From: Marcelo Henrique Cerri <marcelo.cerri@xxxxxxxxxxxxx> [ Upstream commit d238692b4b9f2c36e35af4c6e6f6da36184aeb3e ] 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@xxxxxxxxxxxxx Reviewed-by: David Disseldorp <ddiss@xxxxxxx> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@xxxxxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Souza Cascardo <cascardo@xxxxxxxxxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 df9b17dd92cb..5d52aea8d7e7 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -855,7 +855,7 @@ 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; -- 2.30.2
