summaryrefslogtreecommitdiff
path: root/fs/proc
diff options
context:
space:
mode:
authorJosef Bacik <josef@toxicpanda.com>2021-02-25 17:20:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:03 -0800
commit4508943794efdd94171549c0bd52810e2f4ad9fe (patch)
tree6b6930dc88e157d4210ac4b2396816420f800ed1 /fs/proc
parent152c432b128cb043fc107e8f211195fe94b2159c (diff)
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.c4
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);