From d238692b4b9f2c36e35af4c6e6f6da36184aeb3e Mon Sep 17 00:00:00 2001 From: Marcelo Henrique Cerri Date: Wed, 30 Jun 2021 18:54:38 -0700 Subject: proc: Avoid mixing integer types in mem_rw() 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. Link: https://lkml.kernel.org/r/20210512125215.3348316-1-marcelo.cerri@canonical.com Reviewed-by: David Disseldorp Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Marcelo Henrique Cerri Cc: Alexey Dobriyan Cc: Souza Cascardo Cc: Christian Brauner Cc: Michel Lespinasse Cc: Helge Deller Cc: Oleg Nesterov Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/proc') diff --git a/fs/proc/base.c b/fs/proc/base.c index 9cbd915025ad..a0a2fc1c9da2 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; -- cgit v1.2.3