From: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
To: linux-fsdevel@vger.kernel.org
Cc: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>,
David Disseldorp <ddiss@suse.de>,
Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Michel Lespinasse <walken@google.com>,
Helge Deller <deller@gmx.de>, Oleg Nesterov <oleg@redhat.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH] proc: Avoid mixing integer types in mem_rw()
Date: Wed, 12 May 2021 09:52:12 -0300 [thread overview]
Message-ID: <20210512125215.3348316-1-marcelo.cerri@canonical.com> (raw)
Use size_t when capping the count argument received by mem_rw(). Since
count is size_t, using min_t(int, ...) can lead to a negative value
that will later be passed to access_remote_vm(), which can cause
unexpected behavior.
Since we are capping the value to at maximum PAGE_SIZE, the conversion
from size_t to int when passing it to access_remote_vm() as "len"
shouldn't be a problem.
Reviewed-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
---
fs/proc/base.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3851bfcdba56..8dbc6a1aaadb 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -854,7 +854,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
while (count > 0) {
- int this_len = min_t(int, count, PAGE_SIZE);
+ size_t this_len = min_t(size_t, count, PAGE_SIZE);
if (write && copy_from_user(page, buf, this_len)) {
copied = -EFAULT;
--
2.25.1
next reply other threads:[~2021-05-12 12:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 12:52 Marcelo Henrique Cerri [this message]
2021-05-12 13:19 ` [PATCH] proc: Avoid mixing integer types in mem_rw() Alexey Dobriyan
2021-05-12 13:40 ` Marcelo Henrique Cerri
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