From: Arnd Bergmann <arnd@xxxxxxxx>
The array_size() helper is used here to prevent accidental overflow in
mlx4_init_user_cqes(), but as this returns SIZE_MAX in case an overflow
would happen, the logic in copy_to_user() now detects that as overflowing
the source:
In file included from arch/x86/include/asm/preempt.h:9,
from include/linux/preempt.h:78,
from include/linux/percpu.h:6,
from include/linux/context_tracking_state.h:5,
from include/linux/hardirq.h:5,
from drivers/net/ethernet/mellanox/mlx4/cq.c:37:
In function 'check_copy_size',
inlined from 'copy_to_user' at include/linux/uaccess.h:190:6,
inlined from 'mlx4_init_user_cqes' at drivers/net/ethernet/mellanox/mlx4/cq.c:317:9,
inlined from 'mlx4_cq_alloc' at drivers/net/ethernet/mellanox/mlx4/cq.c:394:10:
include/linux/thread_info.h:244:4: error: call to '__bad_copy_from' declared with attribute error: copy source size is too small
244 | __bad_copy_from();
| ^~~~~~~~~~~~~~~~~
Move the size logic out, and instead use the same size value for the
comparison and the copy.
Fixes: f69bf5dee7ef ("net/mlx4: Use array_size() helper in copy_to_user()")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx4/cq.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c
index 4d4f9cf9facb..020cb8e2883f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cq.c
@@ -290,6 +290,7 @@ static void mlx4_cq_free_icm(struct mlx4_dev *dev, int cqn)
static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
{
int entries_per_copy = PAGE_SIZE / cqe_size;
+ size_t copy_size = array_size(entries, cqe_size);
void *init_ents;
int err = 0;
int i;
@@ -304,7 +305,7 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
*/
memset(init_ents, 0xcc, PAGE_SIZE);
- if (entries_per_copy < entries) {
+ if (copy_size > PAGE_SIZE) {
for (i = 0; i < entries / entries_per_copy; i++) {
err = copy_to_user((void __user *)buf, init_ents, PAGE_SIZE) ?
-EFAULT : 0;
@@ -315,7 +316,7 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size)
}
} else {
err = copy_to_user((void __user *)buf, init_ents,
- array_size(entries, cqe_size)) ?
+ copy_size) ?
-EFAULT : 0;
}
--
2.39.2
