-26 09:41:03 -0800 |
| commit | 4508943794efdd94171549c0bd52810e2f4ad9fe (patch) | |
| tree | 6b6930dc88e157d4210ac4b2396816420f800ed1 /fs/proc | |
| parent | proc/wchan: use printk format instead of lookup_symbol_name() (diff) | |
| download | linux-dev-4508943794efdd94171549c0bd52810e2f4ad9fe.tar.xz linux-dev-4508943794efdd94171549c0bd52810e2f4ad9fe.zip | |
proc: use kvzalloc for our kernel buffer
Since
sysctl: pass kernel pointers to ->proc_handler
we have been pre-allocating a buffer to copy the data from the proc
handlers into, and then copying that to userspace. The problem is this
just blindly kzalloc()'s the buffer size passed in from the read, which in
the case of our 'cat' binary was 64kib. Order-4 allocations are not
awesome, and since we can potentially allocate up to our maximum order, so
use kvzalloc for these buffers.
[willy@infradead.org: changelog tweaks]
Link: https://lkml.kernel.org/r/6345270a2c1160b89dd5e6715461f388176899d1.1612972413.git.josef@toxicpanda.com
Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
CC: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/proc_sysctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 656ba24c317d..984e42f8cb11 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -571,7 +571,7 @@ static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, error = -ENOMEM; if (count >= KMALLOC_MAX_SIZE) goto out; - kbuf = kzalloc(count + 1, GFP_KERNEL); + kbuf = kvzalloc(count + 1, GFP_KERNEL); if (!kbuf) goto out; @@ -600,7 +600,7 @@ static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, error = count; out_free_buf: - kfree(kbuf); + kvfree(kbuf); out: sysctl_head_finish(head); |